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    Please note: I have copied this post across to the "in depth thread" should anyone wish to discuss any points that I have raised and share their views in a less frantic environment WINTER 2016/17 FULL REPORT No. 12 WITH FEBRUARY 5th INPUT This is by far my most upbeat report of the whole winter (whatever any of the 12z model output might say!) Brief Review Of The Last Week: The widely predicted change from the cold continental influence to the more unsettled Atlantic influence was completed early in the week but not without further cold days in the north and north-east at first. The named storms, indicated on much of the model output a week ago, did not reach us but took a more southerly track into France where they named one storm “Leiv” but fortunately the severest damage was restricted to a very small coastal region in western France. The following storms were less intense. We were on the northern edge with some rain and briefly some stronger winds in the south and south-west. Although temperatures have recovered to some extent they have (mostly) only slightly exceeded normal on a few days and were generally in single figures with even a little wintry precipitation on higher ground in some parts. The Current and Short Term Position: I felt that this milder spell would be brief and kept a careful watch on the European cold block which I have said time and again during the last month has been consistently under estimated by almost all the models. I believe that this is still being under estimated and this time it will greatly assist us in the feed of deeper cold air into the UK by next weekend. In fact, I felt so strongly about this that I started a “Daily European Temperature and Pressure Watch” three days ago. My latest update was posted this morning (see page 92). The cold block was only pushed slightly eastwards into western Asia. Much of central and eastern Europe only briefly saw temperatures rise slightly above freezing (for a couple of days). The UK Atlantic spell is being cut short. Fronts will be stalling across the country during the next three days as a Scandinavian HP takes hold. There may even be a little snow as the fronts return westwards before they fizzle out. Right now, pressure is building strongly from north-west Russia and is already ridging into Scandinavia – just look at my live pressure chart on page 92 and compare that to the 0650 chart. The deep cold is also steadily intensifying in north-west Russia and moving south-westwards into northern Scandinavia. The sub -20c pool of surface cold (some is nearer -30c) and sub -20c 850s are also expanding and moving steadily westwards and south-westwards. I believe that the transition may well be even faster than currently predicted with colder weather installed by mid-week. I also think that there is a good chance that the small area LP that moved across south-west England today will move away into France. Then the fronts associated with the following larger area of LP tomorrow may not make much progress into the UK and there might be a good chance of a new small LP forming on the warm front or near the occlusion which could move away south-eastwards and further undercut the block, introducing easterlies further south into the UK a day or so sooner. I demonstrated the predicted development of the Scandinavian HP in another post yesterday (see page 84) where I used all the Met Office fax charts. I had noted that their latest charts (which were issued several hours ahead of the 12z model output – they always give an advance clue to any likely near term changes) were showing the HP being maintained further north and west over Scandinavia and with a better alignment for the easterly on its southern flank. Some of the models are still struggling with the all important detail on this. I indicated this morning that there were already several undercutting LPs propping up the HP. Okay, I had better post the two live charts now to make my points clearer (but just take another look at all the charts on page 92 to fully appreciate the extent of today’s changes): EUROPEAN "LIVE" PRESSURE CHART EUROPEAN "LIVE" TEMPERATURE CHART At this stage, my take on this is that the Scandinavia HP will not sink southwards, at least for quite a few days. I also believe that with this and the under estimated depth and extent of the cold pools (upper and surface cold) that conditions will turn somewhat colder across the whole of the UK sooner than much of the recent model output has suggested. I do note that the 0z output has mostly upgraded the colder uppers. I am writing this part of my report at 1330 and by the time I post it this evening, the 12z output will have rolled out. I am expecting further upgrades over the next few runs but perhaps still with the odd single run/single model set back. The models mostly still need to factor in the current extent of the cold and as they update they should reflect these changes in the D3 to D6 range. Now, I am not trying to score points over anyone (and it would foolish to try to take on the models for any extended period) and I may be wrong about this but let’s look at some more evidence. I noted an interesting point that @johnholmes raised several days ago which I completely agree with. The strength and persistence of HP and/or cold blocks is frequently under estimated by the models. In fact I would say that this is often one of their most serious faults or shortcomings and presents huge timing issues and even leads to quite a different outcome on occasions. In the days when forecasters did not have access to computer models, satellite imagery and all the other modern tools, they often had difficulties in assessing the longevity of these blocks. Much of their forecast was based on pure experience and using analogue charts alongside the current data. As John says, it is amazing that these blocks still present such forecasting difficulties. Many on here have said, easterly airstreams have been much rarer in recent years. Back in the 1960s to 1980s they were so much more common. Not just in cold winters but we usually saw several of them even in predominantly mild winters. I can recall a great many examples of all sorts of types of easterlies but this is not the time or the appropriate thread to list them now. In broad terms, the most important component was “usually” the Scandinavian HP. Its position, orientation and how it developed was always so important. Some develop as a temporary extension of a Siberian HP. Some develop in situ, often after an Arctic incursion, when the LP fills up quickly and HP forms over the residual surface cold. Some are transient features and some stick around for days or even weeks on end. Some form when there is no cold pool to tap into. I recall a few easterlies with temps hardly below average. Some produce long periods of cold to very cold but completely dry weather. Some produce a few snow showers on exposed coasts but nothing more than a few flurries inland. A few produce much more convective conditions with rather heavier snow showers often merging into longer periods of snow. Isolated cold pools (those that have broken away from the main cold lobe, like the one indicated on one of the GEM runs two days ago (that disappeared on their next run), small disturbances and troughs can produce snowfall, sometimes developing quite unexpectedly. Streamers can form in the more favoured downwind well aligned spots (like the “Thames Streamer” on a direct easterly flow) and produce many hours of almost continuous snow showers with significant accumulations. There can sometime be more general snow events when Atlantic LPs and their attendant fronts come up against the cold block. Down here in the West Country there have been a number of severe blizzards when stalling fronts undercut the easterly or south-easterly flow. These are rare events but can turn up in mostly mild winters (such as February 1978) as well as in severe winters (with multiple events in 1947 and 1962-63). Sometimes an easterly is swept away rapidly by the Atlantic (probably with the Jet Stream powering up with a more direct attack). Sometimes a LP over Biscay or France veers the flow to the south and pulls in much milder air. So what sort of easterly will this one be and will it deliver any snow? Unfortunately, the answer is that I do not know for sure but there are some very positive signs. Factoring in some of what I’ve just mentioned, I am very encouraged in the way that this Scandinavian HP is developing. This is from the north or north-east into Scandinavia. There is already a good supply of surface cold. This is now being topped up with even deeper cold as I have already shown. HPs often sit over some of the coldest surfaces available. I feel that there is an excellent chance that once the HP sets up over northern Scandinavia, that it will maintain a similar position for quite a few days. The next thing is the LP areas on the southern flank. The very latest position on the live pressure chart shows another really encouraging sign – the central European LP is already helping to re-orientate the HP. I think that within 24 hours it will be far more on an east/west or east-north-east/west-south-west axis. This means a more direct easterly. The strength of this flow will be determined by the intensity of the HP and how close are the LP(s) on its southern flank. The increasingly cold air should then filter south-westwards in this flow. The south of the UK in particular may well be far enough away from the HP to the north-east to encourage some convective activity. If we can get sub -10c uppers in, then things could start to get much more interesting. For now, I would say just some snow showers on exposed east coasts but all to play for in the finer developments during the next few days. Next Weekend and Into Week 2: So how long will this last for and just what can go wrong. I know that some on here like to be more cautious and it can be wise to manage expectations to avoid future disappointments. Others can get taken in by all the ramping with the very bests charts greatly outnumbering the less goods ones being posted (I wonder why!). After all the disappointments we have seen so far this winter as well as in several recent winters it would hardly be surprising to see quite a few members taking a sceptical view. I believe that this will be a rare occasion when things might just go right for us coldies. This has been a highly unusual winter with persistent blocking restricting any Atlantic influence to the minimum. Blocked winters usually have prolonged cold spells. The vast majority of the blocking this winter has been MLB. This has allowed for some exceptional cold over Europe but we have mostly been just on the outer edge of it. There has been a highly anomalous area of HP very close to the UK for much of the last three months. Several posters have said if only we could have the HP a little further north. Well your wishes are about to be granted! I believe that there is now an excellent chance of HP being located to our north-east and later to our north or north-west for much of the next six weeks. Let’s have a look at the Jet Stream. The main arm has taken a more southerly track recently and the northern arm has broken up with a returning flow circling Scandinavia (which may help to maintain the HP or conversely, the HP is partly deflecting the flow of the Jet. Northern Hemisphere Jet Stream – Current Position: GFS 12z T+6 Moving on to D6, let’s have a look at several cross model Jet Stream charts. The main arm continues to be deflected to our south. The southern arm drives through the Mediterranean and south of most of Europe. This should carry LPs systems along that path and this will also help to underpin the HP further north. Northern Hemisphere Jet Stream for Sat 11th Feb – 0100 (with adjusted times to provide an accurate comparison): GFS 6z T+144 NAVGEM 6z +144 GEFS ens mean 6z T+144 Another useful indicator for assessing the likely future strength of the Jet Stream in the Atlantic is the thermal contrast between the eastern USA and the adjacent ocean. Right now and for at least the next week much of the USA will continue to have an unusually mild period. Canada is pretty cold but it rapidly turns milder further south. So, nothing here at all in helping to power up the Jet Stream. Northern Hemisphere Current 2m Surface Temperatures Northern Hemisphere Current 850s GEFS ens mean 12z T+0 GEFS ens mean 12z T+0 Northern Hemisphere 2m Surface Temperatures for 1300 Sat Feb 11th Northern Hemisphere 850s for Sat Feb 11th – 1300: GFS 12z T+144 GEFS ens mean 12z T+144 I have seen several poster’s concern over the chance of an Iberian LP drifting northwards over France and pulling in milder air with it. If the southern arm of the Jet continues to blow strongly through the Mediterranean there would seem to be a slim chance of this. In my experience, it is the slacker flows that can be prone to this. Even here, there are some examples of the milder air not being able to penetrate the surface cold and the warmer air is lifted over the cold which can produce far heavier snowfall or occasionally freezing rain. I call these events “cold southerlies”. They occurred repeatedly in the two epic winters of 1946/7 and 1962/3. In fact most often in the two Februarys. I’m not saying that the 2017 cold spell will be anything like those two winters but entrenched deep cold will take an awful lot to shift it – not a gentle push from the south. A Brief Look Further Ahead: I have not yet even mentioned the stratospheric changes and the multiple warmings in the Arctic. As I said in my report last Sunday (and repeated in several of my updates during the week) there was a good chance that even if the first warming fails to produce a true easterly that there would be one or two further opportunities. I was very reassured to see the latest updates from several of our strat experts like @chionomaniac that the PV should be split for a much longer period. In fact it may well be shattered! The MJO (see later) is predicted to enter its key phases through 6, 7,8 and 1 in the 10 to 15 day period. @Tamara, in her update today, maintained her view that the key background signals should all assist with much greater HLB. The result of this could be twofold, both are cold outcomes - either maintain and strengthen the existing Scandi block or encourage height rises towards Greenland with a broad Arctic flow established. In our longest cold spells we have sometimes seen several switches between easterlies and northerlies and back again. There could be a brief milder interlude during any transition and all the models have been struggling with this in terms of timing, extent and how long will it all last. I am going to stick my neck out and say that it will remain cold for the rest of the month (possibly well into the first half of March too) and it will be very cold for quite long periods. How much snow we might get is very difficult to for anyone to predict but the longer the cold spell continues the greater the chances. I am still very optimistic for the initial easterly to produce at least some of the white stuff. Can it all go wrong – yes it can but I feel that this is our best chance in four years for a memorable cold spell and there is so much positive evidence in favour of it. Now on to my routine coverage. Arctic Sea Ice News and Analysis: The last full monthly report was published on January 5th (next one due very soon). This is a fascinating read and includes a review of the whole of 2016. Please note that the current ice extent map and the comparison chart to the mean are updated daily and are always of interest. Here’s the link for the latest updates: http://nsidc.org/arcticseaicenews/ This chart shows the current extent of the sea ice (as on February 4th) in relation to the 30 year means. Source: National Snow and Ice Data Center (NSIDC) The “rate of recovery” during December was very close to a record and there has been a continued recovery (with several pauses) during January but, despite this, the overall ice extent is still at record lows and remains just below the previous low set during Winter 2012-13. Arctic Oscillation (AO) 14 Day Ensemble Chart: Here's the link to the daily charts: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml ...and here’s the current chart which updates automatically each afternoon: Note for newbies: The AO index reflects the amount of HLB in the Arctic. A positive +AO reflects very little HLB and a strongly +AO reflects no HLB anywhere in the Arctic. A negative –AO reflects some HLB and a strongly –AO reflects substantial HLB with more intense high pressure and/or more extensive HLB in various parts of the Arctic. This index produced by NOAA is based upon GFS model output and will fluctuate in line with that. Although ECM produce similar data based upon their own output this is not one of their “free-to-view” charts for public consumption. COMMENT (relating to the AO chart above when it was showing February 4th data - it updates automatically each afternoon): The Arctic Oscillation is currently negative and many ensemble members go into much stronger negative territory into week 2 (the strongest for the whole winter) but a smaller number of members trend back towards neutral. This reflects the GFS model uncertainty around D8 to D12. A possible switch to HLB and a northerly, a continuation of the Scandi HP or a breakdown with a milder Atlantic influence. North Atlantic Oscillation (NAO) 14 Day Ensemble Chart: Here's the link to the daily charts: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml (click on the small chart there) ...and here’s the current chart which updates automatically each afternoon: Note for newbies: A neutral NAO index reflects the close to average state of the mean sea level pressure patterns or the “climatological” norm in the North Atlantic. This would equate to the anomalous high pressure in the south, particularly around the Azores and low pressure stretching from off the eastern USA seaboard in a wide band running north-eastwards to the east of Newfoundland, east of Greenland and through Iceland. A positive +NAO occurs when these patterns are stronger than usual (eg: the Azores high is more intense or more widespread and/or the Iceland low is deeper or more widespread than usual). A negative –NAO reflects a weak Azores high and/or less intense Icelandic low pressure. A strongly –NAO would reflect a reversal of the normal patterns with relatively low pressure in the Azores and high pressure further north towards Iceland. A “west based –NAO” (talked about recently) is when the pressure is higher than usual in the western Atlantic such as around the Newfoundland area). An “east based –NAO would indicate higher pressure than usual in our part of the Atlantic. This index produced by NOAA is based upon GFS model output and will fluctuate in line with that. Although ECM produce similar data based upon their own output this is not one of their “free-to-view” charts for public consumption. COMMENT (relating to the NAO chart above when it was showing February 4th data - it updates automatically each afternoon): The NAO is currently positive and most of the ensemble members trend gradually towards neutral but remain slightly positive. Although we have the Scandinavian block much of the Atlantic is still dominated by LP. The NAO is not particularly important at this stage. If the block moves further west, we may see a slightly negative east based NAO later on. MJO Ensemble charts: Here are today's MJO ensemble charts for the big 4 (all updated on February 4th) + Kyle MacRitchie’s modified chart (by request following recent discussions) with the live links below should you wish to check any future changes: UKMO (7 day forecast): ECM (14 day forecast): NCEP/GEFS (14 day forecast): JMA (9 day forecast): Kyle MacRitchie (30 day forecast): UKMO: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ukme.shtml ECM: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml GEFS: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml JMA: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/jman.shtml Kyle MacRitchie https://weatherandvines.com/?page_id=140 and his explanatory notes and further guidance: https://weatherandvines.com/?page_id=128 COMMENT (relating to charts showing February 4th data - they update automatically each afternoon): What an amazing set of charts – a full house! The big 4 and Kyle MacRitchie all show the MJO entering the keys phases of 7,8 or 1 at very good amplitude. The best signals, I think for several years. A few of the ensemble members go off the chart in phase 8! This is perfect timing and along with the second (and possibly third) warming events should greatly assist with considerable HLB as we move through week 2. Over to our experts for a deeper analysis. Northern Hemisphere Snow Cover: I show animations for snow cover and sea ice changes. These are produced by the National Ocean and Atmospheric Administration (NOAA). When you go to their site you can change the date range and go back over 10 years. You can change the speed and pause on any particular day. These are brilliant, very informative charts and great to play around with. I’ve have re-set the links below to show the last 2 weeks from January 21st to February 4th but you can change these again on the site: a) Animated Northern Hemisphere Snow Cover Changes (updated by NOAA February 4th): https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/nh/20170121-20170204 ....and here is their current chart: b) Animated Europe and Asia Day Snow Cover (updated by NOAA February 4th): https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/ea/20170121-20170204 ....and here is their current chart: COMMENT: Part of central and much of eastern and south-eastern European is still snow covered. There continues to be well above average snow cover over northern Asia and this has expanded even further southwards and south-westwards – in fact it is quite exceptional. Scandinavia is fully snow covered, except the south of Sweden (the high central plateaus usually have pretty complete snow cover for most of an average winter). The extensive snow cover over North America has declined during the recent much milder conditions and this is likely to continue during the coming week or so The extensive snow cover over west Asia, Russia, eastern Europe and Scandinavia is another very important piece in the jig-saw as far as our forthcoming cold spell is concerned. This should greatly assist in getting the deeper surface cold in and maintaining very low temperatures for much longer – strengthening the block further. Current Arctic Regional Surface Temperatures: GEFS ens mean– Northern Hemisphere Current Temperatures for February 5th 1900 (12z – 1300 T+6): and here’s the link to live charts if you wish to view future changes (updated 4 times a day): http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=6&mode=1&carte=1 Here is my selection of Arctic Regional Temperatures: The the previous readings from my last full report are shown in brackets alongside North Pole: -20c to -24c (-20c to -28c). Baring Sea/High Arctic: -16c to -24c (-8c to -16c). Scandinavia: south -4c to -8c (mostly -4c); north mostly -8c (mostly -4c). Northern Siberia: -32c to -40c (-24c to -40c). North West Russia: -16c to -20c (-12c to -24c) North-east Europe: 0 to -4c (-8c to -12c). Greenland: -16c to -32c (-20c to -40c) Canadian Arctic: -24c to -32c (-16c to -32c). Alaska: -12c to -20c (-8c to -16c). Please note: For land masses I have tried to focus on readings away from the coasts and away from any mountainous areas. You can follow the trends by looking at the latest data at any time from now on. It is vital to note the time of day to take account of daytime/night time variations. So for like for like comparisons, for example the 1900 charts for each day should be available to view from the 12z (T+6) updates which are published around 1600 to 1700 or about 4 to 5 hours later. Svalbard Daily “Maximum” Temperature Forecast for 10 Days: Here are the links to the 3 Svalbard stations that I am monitoring together with a summary of D1, D5 and D9 values: Central/West Svalbard – Longyearbyen 28 m asl: http://www.yr.no/place/Norway/Svalbard/Longyearbyen/forecast.pdf February 6th +3c; February 10th +1 c; February 14th -5c. North-West Svalbard – Ny-Alesund: http://www.yr.no/place/Norway/Svalbard/Ny-Ålesund/forecast.pdf February 6th +2 c; February 10th +1c; February 14th -5c. Central South Svalbard – Sveagruva: http://www.yr.no/place/Norway/Svalbard/Sveagruva/forecast.pdf February 6th +2c; February 10th -2c; February 14th -8c. Please note that the links above will update automatically at frequent intervals throughout the day. They are the Norway met office’s predictions. We need to be aware that these are only a forecast that is subject to change and I am told that the Arctic surface temperature forecasts are not completely reliable even at quite short range. BRIEF COMMENT: Temperatures have risen just above freezing during the last few days with one of the warmest periods of the winter. This followed one of the coldest periods in the previous week (even below the 30 year means). The southerly winds brought quite a bit of snowfall with more to come. It is only after next weekend that temperatures are set to fall again. To put the above figures into context, here is a link to the main Longyearbyen site: http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html This shows monthly means and actual highest/lowest temperatures recorded during this winter and goes back further. Svalbard has been seeing “maximum” temperatures often running at 8c to 10c above their long term average throughout most of 2016. This has been the pattern for several years and is reflective of the warming Arctic and record low sea ice cover. Final Comment: As I’ve already said, I am extremely positive about the forthcoming very cold spell. I feel that there is a good chance that this will last for at least 2 to 3 weeks and perhaps well into March. Now will I be eating humble pie next weekend – I do not think so! Next Update: My next full weekly report should be on Sunday evening, February 12th.
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    One final post before bed. I am going to eat some humble pie and give huge praise to Tamara because I am afterall fair. I have been looking at some previous model runs and posts on this thread for the period 29th Jan. Look at what the GFS was predicting for tomorrow on the 29th Jan. This is what Tamara said on the 29th Jan. "However, the upstream jet, is set to decelerate rapidly as pressure rises over the Pacific and re-build the Aleutian Ridge. In the Atlantic sector, the retrogression of the pattern will tend to angle the Jetstream more NW/SE and, conceivably, enable build of pressure over Scandinavia. With time, as the disrupting trough gets separated from the Canadian lobe of vortex, downstream amplification from the Pacific sector becomes possible at the same time as the wave 2 response is activated by rising pressure over Scandinavia to work on the vortex in tandem with the Aleutian Ridge. It is key at this point that the vortex is sufficiently weakened to allow the bleeding of secondary systems to be cut off from the Canadian lobe - and hence terminate the thermal gradient." https://www.netweather.tv/forum/topic/87058-model-output-discussion-25th-jan-the-final-third-of-winter-beckons/?page=12#comment-3534098 Astonishing forecast and I cannot give her enough praise.
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    Knee-jerk, a joke!?...if that is what you believe then simply don't follow. I was simply highlighting what the EC ENS are showing and to be honest certain people need to read before commentating, perhaps it's about time to stop sharing that info as clearly people don't know how to interpret it correctly. Also this is what I put in the latest blog and quote; "So, as things stand I do believe there is a good chance that at some point during the second half of February, perhaps into early March too that a Greenland block may well make an appearance with perhaps cold weather arriving from the north or north-east, one to definitely keep an eye on as the final third of winter progresses and for those looking for some early Spring weather could well be disappointed." Second half of Feb or into early March, not by the 17th! Matt.
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    Yes, I recognise these sage pieces of sentiment so well. The signals are always wrong, and the professionals (and others) who try to present and explain them, when an operational appears to take away your virtual snow Remember the snapshots in time. Speaking for myself I won't write another book about that. Also remember that the last weekend in January suggested another two turgid weeks of Atlantic driven cyclonic tramlines. The upcoming period was picked up in the ashes of that ahead of NWP and the models have turned around and run with it. The likes of BB62/63 has spent the best part of three weeks (since the demise of the previous cold snap) documenting the apparent decline of the European cold and its expected return. This approach, along with technical information provided by a wide raft of other posters has not been far wrong at all at this type of juncture, so some slack could be afforded instead of stamping of feet. Then of course there is also the small matter of Mr Hammond and the professionals.... It would be easy to sit and wait for each operational and ensemble suite and chop and change opinions each day from those. Safe that way for sure and can't really go wrong. Each to their own of course, but for some it is good to expansively push the boundaries. However, the outlook for the next week, let alone the rest of February is not going to be decided by one or two operational or even ensemble suites. Snapshots in time, and look at how many snapshots in time have already occurred. There is very much a retrogression signal in play as previously suggested would appear the other day. I'm afraid its a wait to see how things pan out, but lets deal with the unfolding cold advancing across Europe first and let those details consolidate without flapping 4 X per day. I might have one eye myself on the next step ahead, but I'm not going to take the other eye of any of the possibilities in the coming days. Its good to actually be aware of the weather out of your window, and not just the maps 4 x per day on your computer screen
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    Evening All - So So many discussion points this evening- where do we start? Ive skim read the MOD thread this evening & lots of inputs with many differing angles of personal perspective - FWIW heres mine... In no particular order - * Snow & snow cover in late feb / Early March is an odd discussion point cropping up today & in terms of the reason why snow doesnt fall or even doesnt lie or does / doesnt melt - The time whether it be early feb or late feb actually makes some difference- but its not the important factor, & anyone really putting at ththe forefront of their worries need not be 'to' concerned- If we consider a starting condition over say Milton keynes on Feb 1 then replicated the same atmospheric conditions on Mar 1 I would hazard a guess that the potential Maximum temperature would differ by 1/1.5c tops- So, the maximum temperature change across the month & slightly longer daylight hours would aid a longer period of sublimation - maybe an hour more- pro rata- maybe another cm of snow V early feb ( if we had it lol ) Ahead of this though is other more crucial factors * Soil / Ground temps pre snowfall are certainly indicitive of fast snow melt if very mild weather precluded snowfall * dewpoints are critical when it comes to melt - you could lose a couple of cms in a sunny easterly with dewpoints sub zero or loose inches in mild +5c dewpoints from the SW - ( although mega low dewpoints do increase sublimation again- but we dont really get that !) * Also weather type has an influence- rain will melt snow faster than sun ! So for the UK ^^ if we do finally even get snow in Winter one of the above usually isnt far behind ( or ahead ) to melt our snow no matter what time of year it is... Onto the models tonight - On what appears a mixed bag however really I dont see to much divergence across the piste... The strong positives are: -To see Scandi High continually modelled in the same ( more or less location ) & not drifting south to become a sceuro High - No SE Scandi shortwave spoiler becoming a limpet on the coast - Importantly looking through the detail, the medium to long term looks very very blocked with the GFS keeping a continental flow from 168 all the way to day 16 & beyond So whether we get the cold or deep cold straight away it appears that across the piste it should only be a matter of time behind we see some snow from this 'evolution' The 'opportunities' * I think we have gained real clarity tonight that cycle 1 as suspected would just be to much for the UK to hope to get into continental air - the western edge looks like it will land close to holland before holding in situ as cycle 2 works through the UK, I guess this isnt a negative so much as 'it was a bonus if it happened' so our real prospect of cold from the east / South East I would say increases post day 6 - With wednesday earmarked as the 'start' of cycle 2 .... The UKMO / GFS blend here sees a very deep upper air cold pool in central europe by then, the uppers at the top end of the core -16, bottom end -24 depending on the original flow allignment out of the pole- Cycle 2 will throw the atlantic at us, we must expect this, we 'should' expect to the azores high throw a ridge NNE as thats the process- the key being what energy goes underneath as opposed to lifting out - ECM is the most eastward solution @144 , this is because the upper air cold pool was poorly alligned at 120 to repel the atlantic push - Where as the UKMO was much better with the allignment allowing for cycle 2 to be almost a battleground- ECM by 168 the atlantic is lifting out & energy is nicely split so the ECM then never allows the atlantic back in- UKMO 168 is very similar by starting to pull back the Easterly flow as the atlantic 'lifts' out- The GFS sits in the middle - a bit like the shortwave does over the UK ! I think FWIW the ECM is to progressive tonight - very much the same as it was x2 days ago before backtracking ... UKMO looks spot on, although I think the upper air cold pool is to deep & the CAA we see over the continent at 120 is a bit fast & isobars to close- but overall UKMO looks again to be my run of the day in terms of a forecast- In a nutshell, Cycle 1 throws the cold deep westwards into europe but doesnt make it, Cycle 2 spanning another 24-36 hours will really drive 'some' cold west but how much is the key & what allignment will the winds be... An enjoyable period of model watching, probably the best since 2013 !!- S
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    Upstream amplification in the Pacific. Yep Pressure build over Scandinavia. Yep Split vortex assisted by Wave 2 action Yep Downstream amplification? Yep - just coming into day 10 period So we move onto the next part of the jigsaw. The eastward propagating tropical signal has been well documented by others today. With the downstream amplification signal becoming increasingly advertised within NWP suites from the day 10 period then we have the double lock scenario that has been AWOL so far this winter in terms of potential ambush from both NE and NW vectors. The amplification key in drawing cold air advection westwards and leading to the prize in the extended period Yes indeed obviously expect changes in face value intra suite operational detail - but that applies whatever the synoptics However the models are far from clueless. They are reading the script perfectly - see above What is key is that the downstream amplification posse is clearly coming over the hill at day 10 into complete model ensemble suites. Look at the wider hemispheric model plots and see the retracted Atlantic ridge providing the ambush of the troughing from the west to squeeze the vorticity energy out, while the continental influence bumps it from the east. The intra model operational details do not matter a jot at this stage within that time as long as the polar field and NE Europe is modelled the way it is. The jet deceleration downstream will take care of itself as the amplification comes closer into model radar. Then, just perhaps, we can start to think about the prize So far, so very very good Edit: Thanks Mr ECM ! The pincer ambush of the Atlantic energy c/o expected downstream amplification perfectly illustrated by 12z ECM - which allows a glimpse of the prize as the deep cold is then backed westwards...
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    Morning A lot of ECM lemmings here this morning -perhaps many missed last nights post showing that it has been terrible in the last 5 days - classic really in being over progressive... let things develop- every day as things have got closer the uppers have got modelled colder - even the ECM has a pool of -9 air pushing SW into wales & the NW at day 5-6 yet people worried about day 8/9/10 so much flapping on here this morning the forums going to take off...
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    Copied for intended emphasis and perspective of just how far we have come in several days Insistence that the Azores High would not prevent the easterly vector in the medium term period has prevailed a suggested. Almost insidiously, each ensemble suite for the medium term has got colder as it has come within the 3 to 5 day period. The process is still continuing - its only over focus on face value operational variances and worrying about micro details at ranges that are going to change dozens more times yet that blur the reality and make this a less enjoyable experience than it should be The GSDM continues to provide both forward guidance and also show solid background support for NWP to rollout an increasingly higher latitude programme as we head through the month In the Pacific we have the enticing prospect of a tropical convective wave that has been gaining suggested forecasting amplitude in recent days, and this has a lot to do with why we should expect upgraded prospects for amplification and Atlantic energy sliding southwards under the block to the NE. The latter as underpinned by the stratospheric rationale that ED/chiono and others have provided. So what evidence is there for increased amplification prospects from tropical and extra tropical forcings? The eastern portion of the ENSO zone has been undergoing some very impressive warming as the beginnings are in place towards neutral to weak El Nino in 2017. This warming provides compellingly good support for the prospect of intensification of the MJO through Phases 7 and culminating in Phase 8. The stronger the forcing at its more eastward, the greater amplification potential and prospects for cold air advection. A strong Phase 7 to 8 orbit suggests the most intense downward repercussions are maximised in our Atlantic and European sector. Also cloudiness, (as an obvious flagger of increased convection potential) has been increasing close to the dateline -.see the diminishing yellow shading, indicative of rapidly declining OLR. Further signs that the Pacific is becoming more and more conducive to adding westerly winds to the planetary atmospheric system. The importance of these westerly winds, is that with co-operation from the extra tropics in the form of mountain torques they can propagate and eddy poleward to assist mid latitude < graduating to higher latitude blocking. The effects of eastward moving tropical forcing is already impacting frictional torque and translating to the start of a bounce in relative atmospheric angular momentum. At the moment what has been holding this back a little is the protracted -ve mountain torque over the Rockies. But this in itself helped set up the changes we are seeing as posted last week. But on the basis of the suggested size of the upcoming Pacific signal we should expect a large Asian torque response - also good news for extra vortex punishment. This will be the second part of sucker punch from the atmospheric circulation that was suggested to be programmed for the extended period as far back as last Sunday - when the NWP models were still highly cyclogenesis and zonal orientated moving forward. Its been catch up ever since. With all this in mind, the Global Wind Oscillation is already being indicated to attain a higher amplitude Phase 4 by the usually low AAM bias GEFS. Taking into account the backdated two day lag from WDT (a highly accurate site depiction of the tropical and extra tropical wind flows as registered by the GWO) increasing amplitude through Phase 4 began with the turn of the month A GWO orbit through Phases 5,6,7,8 seems reasonable with interesting synthesis of both tropical and extra tropical forcings coming together to create a strong wind flow signal for retrogression of the block and advection of deeper cold uppers tucked up over the Urals. The two day lag of the data means that these really solid amplification signals will be appearing over the coming days. But suffice to say, it would be best to take extended attempts to remove the block and send energy over the top with a very large truck load of salt. The evidence is stacked against this, and suggests the converse holds much better logical persuasion. So there is a test provided to those who nerves must customarily oscillate with the face value nuances of each and every NWP roll-out..... Later edit: To back up above ^^ updated AAM tendency taking off further (still two day lag)
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    I hope you guys realise I'm sacrificing my roof in order to set up your easterly.
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    sorry for this post but these over the top tweets that change like the wind have been a real blight of the winter model threads this winter..people hanging on every tweet and then posting it like its the gospel really has got to me this winter.. they change more often than the GFS has model runs..i think we should have a thread just for tweets... call it "tweets that never happen" thread..?? not a swipe at you Summer Sun in any way just frustrated with the constant stream of tweets saying this that and the other and none of it ever being anywhere near what happens etc..
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    Seriously, that's four of the first 9 posts into this thread removed for being just moans and therefore totally off topic. There's a note at the top of the thread about this, and countless reminders have been posted by the team, it's to the point where those continually ignoring all this, and just posting whatever they like in this thread must be doing so deliberately which shows zero respect for others in the community. So, next step will be to tighten up again and start blocking people from posting in here without further warnings.
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    DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 6 THE COLD POOL MOVES EVEN CLOSER In the build up to our cold spell, I feel that it will be useful to keep up-to-date with the current and trending temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next few days around 0730 (although I am away on a business trip this Friday so no update then and Saturday’s will be around 1300). This will show how the pattern is evolving and allow us to monitor the extent and the severity of the cold that we might expect. Now, I shall pick up from my last “check” on page 132. This took us to February 7th. European Surface Temperature Charts: Current "live" Feb 8th 0650 Feb 7th 1250 Feb 7th 0650 Feb 6th 1250 Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to maximums. COMMENT: The pool of "deep" cold only changed slightly during the last 24 hours. The sub -20c temps (purple) has moved slightly southwards and slightly westwards. Scandinavia has become considerably colder with purple colours appearing there. Some of the purple colours just to the east of Scandinavia and on the north-west Russian coast have been replaced by the black sub -12c temps. This slight warming is simply due to the airflow there coming off the sea around the top of the HP. The better news is that the pool of sub -12c temps has moved westwards through eastern Europe and now across central Europe too. The area of sub -8c temps (dark blue) and sub -4c temps (mid blue) ahead of this have also moved westward. All this can be seen by comparing the two "0650" and the two "1250" charts. GFS 0z February 8th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps COMMENT: Compare today's charts (above) with yesterday's (below). Note the further expansion of the "purple shades" area of sub -20c surface temps with a similar area of sub -24c temps and a wider area of sub -28c temps (pink) and sub -32c temps (light grey) in the north-east of the block. I estimate that the whole purple area in around 300 miles further south but only marginally further west. Scandinavia has cooled down with an expansion of sub -20c temps there. The sub -8c temps (dark blue) have reached central Europe and sub -4c temps (mid blue) have progressed further south-west ahead of this. Overall the huge pool of 850s with sub -8c temps has expanded but the area of deeper cold has changed little. The pool of sub -20c 850s has, perhaps expanded very slightly but only in the far north-east. The region of -12c temps is slightly smaller in the main pool. There is still the area of breakaway sub -12c temps (with a centre of sub -16c temps over Sweden) which has continued to move slowly westwards and has now reach the North Sea. The sub -8c temps have now extended to eastern UK and the -4c temps now cover most of the country with the greens (over 0c) now far to our south. GFS 0z February 7th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps European Surface Pressure Charts: Current "live” Feb 8th 0650 Feb 7th 1850 Feb 7th 0650 Feb 6th 1850 Current Met Office Fax: 0600 Feb 8th GFS 0z February 8th T+6 GFS 0z February 7th T+6 COMMENT: The good news is that the Scandinavian HP has moved very little in the last 24 hours just edging slightly north-westwards and it is now centred over east Sweden. It has continued to slowly but steadily intensify. The pressure reached 1051 mb overnight but the highest reading in central Sweden is now (at 0650) 1054 mb. Yesterday, I estimated that it would end up with a central pressure of 1055 mb later today and it is on course for at least that. The models are still playing catch up with this and under estimating the strength of the HP. It is slightly further north-west than most of the models have indicated - this is good news. There is no powerful Jet Stream to shift it away quickly. I feel that it will more or less maintain its position for longer than currently indicated (see next paragraph). The slightly less good news is that the HP still has a ridge to the south-east. This means that the very cold surface air has a longer path to drift around the southern flank. As the HP is still building in the north-west it may lose that south-east ridge which would then open the floodgates to a more direct flow. So minor changes might make quite a difference. Another bit of good news is that the lower heights to the south has expanded. There is now a broad band of LPs stretching across most of the Mediterranean. Significantly, pressure has been falling over the Black Sea. The pattern of LPs looks very conducive for propping up the HP, should somewhat strengthen the air stream in between and as the bulge of LP currently towards south-east England moves south we may yet develop a more direct easterly than has been indicated. The next 24 hours will be very interesting. Looking ahead into week 2, the HP is predicted to sink southwards. @Nouska made a good point last night on the "quiet" thread, that the main reason for its southward movement will probably be due to the PV shifting east towards Siberia next week. The lower heights from the north would do this and this would be good news in due course with HLB building towards Greenland and lower heights into Scandinavia as the pattern transition to phase 2 of the cold spell gets underway. (EDIT: this HLB later on in week 2 was reflected in the strongly negative -AO ensembles yesterday but remember this is based on the GFS model output and will fluctuate until it and other models start to build in the very favourable background signals much more consistently). Several models did indicate this but several others sink the HP without any eastward shift in the PV. This would seem to be illogical. I believe the HP will be very resilient and will only give way when (and if) the PV movement gets well underway - so perhaps rather later into next week. Overall, more progress but at a slower pace. ADDITIONAL COMMENT: I have just had a chance to look more closely at the 0z model output. This is so illogical, that I cannot accept it. I have banged on about the Euro cold block for over 6 weeks now. The models have been dreadful in factoring in the persistence of this block even when we had a powerful Jet Stream. By this weekend, the block will be further west, much more extensive and more intense than it has been at any time this winter. It will take a great deal to shift it. The Atlantic is extremely weak. The favourable background signals will be the powerful driving forces during the next few weeks. The latter part of the strat warming impacts, probably the PV migrating to Siberia (rather than a split vortex) and the MJO set to be in its most favourable phases and strongest amplitude since March 2013. At worst we will see a less cold (possibly slightly milder in the UK) interlude during the transition but not for "all" of Europe. Finally,, south-south-easterly winds will NOT be mild - read my post last night on this. The models almost always under estimate surface temperatures under slack or quite high pressure following a cold spell. Show me a powerful Jet Stream firing directly towards us and I'll back down on my strong opinion!
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    A highly encouraging morning to continue the progress of yesterday evening Remember the checklist timetable: The amplification heading downstream into the Atlantic draws the Azores High westwards and squeezes out the energy bleeding from the Canadian lobe of the vortex in the 7 to 10 day timeframe. It is thereafter where cold air advection is most likely to occur. The NH charts in the model suites continue highly consistent with this process- mean charts at that distance are going to blur the signal out. However, even in the period before this, the modelling of the heights to the NE and associated cold pooling is going to be problematic to model - especially with the spawned low pressure systems heading on a southerly track and hitting a veritable brick wall. This process gets more and more prone to error and miscalculations the closer the time period gets to where the Azores High retrogresses and is consequently less and less able to positively tilt the energy NE'wards. On that basis any ensemble suite clustering taken in isolation at face value today is simply a snapshot in time, and really needs to be assessed based set against the likely upstream evolution. The timetable itself - and when and where amplification is most likely to occur. As long as the amplification signal remains, (and it needs to be watched to ensure it does), then the cold air advection and adjustments west of the pattern will grow in the ensemble suites We cannot guarantee the prize to pinpoint the UK, but the larger pattern has all the ingredients in place to make it happen - and after all it has been possible already to identify the possibility a prize coming over the horizon by looking at the GSDM weighted against on-going stratospheric destabilisation at an apparently most unlikely time when the models were churning out seemingly endless cyclogenesis horror only last weekend Aside from the usual obvious caveats and guarantee disclaimers, there are more reasons to support cold evolutions than to dismiss them. There are only a few weeks of official winter left, so worth coming off any fence while there is nothing to lose and plenty possible to gain
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    If its good to have a debate, then here is another side to it I really don't know where "dignity" comes into this. Who, exactly, loses dignity by attempting to identify evolving weather patterns based on the best data that is available to them? I will speak just for myself here, but the only really significant optimism I have expressed this winter, at least since the early promising signals dissipated in late autumn, only began in late January. Such that TEITS was kind enough to mention the other evening Objectivity should always apply to model discussion, irrespective of outlook, but fortunately late January supported a cold(er) synoptics to evolve - and a colder synoptic pattern that wasn't apparent in NWP at the time. So it was fortunate because it meant that forward thinking could jive with the mood of the thread. As I found earlier in the winter, its very much harder to post and appear to move against the general mood of this environment, appearing as some kind of kill-joy, when individual thinking is not the same. Many on this model output discussion thread root for a similar outcome, very much including myself, but I would suggest the premise of some of these protest and frustration posts work the other way around - and it is not those who try to understand the chaos of the weather patterns who need to reign themselves in to retain "dignity" but maybe instead its the case that some sections of the audience should temper their expectations to the science of meteorology which does not evolve weather patterns soley to accomodate the wishes of that audience (which I tried, and failed, to suggest yet again yesterday evening) I wholeheartedly agree that the surface conditions are a disappointing reflection of the synoptic pattern, but I'm increasingly often at a complete loss at what some people's expectations are on this thread sometimes. If the expectation is to never let the audience down by not only seamlessly reel in a freeze to t0, but to also ensure that the delivery optimises deeply cold uppers and unstable convective snow showers piling in from east to west (or north to south) to satisfy everyone to no exclusion - then frankly this thread should be closed down from November to March Its always the so called "analysts" or alleged messengers of a given weather pattern that are wrong or who need to go back to drawing board when the weather outside the window doesn't mean those lofty expectations. Its not just the weather that is cursed at the end of a frustrating winter in the UK, its also the messengers. From the ordinary member on here, to the qualified analysts of weather organisations, right through to national institutions like the METO There are ways of venting understandable frustration, and frustration I share at what could be, but their are much less emotional and blame driven ways of doing so. In that respect I look forward to the longer days. The virtual in-house bias turns to warmth rather absurdly like the flick of a switch once meteorological winter is finished, but even the UK's unerring ability to deliver cool showery weather around the longest days of the year, and which meets with the summer equivalent of winter ice and snow starved stamping feet, is at least relatively easier to manage.... Edit: If anyone wants to read a good attempt at deciphering the loss of expected amplification and HLB signal related to Pacific progression of tropical convection, then @Singularity has I think made some worthwhile analysis in the technical thread
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    Only just catching up with all the outputs today. Good to see the ECM finally getting to grips with the MJO signal, so it looks like a short less cold interlude after a colder spell then a north/ne flow likely developing as pressure rises over Greenland. Not sure where all the gloom is coming from , the easterly was never forecast to be a throwback to the 80's. No output in the reliable timeframe had some deep cold hanging on for more than a few days. This is the problem with easterlies that they take on a reputation which doesn't often match the expectations only in rare cases. Whats shown is what was realistically expected and any less cold interlude will be short and likely to be shortened further .
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    DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No.4 GREAT NEWS - THE COLD POOL INTENSIFIES AND IS PUSHING DIRECTLY TOWARDS THE UK In the build up to this week’s cold spell, I feel that it will be useful to keep up-to-date with the current and trending temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next few days. This will show how the pattern is evolving and monitor the extent and the severity of the cold that we might expect. Now, I shall pick up from my last “check” on page 92. This took us to February 5th. European Surface Temperature Charts: Current "live" Feb 6th 0650 Feb 5th 1250 Feb 5th 0650 Feb 4th 1250 Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to the maximums. COMMENT: Wow! The is happening even more quickly than I was expecting. The area of deep cold (purple) over north-west Russia has intensified, expanded and is moving steadily south-westwards towards Europe. The area of light and darker blues has extended into central Europe. All this can be seen by comparing the two "0650" and the two "1250" charts. Just watch the deep cold moving into north-east Europe during today and then further south-westwards over the next couple of days. GFS 0z February 6th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps COMMENT: Compare today's charts (above) with yesterday's (below). The "purple" area of sub -20c surface temps has expanded and strongly intensified. There are now sub -24c, sub -28c and sub -32c temps (white) showing in north-west Russia - this pool is spreading steadily south-westwards into northern Scandinavia and north-east Europe. The pool of sub -20c 850s has also moved steadily south-westwards. There has been a expansion of the sub -8c in Europe with a break away small pool of sub -12c over the Baltic Sea. This is all marching towards the UK with sub -4c just arriving on our east coast.- all the greens have disappeared. Notice the now perfect orientation of the whole pool aiming right at the UK. GFS 0z February 5th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps European Surface Pressure Charts: Current "live” Feb 6th 0650 Feb 5th 1850 Feb 5th 0650 Feb 4th 1850 Current Met Office Fax: 0600 Feb 6th GFS 0z February 6th T+6 GFS 0z February 5th T+6 COMMENT: There it is - our beautiful Scandinavian anticyclone! Note how quickly it has intensified - currently (0730) 1043 mb and still rising steadily. It is also still slowly moving westwards. As I said yesterday, the LP to the south was already undercutting and supporting the HP block. The HP is taking on the perfect shape with its ridge towards us and the flow on its southern flank now backed from south-eastery to easterly. This pattern could not be any better. Perhaps some of the more sceptical amongst you might now see that my very bullish slant in my full weekly report yesterday (on page 105) was completely justified. The charts above show that this cold spell is going to be something very special and is developing even more quickly than predicted.
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    WINTER 2016/17 FULL REPORT No. 11 WITH JANUARY 29th INPUT Please note I am still learning how to cut and paste various types of charts into my posts so please bear with me as I increasingly use these in future reports. Review Of The Last Week – A Big Pattern Change: After over three weeks with the European cold block holding back the Atlantic, we have finally seen it breakthrough. Several days ago, we saw minimum temperatures as low as -8c in the south-east and many locations had an ice day on Thursday with maximum temperatures in several locations around -3c. At the same time, parts of northern Scotland registered around +12c. Yesterday and this morning we have seen a complete reversal, with a few parts of the south registering +12c while several locations in the Scottish Highlands recorded below -3c last night. The HP and surface cold was pushed eastwards and the transition is almost complete with the remaining cold air in the north exiting the UK during the next two days, although temperatures are not predicted to be as high as further south for a while yet. The UK as a whole is on course for a milder than average January and this will probably be reflected in the Central England Temperature set too. This masks the regional picture. While much of the north has seen some very mild conditions at times, the far south and south-east has been colder than average, especially for the last fortnight. Some areas have received their first significant rainfall since early January and almost all the country has been drier than average. The Current and Short Term Position: The high pressure is still hanging on across western Russia and eastern Europe and ridging towards central and southern Europe and much of central and eastern Europe is still under the cold block as can be seen below: Current European Surface Pressure “Live” European Surface Pressure at 1250 Current European Surface Temperature “Live” European Surface Temperatures at 1250 Just how far eastwards will the block be pushed? Much will depend on the direction and the strength of the Jet Stream. All through this winter I have noted the debate on the MOD regarding the pros and cons of a re-set vs fending off the Atlantic. A re-set would involve the block being completely broken with a period of more zonal conditions pushing right through Europe. This might allow occasional Polar Maritime and brief colder incursions in between milder and wetter periods. In due course, a colder pattern “might” develop but the risk is that we might face mild and stormy conditions for weeks on end (I am writing this from a “coldies” perspective and not yet taken account of the impacts from a possible SSW). On the other hand, retaining the block prevents any zonal spell from becoming established and might allow for a much colder evolution with a spell of easterlies and/or northerlies. The risk here being that any significant cold might come close but not move right over the UK, just as we have seen in recent weeks. It is highly unusual to have so much MLB and so little really cold weather. Now how about a third option – the score draw with the best of both worlds? We can achieve a re-set with the block held further east. This will allow an Atlantic flow over north-west Europe and the UK. If the block (over eastern Europe and western Russia) continues to provide a significant cold pool, perhaps with a top-up from the north or east, it will still be close enough to tap into if the right synoptic pattern develops. Low pressure might develop over the Mediterranean and/or move just to the south of us. This might allow heights to build to our north-east and advect some really cold air into the UK. Alternatively, fronts might stall over us and a real “battleground” pattern develops - not with just surface cold but with much deeper cold mixing with the milder air to our west. I believe that this “middle” scenario is quite possible. I’ll demonstrate it with one of my cross model analysis looking at D6 based on last night’s 0z or this morning’s 6z output – which was the most currently available at the time of writing this part of my report (around midday, Sunday) but when this goes live early this evening, most of the 12z output may well be slightly different. Northern Hemisphere Pressure for Sat 4th Feb – 0100 (with adjusted times to provide an accurate comparison): GFS 6z T+138 ECM 0z T+144 UKMO 0z T+144 GEM 0z T+144 NAVGEM 6z T+138 JMA 12z Jan 28th T+156 GEFS ens mean 6z T+138 Met O Fax 06z T+120 for 1200 Thur Feb 2nd The recent output has fluctuated slightly during the last few runs (not unusual for D6 and beyond). The main differences are just how much HP is retained to the east. The ECM shows greater heights maintained to the east and on their 0z run this eventually evolves towards one of their now famous D10 easterlies! The GFS 0z showed far less HP to the east but the 6z did back track on this to some extent. The other models generally fall in between these two positions. Northern Hemisphere Jet Stream for Sat 4th Feb – 0100 (with adjusted times to provide an accurate comparison): GFS 0z Mon Jan 30th T+120 NAVGEM 6z T+138 JMA 12z Jan 28th T+156 GEFS ens mean 12z T+132 The predicted path of the Jet Stream is very interesting. The most progressive, the GFS, shows one arm just about reaching the UK but diving south-east into Europe and across southern Europe with nothing pushing into central Europe. There is a much weaker and fragmented northern arm skirting north and around Scandinavia. The GEFS ensemble mean and the JMA are similar but with the main arm slightly further south while the NAVGEM shows it even further south. ECM do not produce a free-to-view chart but it would be interesting to see how they model the Jet Stream for the same period. I will not look at any detailed output for the far less reliable week 2 period but there is continuing divergence - one direction fires up the Jet more strongly and straight at us while another shows it continuing to split and avoid much of Europe. I would say that next weekend might be a crucial period in dictating just how dominant the Atlantic will be during the first half of February. UPDATE: My charts for GFS and GEFS ens mean had updated to the 0z (Monday, Jan 30th) and 12z runs respectively (I must have made an error in saving the images) - so I changed them to the T+120 and T+132 for consistency. In just 12 (and 6) hours, they have both moved towards the earlier NAVGEM chart, with the Jet slightly further south. Another useful indicator of the strength of the Jet Stream in the Atlantic is the thermal contrast between the eastern USA and the adjacent ocean. Northern Hemisphere 2m Surface Temperatures for Sat 4th Feb – 0100: Northern Hemisphere 850s for Sat 4th Feb – 0100: GEFS ens mean 6z T+138 NAVGEM 6z T+138 GEFS ens mean 6z T+138 NAVGEM 6z T+138 There is a moderate contrast with some colder air over the states but most of the coldest air is further north over eastern Canada and around Newfoundland. Again, the NAVGEM shows slightly less extensive cold, reducing the contrast. Unless the cold in the eastern USA becomes more severe and extensive, the thermal contrast is well below what it can be and might not play a significant role in assisting the strength of the Jet Stream. Other factors might be more dominant. Any changes in this contrast, the strength and direction of the Jet Stream and whether it continues to split and meander need to be monitored during this week as they could well be very influential on the week 2 pattern. A Brief Look Further Ahead: If we do see a stormy spell during week 2, as some of the recent output indicates, this does not necessarily mean mild. In fact I agree with @johnholmes in his post this morning that temperatures will be close to average in the south and it might be rather cold in the north. There will be short periods of mild and wet weather in the warm sectors followed by colder incursions during periods of Polar maritime air. This would give snow over high ground and especially where they need it in Scotland. If the Jet Stream continues to take a more southerly route, there could well be secondary depressions moving over southern England or even to the south of us at times with possibly some brief more widespread wintriness. If something closer to the 0z ECM evolution verifies, then a full undercut is quite possible with the eastern European cold pool advected towards us. So,plenty of interest just in the next 10 days to 2 weeks. Let’s have a quick look at the full 2 weeks with the ensemble chart for London London 2m Temperature Ensembles 0z January 29th to 13th February: This very useful ensemble chart highlights the current (Sunday 0z) differences in the model output. Both the NCEP and ECM start off on the mild side (after a slight frost tonight) but show temperatures closer to average later this week. Then from around next weekend the ECM shows colder nights than the NCEP. After a very mild day on D9, the ECM starts to trend below the mean on D10. The NCEP also shows a generally less mild (or colder) week 2 but it's still above the mean. The ensemble members, as they tend to in the less reliable period, really diversify with some showing generally colder conditions while others remain nearer to average or on the mild side. The next week will be a really fascinating one to watch for developments. Then we have the “possible” SSW (Sudden Stratospheric Warming) and its impacts from mid-February onwards. I’ll leave that for others to focus on until there is greater certainty of the warmings and what might follow. UPDATE: While I have spent much of today writing this report, I see that the 12z output is more encouraging with some movement towards the 0z ECM evolution. I also see that there have been some great posts this afternoon, including those from @chionomaniac and @Tamara adding to the encouragement for an interesting February. Now on to my routine coverage. Arctic Sea Ice News and Analysis: The last full monthly report was published on January 5th. This is a fascinating read and includes a review of the whole of 2016. Please note that the current ice extent map and the comparison chart to the mean are updated daily and are always of interest. Here’s the link for the latest updates: http://nsidc.org/arcticseaicenews/ This chart shows the current extent of the sea ice (as on January 28th) in relation to 30 year means. Source: National Snow and Ice Data Center (NSIDC) The “rate of recovery” during December was very close to a record and there has been a continued recovery (with several pauses) during January but, despite this, the overall ice extent is still at record lows and remains just below the previous low set during Winter 2012-13. Arctic Oscillation (AO) 14 Day Ensemble Chart: Here's the link to the daily charts: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml ...and here’s the current chart which updates automatically each afternoon: Note for newbies: The AO index reflects the amount of HLB in the Arctic. A positive +AO reflects very little HLB and a strongly +AO reflects no HLB anywhere in the Arctic. A negative –AO reflects some HLB and a strongly –AO reflects substantial HLB with more intense high pressure and/or more extensive HLB in various parts of the Arctic. This index produced by NOAA is based upon GFS model output and will fluctuate in line with that. Although ECM produce similar data based upon their own output this is not one of their “free-to-view” charts for public consumption. COMMENT (relating to the AO chart above when it was showing January 29th data - it updates automatically each afternoon): The Arctic Oscillation is currently positive and then trends down closer to neutral by next weekend. Then week 2 is much more mixed with some ensemble members trending positive but rather more going negatively with several going strongly negative. So, uncertain but perhaps a sign of some HLB later next week. North Atlantic Oscillation (NAO) 14 Day Ensemble Chart: Here's the link to the daily charts: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml (click on the small chart there) ...and here’s the current chart which updates automatically each afternoon: Note for newbies: A neutral NAO index reflects the close to average state of the mean sea level pressure patterns or the “climatological” norm in the North Atlantic. This would equate to the anomalous high pressure in the south, particularly around the Azores and low pressure stretching from off the eastern USA seaboard in a wide band running north-eastwards to the east of Newfoundland, east of Greenland and through Iceland. A positive +NAO occurs when these patterns are stronger than usual (eg: the Azores high is more intense or more widespread and/or the Iceland low is deeper or more widespread than usual). A negative –NAO reflects a weak Azores high and/or less intense Icelandic low pressure. A strongly –NAO would reflect a reversal of the normal patterns with relatively low pressure in the Azores and high pressure further north towards Iceland. A “west based –NAO” (talked about recently) is when the pressure is higher than usual in the western Atlantic such as around the Newfoundland area). An “east based –NAO would indicate higher pressure than usual in our part of the Atlantic. This index produced by NOAA is based upon GFS model output and will fluctuate in line with that. Although ECM produce similar data based upon their own output this is not one of their “free-to-view” charts for public consumption. COMMENT (relating to the NAO chart above when it was showing January 29th data - it updates automatically each afternoon): The NAO is currently neutral but trending positive but never very strongly. Then most ensemble members trend less positive during week 2. This might suggest lower pressure in our vicinity but does not really show extensive deep LP over much of the Atlantic for week 2 (at this stage). MJO Ensemble charts: Here are today's MJO ensemble charts for the big 4 (all updated on January 29th) + Kyle MacRitchie’s modified chart (by request following recent discussions) with the live links below should you wish to check any future changes: UKMO (7 day forecast): ECM (14 day forecast): NCEP/GEFS (14 day forecast): JMA (9 day forecast): Kyle MacRitchie (30 day forecast): UKMO: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ukme.shtml ECM: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml GEFS: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml JMA: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/jman.shtml Kyle MacRitchie https://weatherandvines.com/?page_id=140 and his explanatory notes and further guidance: https://weatherandvines.com/?page_id=128 COMMENT (relating to charts on showing January 29th data - they update automatically each afternoon): The big 4 and Kyle MacRitchie all show slightly more positive signs with the models showing week 2 movements towards the key stages through to phases 7 and 8 with the GEFS and Kyle (with one of his ensemble members) ending in phase 1 at good amplitude. This “may” assist with some HLB later in week 2. Over to our experts for a deeper analysis. Northern Hemisphere Snow Cover: I show animations for snow cover and sea ice changes. These are produced by the National Ocean and Atmospheric Administration (NOAA). When you go to their site you can change the date range and go back over 10 years. You can change the speed and pause on any particular day. These are brilliant, very informative charts and great to play around with. I’ve have re-set the links below to show the last 2 weeks from January 14th to January 28th but you can change these again on the site: a) Animated Northern Hemisphere Snow Cover Changes (updated by NOAA January 28th): https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/nh/20170114-20170128 ....and here is their current chart: b) Animated Europe and Asia Day Snow Cover (updated by NOAA January 28th): https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/ea/20170114-20170128 ....and here is their current chart: BRIEF COMMENT: Much of eastern and south-eastern European is still snow covered. There continues to be well above average snow cover over northern Asia and this has expanded even further southwards and south-westwards. Scandinavia is fully snow covered, except the south (the high central plateaus usually have pretty complete snow cover for most of an average winter). The extensive snow cover over North America which declined sharply during the recent much milder conditions, has slightly increased again. Current Arctic Regional Surface Temperatures: GFS – Northern Hemisphere Current Temperatures for January 29th 1900 (12z – 1300 T+6): and here’s the link to live charts if you wish to view future changes (updated 4 times a day): http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=6&mode=1&carte=1 Here is my selection of Arctic Regional Temperatures: The the previous readings from my last full report are shown in brackets alongside North Pole: -20c to -28c (around -28c). Baring Sea/High Arctic: -8c to -16c (-12c to -20c). Scandinavia: south mostly -4c (+4 to -12c); north mostly -4c (-12c to -16c). Northern Siberia: -24c to -40c (little change). North West Russia: -12c to -24c (-8c to -20c) North-east Europe: -8c to -12c (0c to -8c). Greenland: -20c to -40c (-20c to -36c) Canadian Arctic: -16c to -32c (-12c to -32c). Alaska: -8c to -16c (-12c to -36c). Please note: For land masses I have tried to focus on readings away from the coasts and away from any mountainous areas. You can follow the trends by looking at the latest data at any time from now on. It is vital to note the time of day to take account of daytime/night time variations. So for like for like comparisons, for example the 1900 charts for each day should be available to view from the 12z (T+6) updates which are published around 1600 to 1700 or about 4 to 5 hours later. Svalbard Daily “Maximum” Temperature Forecast for 10 Days: Here are the links to the 3 Svalbard stations that I am monitoring together with a summary of D1, D5 and D9 values: Central/West Svalbard – Longyearbyen 28 m asl: http://www.yr.no/place/Norway/Svalbard/Longyearbyen/forecast.pdf January 30th -17c; February 3rd -6c; February 7th -2c. North-West Svalbard – Ny-Alesund: http://www.yr.no/place/Norway/Svalbard/Ny-Ålesund/forecast.pdf January 30th -21c; February 3rd -6c; February 7th -3c. Central South Svalbard – Sveagruva: http://www.yr.no/place/Norway/Svalbard/Sveagruva/forecast.pdf January 30th -22c; February 3rd -8c; February 7th -4c. Please note that the links above will update automatically at frequent intervals throughout the day. They are the Norway met office’s predictions. We need to be aware that these are only a forecast that is subject to change and I am told that the Arctic surface temperature forecasts are not completely reliable even at quite short range. BRIEF COMMENT: Temperatures have been much lower during the last week (even below the 30 year means) but as we move into February they will rise closer to freezing for a few days (at least) with southerly winds encroaching. To put the above figures into context, here is a link to the main Longyearbyen site: http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html This shows monthly means and actual highest/lowest temperatures recorded during this winter and goes back further. Svalbard has been seeing “maximum” temperatures often running at 8c to 10c above their long term average throughout most of 2016. This has been the pattern for several years and is reflective of the warming Arctic and record low sea ice cover. Final Comment: There is still plenty to interest us all as we move into the final third of winter Next Update: My next full weekly report should be on Sunday evening, February 5th.
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    This is an unusual set up for the UK, hence the model variations. The bigger picture according to seriously knowledgeable people like @Tamara tends to suggest that the hemispheric factors that actually drive our weather are in our favour for upcoming 'winter weather' and I for one would trust this rather than six hourly computer predictions that will inevitably try to revert to the climatalogical norm. There are some great members like @Steve Murr, @nick sussex on here that aim to give us viable options as to what may happen based on each run but unfortunately there are others that just wish to hear their own voice and take pleasure in finding opportunities to disappoint the majority. It is going to get cold, it might snow, its still winter, enjoy!
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    Good analysis and perspective earlier from nick s about the Scandinavian High and energy equation involved in any retrogression signal I think at this stage there are a few things to state (and in some cases re-emphasise) 1) There is a two day lag updating-work-in-progress continuing with the Global Synoptic Dynamical mode (GSDM) which provide us with a highly useful and NWP-pro-active guidance tool to asses how much tropical (MJO) and extra tropical (frictional and mountain torques) will produce a combined amplification wind-flow signal to impact the tropospheric NWP patterns and also poleward propagating mechanisms to further destabilise the polar vortex. The timelines involved in this means that the full effects of the tropical signal in the Pacific will be working their way polewards from tropics to mid and higher latitudes over a period of some days at a time. The signals can be evaluated in advance as to their likely impact on NWP - but full impact assessment is very a much a case of documenting progress daily through AAM total budgets as reflected by the Global Wind Oscillation. In this sense the MJO forecasts are not the whole story - it is the GWO that supplies the full wind signal and determine the hemispheric pattern and degree of meridionality of the jet stream We must therefore, very importantly factor this in when assessing NWP - and one highly good reason amongst others to avoid knee jerk responses to operational (especially) but also some ensemble date suites. This applies tonight as much as the last 10 days which (as far as I am concerned) is when this journey towards a cold spell began amidst suggested long term cyclogenesis. This rationale will also continue to apply, reflecting a highly dynamic evolution with a complexity of timings that imply whatever individual operational roll-outs *might* show, it *should* still be an exciting one too. 2) Next up, the GSDM aspect has to be considered in tandem with stratospheric developments and the movements of the vortex within the polar field. The GSDM is contributory to this in terms of poleward rossby wave eddies in evidence set to further perturb the vortex, but the maximum damage potential in the form of cold air advection through strong amplification is made possible by the most 'favourable' destabilisation mode within the vortex itself. There is increasing agreement for the vortex to become resident over Siberia, but there is not (yet) agreement on whether this arises through split or displacement. Clearly displacement mode involves momentum transport across the pole and, as nick rightly says, this process comes with greater energy (temporarily) exerted on the Scandinavian block. One more reason to not be surprised by the NWP volatility and differences evident between models and intra day modelling suites. Clearly current NWP highlights these energy imbalances - but it is vital that they are captured merely as snapshots in time and neither represent the inevitable, nor are they, as already stressed, a complete picture by any means With that in mind, lets look at what we know, which includes todays GSDM updates (remember the two day lag) As suggested in yesterdays post update, global atmospheric angular momentum tendency was set to respond sharply. Todays lag to the 4th shows it has rocketed upwards in continued response to the upstream tropical (MJO) signal coming into the Pacific - destined eastwards But as stated already, the tropical 'engine catalyst' for the amplification signal isn't the complete story. Feedback processes for poleward propagation of amplifying poleward eddies from the tropics to extra tropical mid and higher latitudes occurs over timeline periods. NWP is constantly calculating this evolving process and adjusting. When it involves complex amplification and strong blocking processes such as we currently experience - expect uncertainty and drop in performance - but don't be sad and fitful over less palatable solutions which may be either transitory graemlins or phantom model weather watching demons The Global Wind Oscillation (two day lag once more) has continued etching up in amplitude through Phase 4 (again as suggested yesterday) as it starts to respond to the rapid rise in angular momentum tendency. This has implications for global torques moving forward, and the net outcome of amplification in the atmospheric circulation budget will determine the tropospheric response available for cold air advection moving ahead. That is also beyond the easterly. The movements within the polar field will clearly either offset or augment this potential depending on displacement or split mechanisms - but make no mistake, a harmonious tropical and extra tropical wind-flow signal cuing up large amplification forcing dovetailing with favourable stratospheric developments could deliver an icing to top the initial Scandinavian cake. Don't fret over any suggested pause heading into next week. We cannot yet know all the answers. We can only look around corners available. But the GSDM offers an additional forward insight to where NWP may head. Atmospheric circulation and stratospheric caveats aside, this has a long way to go yet and the nice little easterly could conceivably be a precursor to a bigger reload from the arctic to round off official winter 2017. Edit: To latest ECM ensemble tweet 'scare'. Yet another snapshot in time which tells a half complete story and doesn't factor in total evolution longer term of pattern which NWP is yet to assimilate. Only yesterday/this morning we heard long term METO prognosis was a cold February...
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    Evening All - So another day at the office & finally we are now seeing some indications that the very dry boring Easterly might not be a very dry boring Easterly... Modelling today has seen better agreement in the flow becoming ENE across the week courtesy of a developing area of lower heights somewhere close to the E or SE - This will enhance the instability for the E & SE but also support the push west of the cold uppers- creating more in the way of snow flurries- Its pretty easy to suggest the areas prone to seeing snow - however if I was pressed to pinpoint the region most at risk from 'disruption' It would be Lincs up to tyne & wear - however the models especially the euros that the risk moves further towards the SE fri / sat & early sun... The rest of the country is dependent on how much the Easterly onshore flow can project those showers across & again Friday > Saturday looks best with low maxima & solid frosts- Detail is a bit sketchy but an area of snow could cross southern areas Sunday - which also may herald milder air from the SE- Post 144 the models have 'edged' towards the ever progressive ECM - with the wedge of high pressure from the atlantic following a rainbow shaped journey from the azores via Iceland then on down to scandi - encouraging low heights over spain to lift up Northwards- however this by no means a done deal as its theory is based on model assumptions in areas where they have been totally wrong in the last few days * The path could be interupted by a shortwave in 'any' location- * The SE flow at 144 > 168 could still sharpen up to Easterly - why? The modelling of the Iberian low has been to deep & on the flip side of that the modelling of any italian heights has been to shallow- so the seesaw could swing towards a flatter flow.. like this http://www.meteociel.fr/modeles/gefs_cartes.php?code=1&ech=6&carte=1&mode=0 * The high pressure may stretch/shear east & west rather than just 1 blob-... which leads onto the final point.. The greenland high... In the timeline about 216-240 we see 'potential' for a sharp rise in pressure over Greenland, remember after research the Greenland high really only develops from 2 regions * azores high ridging North * Scandi high angled NW or both- ( Nov 2010 was both ) Ive picked a chart from todays 12z - Note the allignment of the flow is from SE to NW - you have all that energy essentially reversed against the jet & what happens is the jet gets smashed upwards over Greenland - hence greenland high... So, in summary tonight- cold from Weds, poss snow in the NE along the stalled front before it fizzles... flurries Thurs in the SE/E& NE- with everything pushing further inland Fri / Sat- .... poss band of snow over the SE > then south / midlands / SW on sun... Some accumulations possible... S
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    WINTER 2016/17 FULL REPORT No. 14 WITH FEBRUARY 19th INPUT Outlook: From Warm To Cold To Mild This Week – Then What? There Are Some More Encouraging Signs For Coldies Into Early March My last full report was on page 21 of this thread. Apart from my routine features in this report, I shall include a special focus on the warm interlude predicted for early this week and put it into context Brief Review Of The Last Week and the Current Position: Last Sunday, after a little more snow in places the short cold spell was already losing its grip with milder air pushing up from France. The Scandinavian high pressure (HP) sunk steadily southwards and now lies over southern and central Europe in a broad band stretching to the east and ridging westwards linking up to an extension of the Azores HP. Temperatures generally recovered to nearer normal, slightly above on some days but with slight frosts on several nights and some fog patches. There were a few short periods of mostly very light rain moving from south-west to north-east. The European cold block has weakened considerably and has been steadily eroded by westerly winds. The deeper cold has been pushed back into western Asia and Russia. Northern Scandinavia is temporarily colder again with a northerly incursion up there. Daytime temperatures have risen above freezing even in much of central Europe but night frosts have continued away from the far west of Europe. This can be seen on the European surface temperature charts below (0650 close to minima and 1250 close to maxima): CURRENT “LIVE” TEMPS FEB 19TH FEB 19TH 0650 TEMPS FEB 18TH 1250 TEMPS For the next few days we can look to our west and south-west for our upcoming weather. The Short Term Position and the Warm Interlude: The HP to our south-west is bringing in a tropical maritime flow originating from between the west of North Africa and the Azores. This will flood across the country during Sunday night and into Monday. Temperatures will rise well above normal and reach unseasonably high values in the south. A wide area of central southern, the south-east, East Anglia and the Midlands will see temperatures approaching or exceeding 15c on Monday. The air stream will be very moist with some low cloud and hill fog and more generally cloudy. Any areas which see the sun break through may see temperatures several degrees higher but perhaps, not quite as extreme as forecasts suggested several days ago. Favoured spots might be to the lea side (north-east) of any slightly higher ground such as towards the north Kent coast and around Gravesend. A wider area from north London through Hertfordshire into south Cambridgeshire might also see the highest values tomorrow afternoon. It may be hit or miss for maximums up to 17c (possibly even a degree higher). The Arome 0z chart below is a typical representation and gives a very rough idea of the maximum temperature distribution over southern England for the 12 hours up to 1900 tomorrow. AROME 0z T+42 MAX TEMPS There has been the usual misreporting in the press and several rather inaccurate comments on this forum in the last few days. The Daily Mail said that temperatures would reach 18c and the highest for over 160 years. They may be right about the temperature but not the record. This value has been exceeded on at least 8 occasions in those 160 years and 19c has been exceeded on 3 occasions. The long standing record “was” on 27th February 1891 with 19.4c in Cambridge but that was exceeded during a memorable warm spell from 7th to 15th February 1998. Temperatures rose above 15c on 8 consecutive days somewhere in the UK. On February 13th the maximum exceeded 19c at a number of locations in southern England and the Midlands. The new February record was broken with 19.7c at Greenwich, 19.6c in Worcestershire and 19.5c in Somerset. This spell was all the more remarkable for being in the first half of February as well as for its longevity. 1997-98 was the time of the “super El Nino” – the strongest on record (almost matched in 2015-16). More tentative early records suggest that 1891 was also a strong El Nino year (Wikipedia with links and “confirmation required” entry; NOAA’s records only go back to 1896). Interestingly both the 1891 and 1998 warm spells were followed by a very cold spell in early March. There was no SSW or any warming events in 1997-98 and records do not go back to the 1890s. It may not be too long before we see 21c (70f) exceeded in February if the current warming continues (although the trend “may” be reversed during the next 30 or so “Maunder Minimum” years but that’s another discussion). There was another noteworthy and remarkable warm spell in early March 1948. That saw 23.9c at Wealdstone, Middlesex (near Harrow in NW London) and even 23.3c at Cromer (on the north Norfolk coast). Higher temperatures have all occurred towards the end of March (25c reached in 1929, 1965 and 1968) but nothing comparable in the first half of March. All these events involved tropical maritime incursions and HP very close to our south-west, south or south-east and followed quite prolonged dry spells. Very high values in December and January are usually confined to the fohn effect with adiabatic winds on the lea side of mountains such as at Rhyl in North Wales downwind from Snowdonia. By mid-February the sun can just have enough strength to burn off the low cloud and warm the surface slightly. In the charts below, I compare the current pattern to the two previous February events and the March event from the archives: GFS 6z T+30 Mon 1300 NCEP 13.2.1998 NCEP 27.2.1891 NCEP 9.3.1948 Later This Week and Through to Next Weekend: At the time of writing (1100 Sunday) the tropical air mass sourced from the far south is predicted to be cut off during Tuesday with the HP slipping further south and LP to the north becoming more dominant and introducing more of a westerly flow. If it had persisted for a couple more days we may have seen the 13th February 1998 record being challenged. It looks like we are set to enter a much more changeable period with a succession of LPs running mostly to the north of Scotland. Some of the models “had” been showing a brief Arctic incursion for around Friday into Saturday and even a little snow but this has mostly been watered down into an even briefer period. So, perhaps less than 24 hours with either a polar maritime or Arctic maritime sourced flow, an Azores ridge and another LP to follow. The period from D3 to D5 can be summed up as some quite short periods of rain, heaviest in the north, moving through quite quickly in the brisk and at times quite strong winds with drier, clearer or brighter interludes in between. It will be mostly rather mild but far less so than tomorrow with shorter colder incursions perhaps with a frost if they occur overnight. Any snow looks like it will be confined to showers over northern hills and mountains during the colder interludes. Of course the minor details might change so let’s take a look at the position for next Friday with one of my cross-model checks. Northern Hemisphere Pressure for Friday, February 24th at 0100 (with adjusted times to provide an accurate comparison): GFS 6z T+114 ECM 0z T+120 UKMO 0z T+120 GEM 0z T+120 NAVGEM 0z T+120 JMA 12z Feb 18th T+132 GEFS ens mean 6z T+114 Met O Fax 12z T+120 for 1200 Thur Feb 23rd (latest available) The main variations are the strength, timing and exact track of the LPs and the extent of the Arctic incursion. The broader pattern is generally agreed by the models but the finer detail is still somewhat uncertain. Into Week 2 and Beyond: The unsettled spell looks like continuing for much of this period too. There still seems to be some debate on the likelihood and timing of the final warming event. Going by the recent posts and comments on the strat thread it seems possible or perhaps probable that we might be looking at some changes impacting around the second week in March. There are hints of some HLB being picked up in distant FI with the GFS showing a possible Svalbard HP or Scandi HP by around T360 to T384 (D15-D16). That’s a long way off but a much colder spell before mid-March cannot be discounted. I will pick up on northern hemisphere and Arctic temperatures later in this report where there are some much more encouraging signs. In the meantime, let’s have a look at the Jet Stream. Northern Hemisphere Jet Stream – Current Position: GFS 6z T+6 The Jet Stream is going through a transition but continues to be split from North America through the Atlantic and into southern and central Asia. The lower arm takes a very southerly track through North Africa, still well south of Europe and through the Middle East into south-west Asia. The northern arm has strengthened during the last week and is particularly strong in the Pacific (where the two arms rejoin and this is producing the unusually heavy rainfall that is relieving the two year drought in California). It’s still slightly meandering and fragmented in the Atlantic where it moves north-eastwards and approaches the UK from the north-west. Northern Hemisphere Jet Stream for Sat 18th Feb – 0100 (with adjusted times to provide an accurate comparison): GFS 0z T+138 NAVGEM 6z +138 GEFS ens mean 12z T+132 (updates?) JMA 12z Feb 11th T+156 Moving on to D6, let’s have a look at several cross model Jet Stream charts (above). All the models show the northern arm taking charge and firing through North America and right through the UK. The JMA shows it rather stronger than the other models, the NAVGEM the weakest with the GFS and GEFS ens mean in between but still showing a rather meandering path across the Atlantic. The southern arm continues on a similar very far south track but is weakening across the Atlantic. As it moves out of Asia it moves northwards in the western pacific to become the main arm where it’s at its strongest. There is a break away loop circling Alaska. At no stage is the Jet Stream at all strong through eastern Europe and into Russia and western Asia – so the cold block will not be broken up completely, which may be important much later on. Looking at the extended charts (not shown as they are too far out) there are already signs of the Jet Stream starting to weaken again, particularly in the Atlantic where the main arm starts to dive well south of the UK again. This would be in line with possible HLB towards the second week in March and another sign to keep an eye on in a week or so. Northern Hemisphere Current 2m Surface Temperatures and 850s: GEFS ens mean 6z T+0 GEFS ens mean 6z T+0 Northern Hemisphere 2m Surface Temperatures and 850s for Sat Feb 25th – 0700: GEFS ens mean 6z T+144 GEFS ens mean 6z T+144 Another useful indicator for assessing the likely future strength of the Jet Stream in the Atlantic is the thermal contrast between the eastern USA and the adjacent ocean. Right now much of the USA has resumed its unusually mild period following a brief cold snap in the north-eastern states with considerable snowfall. Most of the cold remains entrenched further north over much of Canada. By next weekend, the colder air has seeped southwards over the western USA but the eastern states are particularly mild, if not warm. So, based on these charts, there will be little assistance from the thermal contrasts to fire up the Jet Stream any further, quite the reverse in fact. Note also, the build-up of deep cold in the Arctic which I will return to later in this report. Another sign that we might yet see our coldest weather of the winter in early Spring! London 2m Temperature Ensembles 0z February 19th to 6th March: COMMENTS (in respect of the Feb 19th chart - it updates automatically): This very useful ensemble chart highlights the current (Sunday 0z) differences in the model output. It and similar charts for other locations are often posted on this thread but I like a little more analysis. Both the NCEP and ECM start off showing tomorrow’s warm day, then the cooling off around Friday into Saturday (more especially the ECM) followed by a return to milder conditions but nowhere near as mild as tomorrow will be. Predicted temperatures are only slightly above average towards month end. Then the NCEP (op run goes at the mildest end well above the average indicated and only falling back on D15. The ensemble means show an increasing number of much cold outcomes during the first week of March. This takes us right up to the suggested period for the start of the cold spell (if it happens). The next week will be a really fascinating one to watch for developments. Note that the ensemble charts shown by the likes of Knocker will not show these “possible” changes for a while. The 10-15 days means may start to towards the end of this week and more so by early next week. Now on to my routine coverage. Arctic Sea Ice News and Analysis: The last full monthly report was published last week on February 7th. This is a fascinating but quite distressing read. Please note that the current ice extent map and the comparison chart to the mean are updated daily and are always of interest. Here’s the link for the latest report and updates: http://nsidc.org/arcticseaicenews/ This chart shows the current extent of the sea ice (as on February 18th) in relation to the 30 year means. Source: National Snow and Ice Data Center (NSIDC) COMMENT: (relating to the chart above when it was showing February 18th data - it updates automatically each afternoon): The “rate of recovery” during December was very close to a record but this was insufficient to avoid the overall extent still being at record lows. Since then, the position became steadily worse. There was a continued recovery (with several pauses) during January but sea ice growth had almost stalled and even receded slightly at a time when the Arctic is historically at its coldest. Fortunately, much stronger further growth has commenced during the last week. The overall ice extent remains well below the previous record low set during the 2012-13 Winter. Now, we learn that sea ice extent in Antarctica (late summer there) is also at record lows. Overall, the world’s sea ice is well below previous record lows. This rapidly accelerating loss is extremely worrying and will have all sorts of adverse impacts on the world’s weather patterns. It may well go some way to explaining why we struggle to get any prolonged cold spells into our neck of the woods. This is an extremely complex subject which many experts are finding difficult to explain. Despite the background of global warming, let’s hope that the recent trend of greatly accelerated ice loss proves to be a temporary pattern. Arctic Current Sea Surface Temperatures (SSTs): NOAA SSTs Feb 18th NOAA SST Anomalies Feb 18th COMMENT: Although the Arctic surface temperatures have fallen sharply during the last week (see later) and overall ice extent has been rising again, the two charts above go a long way to explain why there has been such a struggle for sea ice to grow in the Barents and Kara Seas on our side of the Arctic. The SSTs need to be below the -1.5c threshold (the purple colour). Sea water will start to freeze when it is below -2c but that is for normal salinity. There is slightly lower salt content in the Arctic (due to ice melt) and the threshold is nearer to -1.5c. There are some areas with SSTs well above freezing and the current anomalies are widely 4c to 6c above average and up to 8c above in places. These higher SSTs are a legacy of the 2015-16 winter when the Atlantic Jet Stream powered well into the Arctic for much of the first half of winter. This shifted much warmer than average currents right up to the edge of the ice sheet. This anomaly is exceptional and comes on top of the already generally warming Arctic. It will be interesting to see how much ice growth can be achieved during the next few weeks with much colder surface conditions likely to persist. Unless the SSTs reduce substantially, the anomalies might be carried through the summer and into a third winter. I shall include a brief update on these in my future reports. Arctic Oscillation (AO) 14 Day Ensemble Chart: Here's the link to the daily charts: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml ...and here’s the current chart which updates automatically each afternoon: Note for newbies: The AO index reflects the amount of HLB in the Arctic. A positive +AO reflects very little HLB and a strongly +AO reflects no HLB anywhere in the Arctic. A negative –AO reflects some HLB and a strongly –AO reflects substantial HLB with more intense high pressure and/or more extensive HLB in various parts of the Arctic. This index produced by NOAA is based upon GFS model output and will fluctuate in line with that. Although ECM produce similar data based upon their own output this is not one of their “free-to-view” charts for public consumption. COMMENT (relating to the AO chart above when it was showing February 19th data - it updates automatically each afternoon): The Arctic Oscillation perfectly reflects the current GFS model output. It start off positive, briefly dips towards neutral later this week (the very brief colder snap), then goes strongly positive for about a week before all the ensemble members start to trend sharply lower later in week 2 with some going negative towards the end in early March – showing signs of greater HLB then. North Atlantic Oscillation (NAO) 14 Day Ensemble Chart: Here's the link to the daily charts: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml (click on the small chart there) ...and here’s the current chart which updates automatically each afternoon: Note for newbies: A neutral NAO index reflects the close to average state of the mean sea level pressure patterns or the “climatological” norm in the North Atlantic. This would equate to the anomalous high pressure in the south, particularly around the Azores and low pressure stretching from off the eastern USA seaboard in a wide band running north-eastwards to the east of Newfoundland, east of Greenland and through Iceland. A positive +NAO occurs when these patterns are stronger than usual (eg: the Azores high is more intense or more widespread and/or the Iceland low is deeper or more widespread than usual). A negative –NAO reflects a weak Azores high and/or less intense Icelandic low pressure. A strongly –NAO would reflect a reversal of the normal patterns with relatively low pressure in the Azores and high pressure further north towards Iceland. A “west based –NAO” (talked about recently) is when the pressure is higher than usual in the western Atlantic such as around the Newfoundland area). An “east based –NAO would indicate higher pressure than usual in our part of the Atlantic. This index produced by NOAA is based upon GFS model output and will fluctuate in line with that. Although ECM produce similar data based upon their own output this is not one of their “free-to-view” charts for public consumption. COMMENT (relating to the NAO chart above when it was showing February 19th data - it updates automatically each afternoon): The NAO is slightly positive for most of the 2 week period but trending towards neutral later on with signs of it heading into negative territory after that. This broadly reflects fairly close to average pressure distributions in much of the north Atlantic with fairly low pressure to our north and west and the Azores HP to our south-west MJO Ensemble charts: Here are today's MJO ensemble charts for the big 4 (all updated on February 19th) + Kyle MacRitchie’s modified chart (by request following recent discussions) with the live links below should you wish to check any future changes: UKMO (7 day forecast): ECM (14 day forecast): NCEP/GEFS (14 day forecast): JMA (9 day forecast): Kyle MacRitchie (30 day forecast): UKMO: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ukme.shtml ECM: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml GEFS: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml JMA: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/jman.shtml Kyle MacRitchie: https://weatherandvines.com/?page_id=140 and his explanatory notes and further guidance: https://weatherandvines.com/?page_id=128 COMMENT (relating to charts showing February 19th data - they update automatically each afternoon): After broader agreement in the last 2 weeks we see some divergence again now. The big 4 all start off with the MJO in phase 1 at decent amplitude. Then the UKMO moves slowly through phase 1 and ends up next weekend near the phase 2 boundary maintaining good amplitude. The ECM takes a similar route over the same period, then progresses through phase 2 and on into phase 3 by the end of week 2 and at slightly reducing amplitude with some ensemble members moving towards the COD (the Circle of Death) - could this mark a later return to the positive phases 7, 8 and 1 during mid-March or might it become inactive?. The GEFS takes a much more interesting route, holding for longer in phase 1 initially (perhaps in line with that very brief colder snap later this week) and then it heads erratically back towards the COD but very close to the phase 8 boundary (some members cross into phase 8 and stay there). Then later in week 2 there is a renewed sign of life with a move back out of the COD towards the phase 7 and 8 boundary with some members moving into phase 7 at low amplitude. This is the longest forecast period of the big 4 and might be supportive of a move towards greater HLB by the second week of March. Early signs but one to watch very closely. The JMA has simply fallen in love with phase 1 and hangs around there for the entire period at decent amplitude! Kyle MacRitchie (with his adjusted model for ENSO and other tropical signals) is rather different. He starts off in phase 7, progressing through phase 8 during this week, then on though phase 1 next week reaching phase 2 around March 4th – all at good amplitude. Then all the members progress through phase 2, 3 and 4 by mid-March at slightly decreasing amplitude. Finally, they move into phase 5 bordering the COD by March 21st. Overall, a rather mixed picture but possibly some encouraging signs for later on. As @Tamara and several other highly respected experts keep telling us, we cannot simply look at the MJO in isolation. It must be viewed in line with the other teleconnection signals which play an increasingly important role in helping us to understand and forecast forthcoming broader pattern changes. I do hope that even those who criticise these experts (extremely unfairly and without any factual basis whatsoever in my view – usually but not always through a lack of knowledge of the subject) realise that they have consistently done a far better job this winter than most of the longer term model output has managed. Tamara never got very excited about the December blocking (which turned out to be almost entirely MLB). She predicted that the January Arctic plunge would be a brief one. She then started to gain more interest herself as the stratospheric warming events took place but she warned us that the main cold (if it comes) will be delayed until either late February or early March. Sure enough, we had that 5 day recent easterly spell but that was too early and the promising Scandi HP sunk away southwards (much to my own disappointment, as I was championing the strength of the cold block, as well as for many others). So still the final hurdle to cross in terms of the possible (or even probable) upcoming cold spell but so far Tamara has been almost spot on. I have an increasing belief in the teleconnections science and will do my best to improve my understanding of it all. Who knows, I might even be able to make greater use of them in these reports in due course! Northern Hemisphere Snow Cover: I show animations for snow cover and sea ice changes. These are produced by the National Ocean and Atmospheric Administration (NOAA). When you go to their site you can change the date range and go back over 10 years. You can change the speed and pause on any particular day. These are brilliant, very informative charts and great to play around with. I’ve have re-set the links below to show the last 2 weeks from February 4th to February 18th but you can change these again on the site: a) Animated Northern Hemisphere Snow Cover Changes (updated by NOAA February 18th): https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/nh/20170204-20170218 ....and here is their current chart: b) Animated Europe and Asia Day Snow Cover (updated by NOAA February 18th): https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/ea/20170204-20170218 ....and here is their current chart: COMMENT: Little overall change during the last week. Part of central and much of eastern and south-eastern European is still snow covered (slightly receding in recent days). There continues to be well above average snow cover over northern, west and central Asia but a slight decline further south-east. Scandinavia remains fully snow covered, except the south of Sweden (the high central plateaus usually have pretty complete snow cover for most of an average winter). The extensive snow cover over North America has declined again during the last few days (the north-eastern states had quite a dumping a week ago). The extensive snow cover over west Asia, Russia, eastern Europe and Scandinavia may well become very important if we are to see the right synoptics for a final attempt at another cold spell. Finally, in the animated chart, you can clearly see the ice build-up towards Svalbard during the last few days. Yet another highly encouraging sign. Current Arctic Regional Surface Temperatures: GFS mean– Northern Hemisphere Current Temperatures for February 19th 1900 (6z – T+12): and here’s the link to live charts if you wish to view future changes (updated 4 times a day): http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=6&mode=1&carte=1 Here is my selection of Arctic Regional Temperatures: The previous readings from my last full report are shown in brackets alongside North Pole: -28c (-20c to -28c). Barents and Kara Seas: -8c to -20c (-4c to -20c). Scandinavia: south +4c to 0c (-4c to -8c; north 0c to -16c (0c to -8c). Northern Siberia: -28c to -40c (-20c to -40c). North West Russia: -12c to -24c (-4c to -8c) North-east Europe: +4c to 0c (-4c to -8c). Greenland: -20c to -40c (-16c to -32c) Canadian Arctic: -20c to -36c (little change). Alaska: -20c to -36c (-12c to -40c). Please note: For land masses I have tried to focus on readings away from the coasts and away from any mountainous areas. You can follow the trends by looking at the latest data at any time from now on. It is vital to note the time of day to take account of daytime/night time variations. So for like for like comparisons, for example the 1900 charts for each day should be available to view from the 12z (T+6) updates which are published around 1600 to 1700 or about 4 to 5 hours later. COMMENT: Much of the Arctic, including the North Pole and Greenland as well as northern Siberia and parts of Russia have seen deepening cold. It looks like this trend will continue for at least the next week leading to the lowest values for the whole of this Winter. This would be very timely (for coldies) if we can manage the right synoptics in early March. Svalbard Daily “Maximum” Temperature Forecast for 10 Days: Here are the links to the 3 Svalbard stations that I am monitoring together with a summary of D1, D5 and D9 values: Central/West Svalbard – Longyearbyen 28 m asl: http://www.yr.no/place/Norway/Svalbard/Longyearbyen/forecast.pdf February 20th -12c; February 24th -13 c; February 28th -10c. North-West Svalbard – Ny-Alesund: http://www.yr.no/place/Norway/Svalbard/Ny-Ålesund/forecast.pdf February 20th -14c; February 24th -19c; February 28th -12c. Central South Svalbard – Sveagruva: http://www.yr.no/place/Norway/Svalbard/Sveagruva/forecast.pdf February 20th -12 c; February 24th -18c; February 28th -14c. Please note that the links above will update automatically at frequent intervals throughout the day. They are the Norway met office’s predictions. We need to be aware that these are only a forecast that is subject to change and I am told that the Arctic surface temperature forecasts are not completely reliable even at quite short range. COMMENT: Temperatures had risen just above freezing for 10 days from late January into early February with the warmest period of the winter. Since then, temperatures have fallen back sharply and have been close to their 30 year means for the last 10 days and look set to continue near this level for the remainder of February and into March. This is excellent news on several counts. The recent recovery in the sea ice extent should continue at a far better rate. The SSTs should start to fall back and begin to reduce the exceptionally strong anomaly. Finally, for coldies, if we are to see some HLB with an Arctic air stream at some stage, the source of surface cold should be considerably lower than it has been at any time this winter (and for several past winters). This is the best news that I have been able to report on since I started monitoring these Arctic temperatures for my reports from January 2016. I did study Arctic temperatures for many years before I ever joined the NetWeather forum and I hope that the dreadful recent news on the declining sea ice will at least temporarily be ameliorated. To put the above figures into context, here is a link to the main Longyearbyen site: http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html This shows monthly means and actual highest/lowest temperatures recorded during this winter and goes back further. Svalbard has been seeing “maximum” temperatures often running at 8c to 10c above their long term average throughout most of 2016. This has been the pattern for several years and is reflective of the warming Arctic and record low sea ice cover. FINAL COMMENT: This winter may be far from over. In early March it is highly likely that we shall see the deepest cold of the winter season in the Arctic and also some more deep cold re-establishing itself in western Asia (where it has never really subsided since late October) and in north-west Russia. So, this is the deal for coldies – I shall lay on the cold to our north and east to tap into and our strat experts need to ensure that the final warming event at last creates the right synoptics to deliver it to the UK. A further deal to those that like a Spring warm up – allow us die hard coldies a decent cold and snowy spell first half to March, then we can all think of Spring. As I said last week, it’s all a mind set and we cannot control the weather – so just accept it. Proper Spring doesn’t start until March 21st and mother nature will catch up later on. I look forward to producing an even more encouraging report next Sunday. NEXT UPDATE: My next full weekly report should be on Sunday evening, February 26th.
  23. 47 likes
    Come on folks lets turn a page on some of the earlier gloom. Theres more things in our favour in terms of cold and snow than at anytime for the whole winter. I can understand people might get a bit worried seeing the Scandi high flatten for a time but its important to think of that as the next chance to get some deeper cold into the circulation. The outputs are likely to get a bit messy for a time as they try to pull a lobe of high pressure to the nw. As this happens you want to see lower heights develop to the east that will mean some colder air is getting injected into the circulation. Normally I'm not that optimistic about things and it takes a lot for me to chill out and not moan so my lack of moaning I hope gives cause for some optimism!
  24. 47 likes
    It's to do with how many planetary waves are affecting the vortex at any one time. If there is only one wave affecting the vortex then we call that wavenumber 1 and this will displace the vortex. Imagine a balloon blown up - if you put 1 finger of pressure on that balloon then you will distort it into a more banana like shape - akin to a wave 1. For wave 2, put 2 fingers of pressure on the balloon on opposite sides and you will achieve an '8' shape - with a split down the middle. So that is what we are seeing with the strat vortex - here is the classic wave 1 displacement And late in the run we see the pinching effects that wave 2 brings Technically, the waves don't need to be geographically based, but in reality they tend to be Atlantic or Pacific based because of the position of land masses and mountain ranges. Charts courtesy of weatherbell
  25. 46 likes
    As usual there are different ways of looking at this. A few things: 1) We have been able to successfully trace the end of one cold snap in mid January to plot (in advance) the development of the next (albeit its not the 1991 redux one might hope for). That has been possible, through some collective effort and different methodologies converging. As a practical community exercise that illustrates one of the benefits of being a member of a forum such as this - and far too often it gets obscured and not acknowledged as much as it should. The rollercoaster element might provide the excitement when things look good, but it also can serve to detract the community positives when the solutions on offer do not appeal to the eye of the audience 2) Participating in the regional thread over the coming days will make the most of the snow opportunities there are to come, so it need not be a let down at all. We cannot make it snow. let alone everywhere, and not to desired quantities, but its still possible to make the most of what might come. Otherwise all the chasing since mid January (for those who managed to see snow) has no reward away from the computer. So best head out take pics and enjoy it while it is here and then report back 3) GP has posted in the technical thread and it makes complete sense as reflected by NWP. I spoke the other day about the need for the tropical signal (the nucleus for downstream amplification) to work its way through to the extra tropics and only then the full amplification potential downstream can be assessed. Clearly from the downstream pattern that has come into model consensus today, the amplification potential suggested by the Pacific forcing is not apparent to that extent and I had been thinking yesterday evening there must be (again!) a destructive I/O signal not allowing it to fulfil expectations. In data terms it doesn't seem much at all, but in terms of ripples in a pond stemming from the smallest pebbles, they nevertheless spread far and wide. The timelines I have referred to are clearly set to be at the longest end of the envelope, but then estimations can only be as good as the last data set. This certainly doesn't debunk the initial thinking, but it does mean we will not get the more seamless movement from one cold evolution (Scandi High) to the next that seemed possible - and it explains why the retrogression signal (which had been responding to in line with expectations) has faded. If anyone thinks it should be due, I will accept any responsibility for heightening any expectations by speaking of converging signals producing "the icing on the cake" but then I will also stick to the fact that this had been quite feasibly reasoned (and believe the fullness of time will show that) 4) The interpretation to take from all this in GSDM terms suggests that the Global Wind Oscillation orbit will be much shallower amplitude than anticipated until the destructive interference from the tropics diminishes. I find it very frustrating that such a compelling tropical and extra tropical amplification signal has been diluted and delayed - having coming so far so well. Hand in hand with a split vortex solution rather than a displacement, some of those highly appealing ensemble solutions up to yesterday would not have stayed in the virtual world.... 5) However there is still the compelling real time signal spoken of in detail previously of rapidly rising angular momentum tendency. The MJO signal might have had an unwanted intervention, but it has not gone away. Lagged by the tropical glitch, rising frictional torque and then mountain torque still cues up the expected amplification - but destined for a cold finale to winter and usher into Spring. Whether the whole audience welcomes that or not is completely subjective of course. 6) Finally, what we can deduce from all this is yet another proof exercise of what I often repeat. The teleconnections do work, but they do not always evolve to optimise the most desired result. But then that has always been the point - this forum has a natural bias, the science of meteorology has no bias.
  26. 46 likes
    Evening All so a rare call of the ECM to follow the GFS / UKMO blend has seemingly landed on the runway tonight with all 3 models on the same page evolution wise - Following on from last nights post - where I was trying to highlight the importance of the cycle 1 & 2 process & the possibility of the UK just being to far west for cycle 1 seems to have gained a little clarity today- Taking the big 3 into consideration sees cycle 1 leaving the UK upstream of an easterly 'waft' - think 1980s bisto advert... The UKMO 144 shows this very clearly with perhaps the residents of Lowestoft who have a cold persusion peering east out the window- watching & waiting- Even the best alligned GFS op doesnt quite get there - so T144 looks to cold but not deep cold... post that the 'big 3' all have cycle 2 undercutting - ive checked UKMO 168 its good to go- However ECMs shape is EPIC - so post 144 the old fashioned 'classic' southerly draw veering Easterly - spanning 2-3 days with dewpoints draining away.. well thats the plan anyway.... Also note the Cobra runs on the increase now in ECM ENS with Op & control in harmony- FWIW I think the longwave pattern is pretty reflective of what to expect- Scandi + Eastern Pacific High - then cycle 2 throwing a low amplitude atlantic ridge in the mix as well which angles the jet SE over the UK producing the trigger low- - key areas to watch for everyone over the next 24-72 hours which is mainly 2 clear things- * European flow allignment of the upper air cold pool- This is critical as the UK is at the end of the line with a cold pool span of about 700 miles North to south but an available target area of about 3-4 thousand miles- so changes in the angle of attack of that upper air pool has repercussions- in recent years the high has flattened slightly to quick & the cold pool has alligned more North -South heading towards Italy, or equally of the block has weaknesses on the SW flank then the cold pool moves west quickly before North west & North up through scandi curving away yet again from the UK so this chart- about T150 ish is crucial - we could do with this being alligned perfectly SW towards the UK, GFS isnt bad -we need to maintaing low heights across Southern & Eastern Europe to keep funnelling the cold west- * The other issue will be the trigger low, so many times in recent failures where instead of dropping SE into the near continent to support the final leg of the colds migration west- it actually heads NE & gets lodged in the SW portion of Scandi- This then blocks the retrogression of the high & it quickly sinks SE- so again GFS looks great- Notice the little kink dropping SE on cycle 2 So there you have it- all seems great tonight but it could all go titicus verticus over the next 24-48 hours- T144 is the key line tonight to see everything falling into place so not total FI but far enough to have to wait till friday... Eyes down for the pub run.... S
  27. 45 likes
    Last week ( & @bluearmy) will back me up I posted the ECM ENS suite which had just 1 member from 51 showing an easterly - I called it the cobra run - that has now verified... iI will be posting up some info this eve around 1030 that should make some interesting viewing.... S
  28. 44 likes
    WHY THE ECM 12z IS "NOT" MILD! There has been quite a lot of nonsense spouted on the thread today and I have found some of it quite exasperating. I am about to prove why the ECM 12z run is not a mild one. I do not want to sound like I am preaching but I feel that a few basic lessons in understanding the charts is required. Several of the 12z models such as the GFS and ECM have shown the Scandinavian HP sinking south-eastwards from around D6 to D8 introducing more of a slack south-south-easterly flow for several days. Yes, this does temporarily cut off the direct supply of the deep cold from the north-east and the 850s do mix out and warm up to some extent but that's about it. I have tried to explain for several weeks now how surface cold will become entrenched and that much of Europe is likely to have at least some snow cover by early next week. Let's accept for now that the ECM evolution is accurate, although I find part of it rather questionable. I have heard several comments that the air is going to come from North Africa! Just because the flow appears to come from a south-south-easterly direction does not mean that this is the wind or temperature source. A basic principle is to understand the coriolis force. In simple weather terms we see winds blowing towards a LP system and away from a HP system at the surface. The winds do not blow parallel to the isobars but they are "backed" across them to some extent. For example, a southerly flow would typically have south-easterly winds. When we have a particularly large area of HP this displaces more air from its centre to its periphery in the surface layers (at the surface and slightly above it). The backing or cross isobar effect is even greater. Take the T+192 chart below which shows a slack south-south-easterly flow with the HP centred over Germany and Denmark. The winds will be east-south-easterly and the air will be coming from central Europe, let's say Switzerland (I am not going to go into possible Alpine fohn effects which may or may not have a small impact). The immediate source of the air will be from under the HP. The original source would actually be much further east with the air slightly modified but flowing around the southern flank of the HP before it migrated further south. This surface layer would appear to have very little wind to shift it. At this time of year, it is likely to remain very cold and dry with very low dew points. Yes temps would rise briefly above freezing in any sunshine but with severe overnight frosts. In cloudier conditions the daytime temps would be lower but with only slight frosts. Any freezing fog would keep daytime temperatures well below freezing. A rather different scenario to north African zephers (somebody even mentioned Saharan dust!). Of course much will depend on how cold it gets over most of Europe during the next 5 days. If you have followed my daily Euro temp and pressure watches which I post around 0730 each morning, you will see the answer is likely to be very cold. Now let's go through the charts. Another point, I notice that most of the European charts posted on the thread are the default ones from Meteoceil. If you click on "Europe 2" you can get a wider picture (not the northern hemisphere view) but one that goes further in each direction, like the charts I show below. This feature is available for most of the models except UKMO and, strangely, the GEFS ens means. The position up to T+120 is still showing the cold easterly. I pick them up from T+144. The HP has sunk southwards but is ridging across the UK. So, if this verifies, the cold air would be able to stagnate right over us. This continues into T+168. Then at T+192 through to T+216 the flow veers to a more south-south-easterly one. I have already described the likely surface conditions for this period. Then the T+240 chart starts to show two possible much colder evolutions. The main Atlantic LP systems are way out west, closer to North America. The small slack area of LP to our south looks like it will perform an undercut as it can hardly move northwards with the strong build of pressure towards Greenland which developed from T+192 to T+240. It is strengthening a south-easterly flow (with easterly winds) dragging in air from the near continent. If this continued it might re-introduce an easterly. The far more likely evolution going by the T+216 to T+240 charts would be the deepening low heights to spill down into Scandinavia with the Greenland HP starting to exert its influence and we move into phase 2 with the northerly streaming down across the whole of the UK probably by around T+288. The 850s do mix out and we might see them in the 0c to +4c range for a few days if those charts verify. Meanwhile, let's look at the surface temps. ECM do not publish these on their free-to-view Meteoceil charts so I found a similar pressure chart to the ECM 12z T+192 with the GFS 12z T+192. This also has the HP just to the east of us and a gentle south-south-easterly flow. The 850s are quite similar too. The T+192 shows temps across much of the UK around 4c and up to 8c along the south coast. This is a 1300 chart which would be close to max temps, so I include the T+186 charts with 0700 temps which will be closer to min values. This shows most of the country around or slightly below freezing. These charts almost always understate any surface cold so I would say that these are about the highest possible values under the GFS and ECM evolutions at that time. So definitely not mild! ECM 12z Pressure: T+144 T+168 T+192 T+216 T+240 ECM 12z 850s: T+144 T+168 T+192 T+216 T+240 GFS 12z: Pressure T+192 850 Temps T+192 2m Surface Temps at 1300 T+192 2m Surface Temps at 1300 T+186 I believe that the ECM evolution is a complicated one and may not be right but that's more of an opinion and unlike my analysis above, I cannot really back that view up.I know that much of the other 12z model output has been inconsistent. and whilst writing this, I have not yet had a chance to view the GFS 18z but judging by the number of new posts (over 60 in the last hour or so) I'm assuming that it's an upgrade. overall, I firmly believe that the upcoming cold spell will be a good one with a few snow chances. I think that the HP will not sink nearly so quickly and I'm expecting the phase 2 northerly (and possibly a further easterly later on) to deliver something even more special. Cold or very cold throughout but perhaps a couple of slightly less cold days during the transition. I'll be back in the morning with the latest on the HP and the deepening cold block EDIT: Wrong assumption by me. The last half of the GFS 18z is struggling with the phase 2 cold spell. It looks like it makes an attempt to bring in a northerly but then backs off. Where on earth is that Atlantic flow coming from? Some quite extraordinary things going on. The models are going all over the place from D6 onwards for at least the next few runs. Be careful not to over react to a single model run. Now to quickly spin through over 70 posts. I hope there are rather more better quality views expressed.
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    This threads a joke sometimes. Its like the BBC snowatch from 2001. All we need is Bill Farkin & his grebes & seaweed. For those with a nervous disposition & the inability to control your emotions I suggest you avoid the GFS & just view the ever reliable UKMO - which is far less volatile. Snow for many this weekend, slightly warmer next week but feeling colder - then Greenland high opportunities... UKMO 168- cold SE flow, snow possibilities for the extreme NE/Scotland- also primed for high pressure build over Scotland- have a good day .... PS @Gibby- The ECM has been disgraceful post 144 in the last week, the only model coming out of this with any credibility is the UKMO- didnt you base your forecast on the ECM which was clear- no snow for the UK & a SE wind...
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    Please note: I have copied this post across to the "in depth thread" should anyone wish to discuss any points that I have raised and share their views in a less frantic environment DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 5 FURTHER GREAT NEWS - THE DEEP COLD POOL IS MARCHING WESTWARDS INTO EUROPE In the build up to our cold spell, I feel that it will be useful to keep up-to-date with the current and trending temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next few days around 0730 to 0800 (although I am away on a business trip this Friday so no update then and Saturday’s will be around 1300). This will show how the pattern is evolving and allow us to monitor the extent and the severity of the cold that we might expect. Firstly, I simply do not understand some of the negativity on here. Here is a summary of my take on developments. Our weather will be coming from an easterly quarter for much of the next 10 days and we will soon be part of a massive cold pool that covers a vast amount of western Asia, Russia and north-east Europe and now Scandinavia and it’s all heading our way. There is no energy in the Atlantic to shift this at all as far as the eye can see and the surface cold will almost certainly become intense and entrenched. Temperatures almost always turn out lower than initially predicted in this type of set up. There will also be some extremely low dew points and the 850s, despite a greater variability, will be very low at times with several breakaway colder pools likely to head down through the flow. There are more than strong hints of a switch to a broad northerly later in week 2 and later in the month we may see switches between northerlies and easterlies a few times with the HLB somewhere between Scandinavia and Greenland. For more details and analysis of this please refer to my last full report on Sunday (see page 105). Since then everything has been going in the right direction. The models will still fluctuate on the finer detail for the first week (very uncertain where and how much snow we shall get but at least some seems highly likely) and even more so in week 2 nailing down the transition from “cold” conditions to “cold” conditions (no typo there !). At worst, just several days of slightly less cold weather. Now, I shall pick up from my last “check” on page 112. This took us to February 6th. European Surface Temperature Charts: Current "live" Feb 7th 0650 Feb 6th 1250 Feb 6th 0650 Feb 5th 1250 Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to maximums. COMMENT: Just look at how much that sub -20c purple area has expanded. Ahead of that, almost all of Scandinavia except for a few coastal spots is sub -5c with a lot of sub -10c temps. The darker blue shades of sub -5c has moved through eastern Europe and reached central Europe. It's all heading steadily towards the UK. All this can be seen by comparing the two "0650" and the two "1250" charts. GFS 0z February 7th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps COMMENT: Compare today's charts (above) with yesterday's (below). Note the further expansion of the "purple shades" area of sub -20c surface temps with a greater area below -24c and even a patch of sub -32c temps (light grey). The only piece of slightly less good news is that the pool of sub -20c 850s is slightly smaller but this is more than countered by the increase in the area of the sub -8c and -12c temps. There is quite a large area of breakaway sub -12c temps (with a centre of sub -16c temps) moving south-westwards through southern Scandinavia and northern Europe. Another extremely encouraging sign is the re-orientation and path of the sub -12c temps. Note how that part of the pool is now heading straight for the whole of the UK rather than slightly to our south. This change has happened as I predicted simply because of the development and changing shape of the Scandinavian HP pulling the cold through westwards on its southern flank. GFS 0z February 6th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps European Surface Pressure Charts: Current "live” Feb 7th 0650 Feb 6th 1850 Feb 6th 0650 Feb 5th 1850 Current Met Office Fax: 0600 Feb 7th GFS 0z February 7th T+6 GFS 0z February 6th T+6 COMMENT: Our Scandinavian anticyclone has intensified further and has just reach 1049 mb and is still slowly intensifying. It looks like it will reach some way over 1050 mb (perhaps as high as 1055 mb) which is more intense than any of the models were predicting (at least up to the 12z and 18z output yesterday). This should help strengthen the easterly flow and push the deeper cold (surface and uppers) closer to the UK more quickly than predicted. The centre of the HP is still edging very slowly west-south-westwards. I feel that it will maintain a very similar position for many days. The exact orientation of the flow will be partly dictated by the Mediterranean LP which has remained centred over Italy for over 36 hours now. This looks like a highly stable set up in terms of position and longevity. The flow looks like it will be east-south-easterly initially (with due east winds) as it moves into the UK during Wednesday and Thursday. Then, as the deeper cold air pushes around the HP it looks like the flow will veer slightly more to a direct easterly (with east-north-easterly winds). This should produce at least some snow flurries but there may be some snow showers along exposed eastern coasts as soon as Thursday (that's after perhaps a little snow as the stalling frontal system pushes back westwards tomorrow with the colder air already undercutting it). Then we need to look out for troughs and other disturbances running west-south-westwards through the flow. That cold front shown on the current Met Office chart is the leading edge of the much deeper cold air and one to keep an eye on. Overall, everything continues to move in the right direction - there is no need to worry about the variable 850s as they'll be generally low enough for any precipitation to fall as snow from late Thursday onwards as the dew points will be falling to sub zero by then. There will be pools of much lower 850s at times which might introduce greater convective activity - so there will be some good potential for at least some snow. We should be able to get a better idea of this by Thursday. I'll be back tomorrow.
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    Afternoon All- So this is it for Winter- from differing perspectives this could be another roll of the dice for cold ( namely the SE ) or for most the last roll of the dice- We have a window of about 4-6 weeks left where things can be very wintry, however the earlier the better really as post week 3 we do start to see the sun getting higher & daytime potential temperatures creeping up- Again, depending on your location in the UK for the most part this has been a borefest of a winter - I would actually put it on a par with some historic winters for blocking - 47, 63 etc - sadly for us the block has more or less been to far SE, so for places in Eastern / SE europe like Turkey etc this has probably been their version of our 63 - The 500 anomaly plot so far says it all So other that brief continental influences the winter so far has been a non starter, which includes the scottish Ski industry where coverage of snow has been pretty sparse... The dice then, in the shape of the SSW is about to be rolled in the next 10 - 12 days- We have a SSW forecast by the GFS & the ECM is virtually there - bottoming out the zonal mean at exactly 0M/S ( The GFS mean is negative -4 M/S ) GFS V ECM The key landing zone date is Feb 1st as that is the date we go negative - In terms of propergation the standard 10HPA reversal to seeing the core 500MB charts seeing a direct change is usually around 10 days - however sometimes ( & something Im going to look into detail this summer ) is the NH blocking pattern responds quicker to the warming - aided by high MJO activity & higher amplitude phases - so what I would expect to see is a major block forming pacific side - then another block forming Around scandinavia - Perhaps further west.. The models are picking up on plumes of The WAA moving North towards the pole at day 6-8 & are trying to resolve what that means for the formation of the upper high- The GFS 100HPA charts at day 8 go for a split of the vortex with High pressure developing in the location mentioned above- its not a full on split up to 10HPA as the vortex looks to recover post warming- So we are now getting the outlines emerging of a block towards Scandi & a lobe of PV dropping south into Russia- With this pattern things tend to retrograde west in cycles, so cycle 1 this week ( 144-168 ) deep cold may well start to filter into Eastern Europe from that lobe, cycle 2 may well force it west into central europe ( maybe even the UK ) - a third cycle may be a bullseye - essentially what 1 cycle is - is a sharp pulse of WAA moving North / North east with a cut off low dropping south on the Eastern flank , High pressure builds over the top allowing the mean flow around the high to create Easterlies underneath- Because this then ruptures the jet again further west you get another pulse of WAA & another cut off low, the secondary developing high then merges with the first High pressure forcing the cold further west & you get a long draw easterly underneath- What has failed in recent years is on cycle 2 or 3 the jet has been to strong to get vertical WAA so the cut off low sinks SE instead of South ( or even East into the block ) & we miss the boat - So ***IF*** something is going to develop from the East delivering snow to the UK, look for 2 or 3 cycles of 'shunting' cold west for it to happen. Earmarked dates - Feb 5-7 cycle 1, Feb 8-11 cycle 2 ( circa 216-288 ) in the models ) cycle 3 if needed 13-16th.., fingers crossed S
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    DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 9 THE COLD POOL IS LOSING ITS GRIP – FINAL “WINDING UP” REPORT Unfortunately, I am going to have to concede that it now seems highly likely that the winds will veer towards the south during the next few days and mild air is making steady progress through France towards the UK. The pressure pattern is no longer conducive to bringing the cold pool back towards us – we needed a much more east to west orientated HP. It did show a lot of potential a few days ago but things went rather pear-shaped since then. There is no point on my continuing these daily reports, so I shall do a shorter closing analysis. In the highly unlikely event of a dramatic change for the better, I will be back! Now, I shall pick up from my last “check” (on page 19 of this thread) which was a “bumper” edition. This took us to February 11th. European Surface Temperature Charts: Current "live" Feb 12th 0650 Feb 11th 1250 Feb 11th 0650 Feb 10th 1250 Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to maximums. COMMENT: The deep cold (purple area) has hardly weakened but it has not progressed any further west in the last 3 days. The cold pool in central and western Europe has weakened slightly and is being steadily eroded from the south and south-west. Daytime maxima have been rising but the nighttime minima have remained quite low. All this can be seen by comparing the two "0650" and the two "1250" charts. GFS 0z February 12th T+6 European Charts: GFS 0z February 11th T+6 European Charts: 850 Temps 850 Temps COMMENT: Compare today's charts with yesterday's. The main pool of 850s with sub -8c temps has actually expanded southwards but it has weakened considerably on it's western and south-western sides. The breakaway area of sub -12c temps over Scandinavia and Denmark has mixed out and only a thin slither of sub -8c temps remain. The 0c to +4c temps have pushed northwards through France during the last 24 hours. European Surface Pressure Charts: Current "live” Feb 12th 0650 Feb 11th 1850 Feb 11th 0650 Current Met Office Fax: 0600 Feb 12th COMMENT: The HP has only weakened slightly but it has taken on a far more north to south shape assisting with the southerly breakdown. The warm front shown on the fax chart is the leading edge of the milder air. Overall, it was fun producing these reports when there seemed to be so much potential but it has been hard to put a brave face on things during the last couple of days. I do have a stubborn streak and only gave up on this cold spell long after many of you guys had and after defying the changing model output! We now need to focus on the chances of our next cold spell for later this month. I'll be back this evening with my latest full weekly report and I'll have a look ahead then
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    Just a quick one from me for a change as I do need to run my full-time business as well! I simply do not understand the dire mood from many posters this morning. I was very busy writing my two posts and didn’t check the 0z (and 6z) runs properly until just now. I do not see anything “mild” in any of the outputs – this week, next week or beyond! The models are really struggling with the transition from phase 1 of the forthcoming cold spell with the easterly to phase 2 with a broad northerly (and possible further easterly after that). There are the usual timing issues. Several models, like ECM and the GFS 6z, are very progressive in sinking the Scandi HP from around D5, several others do this after D7 and several hardly show this at all – see the NAVGEM, GEM and JMA. We cannot exactly say how the UKMO will go after D6 as its main output stops there (those tropical T+168 charts do not show the key areas to our north and east) but the latest MetO update suggests that it might be somewhere in between. Sorry, no time for my full cross model analysis. Let’s go with the flow (not quite literally!) and assume a transition from around D7 to D10. These models sink the HP somewhat but NOT completely. A south-easterly sets up for quite a few days. Forget about the uppers – this period will be all about surface cold which I am almost convinced will, yet again, be hugely under estimated. Much of Europe will be at least partially snow covered by then – we may even have had some ourselves. The cold will be entrenched. Even with the supply of the intense cold feed from the north-east being cut off for a while, there will be plenty of deep surface cold around. I’ll stick my neck and say that any south-easterly will see temps close to 0c for much of the time across most of the UK! If that LP to the south-west shown on models like the 0z ECM around D6 materialises, it could actually bump into the cold and produce a significant snowfall. It might even go on eastwards to undercut the HP and strengthen the easterly. Remember, this evolution may not happen at all. I have suggested in my two reports this morning that the HP may well hang on stubbornly close to its current position. This would maintain a cold easterly for much longer and with access to top ups of further deep cold from the north-east. After this, everything points to our north and north-west and HLB building around Greenland. Whether that’s the Azores HP ridging northwards or the Scandi HP ridging west-north-westwards is yet to be decided. I’m running out of time now – so I’ll post just one chart from the JMA which actually has one of the more continuously colder runs. Just for fun this is yesterday’s 12z T+204: Spot the world record Greenland HP of 1085 mb! The JMA model has a serious problem with overstating the pressure over the high Greenland plateau – probably over 25 mb lower when adjusted to mean sea level pressure. The serious part of the run (with the first part updated with today’s 6z output) is that it shows cold throughout. Overall, I remain totally optimistic that this will be a prolonged and memorable cold spell, with perhaps, phase 2 delivering more snow than the initial easterly. Loads to watch out for. So please enjoy it all and do not get hung up with just a few temporarily downgraded runs – which may or may not verify. EDIT (1): @Chris.R Your excellent link to the Euro pressure and temps etc is very useful but only tells half the story. There are many locations in that region where there are only small towns and villages . We hit 1050 mb about an hour ago (in line with my predictions in my update this morning) and our Scandi HP is still slowly intensifying. I still predict around 1055 mb some time tomorrow - so the models are still playing catch up with the strength of the HP, the intensity and extent of the surface cold and also (contrary to popular belief) the 850s as well. I'll provide a full update around 0730 tomorrow but here are 2 very current pressure and temperature charts to go on with and for those still saying "what cold?" the deep cold has continued its progression westwards during today. The 1650 chart was not far off the "maximums" for today + the live chart. Note not just the purple but also the blues: European Surface Pressure Charts: European Surface Temperatures Charts: Current "live” Feb 7th 1650 Current "live” Feb 7th 1550 Before some you guys post some gloomy one liners and the most negative chart that you can find, I suggest you always quickly check the current and very short term charts and you will be far more upbeat (or at least you "should" be) ! EDIT (2): I will add the two latest updated Met Office fax charts below as soon aon as they come out (due around 1500 to 1600 but seriously delayed today). They will give a good indication of the UKMO position for D4 and D5. The MetO written update does mention a brief "less cold" south-easterly followed by a renewed easterly with some very cold conditions. This would be a "middle of the road" solution. So come back and check shortly. MET OFFICE 12z T+96 SAT FEB 11TH MET OFFICE 12z T+120 SUN FEB 12TH TO FOLLOW SHORTLY COMMENT:
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    Some absolutely outrageous comments this morning in here it's an embarrassment at times im afraid. Anything past 120 is fi at the minute, a warming of the uppers is a good bet for next week, but that means absolutely nothing for anything past tue or Wednesday at the very latest, we await new signals from the models every day, and until the models pick up on the way forwards after the initial south-easterly sun/mon then there's absolutely no point in throwing toys about, we have lots of interesting things taking place at the minute not to mention the strat warming which has only just occurred , along with an active mjo for the first time this season so let's just allow the models come to grips with things rather than thinking a chart at t150 hrs away is a dead cert. Listen to the people in the know, don'tget hung up over every run, I can say this until I'm blue in the face and it won't make any difference what so ever so what's the point.
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    That assessment is a fair way off - I would say widespead -5c departures away from the Norm - maybe 6/7 in the NE- The ECM in particular bringing plenty of snow to the NE & scotland- it cannot snow everywhere- every evolution has its focal points.... obviously the further south & west you go the signal is slightly muted, so for the SW / wales it may appear not so great, however many an easterly has started dry with -10c in the NE - to then get a bit of kink in the flow to transfer the deep cold & snow SW across the pennines towards wales etc... dont be to downbeat- Also I would say 'significant' moves to a longer cold pattern today & with 96-120 hours to the Easterly- plenty of scope for incremental moves south, as well as major room for colder developments 168-216--- best S
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    Lots of uncertainty but signs that the atmospheric circulation is going to mirror stratospheric turmoil and wind itself up for some elastic band rebounding that suggests some interesting and contrasting surface detail fall-out to come for the last third of winter This is one of those occasions where falling torques and atmospheric angular momentum tendency in the first instance and then a consequent sharp rebound of torques and atmospheric angular momentum in the second, might engineer catalyst to snap the NH pattern out of its seasonal rut. Cued by tropical forcing in the Indian Ocean, -ve balance of frictional torque has been leading mountain torque decisively downwards over recent days. A considerable -ve mountain torque has occurred over the Rockies and rapid removal of westerly winds from the atmospheric circulation is occurring. This has signalled a drop in relative angular momentum tendency With (approx) two day lag plot showing the Global Wind Oscillation heading towards low amplitude Phase 1 Taking into account response timelines to -ve mountain torque this advertises an upstream amplification over the Pacific to occur around the 6 day period which will have downstream ramifications in terms of retracting the Azores High westwards and taking the Jetstream southwards across the Atlantic as fuelled by the displaced Canadian lobe of polar vortex. No surprise to see some distinctly unpleasant weather modelled in the next weekend period in the first stages of this process However, the upstream jet, is set to decelerate rapidly as pressure rises over the Pacific and re-build the Aleutian Ridge. In the Atlantic sector, the retrogression of the pattern will tend to angle the Jetstream more NW/SE and, conceivably, enable build of pressure over Scandinavia. With time, as the disrupting trough gets separated from the Canadian lobe of vortex, downstream amplification from the Pacific sector becomes possible at the same time as the wave 2 response is activated by rising pressure over Scandinavia to work on the vortex in tandem with the Aleutian Ridge. It is key at this point that the vortex is sufficiently weakened to allow the bleeding of secondary systems to be cut off from the Canadian lobe - and hence terminate the thermal gradient. So much for the extra tropics. Returning back to the tropics, we have to watch eastward propagation of the MJO towards the Pacific starting to act constructively on the pattern in terms of increasing downstream amplification. With angular momentum, what goes down goes back up again to balance the global windflow budget, and with total angular momentum levels close to parity... then a logical correction to reflect the background ENSO neutral ocean base state can neatly be supplied through eastward moving tropical forcing. What does this mean in possible synoptic terms? It firstly bolsters/re-enforces the inflection point of downstream amplification into the Atlantic as, ultimately, transferred by a decelerating jet from the Pacific - which then encourages a follow-up link up (over the top of cut-off disrupted troughing heading into Europe) to the pressure rises over Scandinavia. Meanwhile, with (hopefully) a split enabled in the vortex, the chances of the jet crossing through the northern arm with spoiling energy to inhibit amplification are reduced (also assisted by tropical signal progressing through Phases 7/8 which would teleconnect to an increasing -NAO signal and help back cold air advection west) This is of course the ultimate prize scenario of what *could* happen through February. Whole timing of all this beyond the point where troughing may start disrupting and reduce the vigorousness of the Atlantic is obviously uncertain this early, and of course much depends on both emerging stratospheric signals and medium to longer term tropical forcing signals both sustaining, and, very preferably upgrading. Its a case of looking to an orbit of the GWO to Phase 2 (shaping the Atlantic ridging and as already given credence by latest GFS 06hrs) and then looking to the stratospheric fall-out of the tropospheric uppercut and westward encroaching Scandinavian ridge as tropical forcing moves eastward to the Pacific and hopefully maximised amplification as atmospheric angular momentum tendency returns the GWO through to Phase 4 But whilst we are familiar with what can go wrong will go wrong, lets consider for a change that this process does, on occasion work the other way too. There is feasibly reasoned GSDM extra tropical and tropical support for both the tropospheric and stratospheric possibilities - and with just the last few weeks of February left of official winter, and whilst we cannot control the elements, frankly there is little to lose in approaching the evolution with a mind-set that is otherwise Late edit: GEM 12z and GFS 12z are also trying to read the longer term script...
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    I haven't been able to post much this week but I have been keeping a continual eye on the models. The wave 2 split in the vortex modelled initially last week has been reduced in intensity and hence we have seen fluctuations in the intensity of the Atlantic inroads. But crucially it is still there and is very much trop based so it is unlikely to disappear from the models. A week on from this being initially modelled and we are closer to achieving a classic easterly - it may or may not occur but we are still very much in the game. Spotting a split that upwells into the stratosphere gives us an opportunity to predict this type of scenario well before it is modelled in the troposphere so if anything can be learnt at this point it is to keep a constant look out for this type of scenario. I still think that there is a good chance of special synoptics that we don't see too often - we still have the tickets for that once in a while lottery.
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    DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 8 - ONE OFF BUMPER EDITION INCLUDING DEW POINTS AND NORTH-WEST FRANCE FOCUS THE COLD IS MORE MARGINAL THAN ORIGINALLY EXPECTED BUT IT IS NOT ALL BAD NEWS In the build up to and during our cold spell, I feel that it will be useful to keep up-to-date with the current and trending temperature and pressure changes in Europe. I will try to produce these on a daily basis for several more days around 0800 - although I was away on a business trip from Thursday (so no report Friday) and just got back at 1100 today until Saturday (so this one is around 1400. We can see how the pattern is evolving and monitor the extent and the severity (or lack of it) of the cold. Firstly, when I drove back from Warwick to Exmouth this morning there was almost continuous very light snow (with patchy settling). This is not the thread to expand on this - so for those interested, at 1215, I added a post to Tamara's "single status report" that she started yesterday. I also congratulate NetWeather on their latest radar, which seems to be much more accurate for differentiating snow (pink) and rain/sleet/snow (green). Whilst driving back, I thought that we should have a closer look at the dew points and the temperatures in north-west France which might be crucial in dictating which side of the two "marginality" thresholds we might sit on in respect of snow (rather than less wintry precipitation) and whether any snow settles. I will not have the time to do this every morning but it's really important right now. Now, I shall pick up from my last “check” (on page 10 of this thread). This took us to February 8th. European Surface Temperature Charts: "Current "live" Feb 11th 0650 Feb 10th 1250 Feb 9th 0650 Feb 8th 1250 Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to maximums. COMMENT: Well isn't this just so very frustrating! The cold block has now extended all the away to western Europe and most of the UK and Ireland but at the expense of the deep cold. As I said in my last two daily updates (on Wednesday and Thursday) there is one unwelcome intrusion. A wedge of less cold air is located between eastern Scandinavia and the coastal part of north-west Russia. This air travelled around the top of the HP and pushed southwards on its eastern flank. As it comes off a relatively warm sea it has effectively divided the block and prevented the really deep cold from spreading further west. Now that the HP has moved very marginally southwards (not nearly as far as predicted - see below) you can the gap closing again. Will this be a little too late or might we see a new westward progression by tomorrow? The sub -8c and sub -4c temps have moved further west across into central Europe. Looking at the current pattern, there is a good chance that these might move even further west during the next two days - that'll make the short-term forecasts more interesting. All this can be seen by comparing the two "0650" and the two "1250" charts. European Surface Dew Point Charts: "Current "live" Feb 11th 0650 Feb 10th 1250 Feb 9th 0650 Feb 8th 1250 COMMENT: Given how marginal conditions are for snow in lowland UK, I am including some dew point charts for the first time. The European charts above for dew point temperatures show a similar pattern and progression to the surface temperatures. The sub -4c and sub -8c dew points were at their most extensive and further west on this morning's 0650 chart. The critical sub 0c temps cover most of France and some of the UK. I also show the current "live" and the 0650 charts for UK surface temps and dew points below. The dew points are not quite as low as yesterday morning but are generally between -1c and +1c. There are some lower values just across the Channel. If the winds do veer more easterly from north-easterly later today (as predicted first thing this morning - I haven't checked the latest forecast for those fine details) then the south-east will immediately benefit from lower surface temps and lower dew points - these may then spread across most of southern England. More on this below. UK Surface Temperature Charts: UK Surface Dew Points Charts: "Current "live" Feb 11th 0650 "Current "live" Feb 11th 0650 GFS 0z February 11th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps COMMENT: Compare today's charts (above) with yesterday's (below). Note that the "purple shades" area of sub -20c surface temps (and lower temps) remains towards the north-east of the block. The area of sub -4c and sub -8c temps over Europe has changed little (finer detail described above). The 850s are a little more interesting and slightly better news ("if" the pattern persists). The pool of sub -20c temps in the north-east has intensified again with a wider area below -24c and even some sub -28c and sub -32c temps appearing . The area of sub -16c temps has also expanded. The sub -12c temps are little changed in the main pool but have weakened slightly in the breakaway pool over Scandinavia and Denmark. There is still a good area of sub -8c and particularly sub -4c temps in our vicinity. These have pushed southwards through Ireland. GFS 0z February 10th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps Focus On North-West France (+ links to forecast charts): Current "Live" Surface Temps 0650 Surface Temps Hourly Forecast Precipitation Hourly Forecast Surface Temps http://www.meteociel.fr/modeles/arome.php http://www.meteociel.fr/modeles/arome.php?ech=3&mode=141&map=0 COMMENT: I feel that right now we need to focus on the conditions over north-west France as this will directly impact on our short-term changes. I show the current and 0650 surface temps over France (which includes much of England and Wales as well). The surface and dew point temperatures are generally slightly lower in north-west France compared to those over most of England. A veer in the winds to the east will import these across to us. The last two charts are short-term forecast for precipitation and temperatures. I still haven't mastered the techniques to copy across the charts with the 1 hour time change scroll down features. So I show the two recent charts + links to the full "scrollable" charts. I had a look at these yesterday when I was away and I noted that the forecast is for slightly lower temps today. This is good news for tonight and tomorrow (if we get the more direct easterly). More importantly and just confirmed to me by @Nouska (thank you) the large temperature rises forecast for central and northern France have been very much downgraded and delayed. This is where the charts (for most of the models) have been showing the winds veering into the south by Monday. I felt that this was not only far too progressive but also there would still be plenty of surface cold to shift. I still think that there is a possibility of the milder air climbing over the cold surface air (which could possibly produce further snowfall) but would also further delay any warm up. European Surface Pressure Charts: Current "live” Feb 11th 0650 Feb 10th 1850 Feb 10th 0650 Feb 9th 1850 Current Met Office Fax: 0600 Feb 11th GFS 0z February 11th T+6 GFS 0z February 10th T+6 COMMENT: Yet again, more good news. The HP has only lost a little of its intensity (just 7 mb in 48 hours) and has only moved slightly south-eastwards - far less than predicted by the models only two days ago. it still has that annoying south or south-east ridge (that allowed the north to south flow on its eastern flank that brought in the milder sea air to the east of Scandinavia) but this is far less pronounced now = good news for reducing the amount it holds back the deeper cold to the east. Even better news (perhaps) is the ridge building westwards to the north of Scotland with even signs of a separate cell of HP emerging there. We have lost the Italian LP although lower heights remain across much of the Mediterranean. There is a wedge of LP across central and northern France. It is this that will be critical in determining how long the cold lasts into next week. It may hold up the veer of winds to the south or we may see a more south-easterly flow still import the cold air from central Europe. We might even maintain the easterly. A truly fascinating pattern that needs to be watched very closely. Looking further ahead, I see that we have a real impasse with the models in disagreement beyond D6. I think that they will struggle with D2 to D5 as well! No more on this now but I will pick up on it in my weekly report tomorrow evening and look at the Jet Stream and broader pattern changes as well. Overall, the news is definitely not nearly as bad as some might have been expecting. Can we get some more snow in the next day or so? Will we loose the cold quickly, slowly or not at all? Will we still get the phase 2 cold spell later this month. Keep watching. I will do a briefer update tomorrow morning.
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    If the UK doesn't see some very cold temps and snow in the next few weeks then I'm going to call in a priest to perform an exorcism as there's clearly some dreadful entity stopping this. The MJO forecasts continue to increase the amplitude of the signal with it moving into the favourable 7 and 8 phases. Add to that a weakened PV then surely even the UKs cold and snow force field will be breached!
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    DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 7 MIXED NEWS - THE COLD POOL MOVES IN BUT THE REALLY DEEP COLD LOSES SOME OF ITS INTENSITY In the build up to our cold spell, I feel that it will be useful to keep up-to-date with the current and trending temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next few days around 0730 to 0800 (although I am away on a business trip from later today until Saturday – so no report on Friday and the next update will be on Saturday around 1300). We can see how the pattern is evolving and monitor the extent and the severity of the cold. Now, I shall pick up from my last “check” (on page 150 of the previous thread). This took us to February 8th. European Surface Temperature Charts: Current "live" Feb 9th 0650 Feb 8th 1250 Feb 8th 0650 Feb 7th 1250 Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to the maximums. COMMENT: Although the cold pool has continued to advance across Europe the area of deep cold has lost some of its intensity. As I said yesterday, the air flowing around the top of the HP to the north-east of Scandinavian and around the north-west Russian coast has been coming in off the warmer sea from the north. This has eroded some of the deep cold in that part of the pool. The remainder of the sub -20c temps (purple) is now more or less stationary. The sub -8c and sub -12c temps have edged further west and south-west. The better news is that the area of sub -4c temps has now spread across central Europe and the sub 0c temps now envelope western Europe and the UK (as near minimum temps but the maximums will be in the 1c to 5c range for most parts today). All this can be seen by comparing the two "0650" and the two "1250" charts. So, it will be cold or very cold for a few days (or longer - see final comments) but not quite as extreme as might have been expected several days ago. GFS 0z February 9th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps COMMENT: Compare today's charts (above) with yesterday's (below). Note the "overall" further expansion of the massive cold pool in terms of sub -4c and sub -8c surface temps (mid and dark blues) but less extensive sub -20c temps (purple). The area of sub -24c temps (dark purple), sub -28c temps (pink) and sub -32c temps (light grey) in the north-east of the block is little changed. Scandinavia is colder with an expansion of sub -20c temps there. The sub -12c, -8c and -4c temps have progressed further westwards through Europe. Similarly, the overall huge pool of 850s with sub -8c temps has expanded but the area of deeper cold has changed little with the pool of sub -20c 850s remaining in the north-east well away from Europe. The region of -12c temps is slightly smaller in the main pool. There is still the area of breakaway sub -12c temps which remains just to our north-east (the small sub -16c has gone). The area of sub -8c temps ahead of this has now extended across eastern UK and the -4c temps now cover almost all of the country. GFS 0z February 8th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps European Surface Pressure Charts: Current "live” Feb 9th 0650 Feb 8th 1250 Feb 8th 0650 Feb 7th 1250 Current Met Office Fax: 0600 Feb 9th GFS 0z February 9th T+6 GFS 0z February 8th T+6 COMMENT: If the news wasn't quite so good for the temperatures, it is better for the pressure. The Scandinavia HP continues to be more intense than the models were predicting. It reached a peak of 1057 mb at 2250 and for several hours last night at Drevsjo in central Norway. Although this has an altitude of 672 metres, Meteooceil do state that all their live and recorded figures shown are automatically adjusted to mean sea level readings (where they would have reduced all the readings by roughly 1.2 mb per 100 metres). A wider area there and up to northern Norway has seen pressure levels stabilise between 1050 and 1055 mb for much of the last 24 hours. Two more bits of better news. The central position of the HP has stabilised over central to northern Sweden and Norway. Rather further north than the models were predicting. The shape of the HP has been improving too. Yesterday, I was concerned by the strong south-eastwards ridging. This had meant that the deep cold pool had further to travel around it or might be blocked from its westward progression. Well this ridge is becoming less pronounced and is slowly edging westwards. Ideally we want a flatter southern flank to give a more direct easterly flow through Europe. The LPs to the south remain in a good position to prop up the HP. The central Mediterranean LP (just west of Italy) has remained more or less stationery, perhaps deepening very slightly. I mentioned that there were signs of another LP forming over the Black Sea and that has now happened. The position and shape of the LPs is also very important in determining the precise direction of the surface flow over the next few days. It looks fine for some time (in maintaining the easterly) but we need to see if a new trend starts to show up.. Overall, I must admit that it is disappointing to see the the really deep cold become a little less intense. It is difficult to be precise about how cold the UK will be over the next few days in terms of the marginal temps at the surface, the 850s and the dew points for snow, sleet or cold rain. There are likely to be colder patches and some snow, particularly away from the exposed coasts but all to play for. FINAL COMMENT: Like the rest of you, I was disappointed to see that there is likely to be a delay in "phase 2" with the northerlies and Greenland HP perhaps not arriving until later in the month (assuming that the background signals still favour HLB at that time). This explains the change in the model output in the last 2 days. There have been some swings back and forth and phase 2 could still evolve more quickly. That Indian Ocean influence might not be so disruptive but we'll need to watch the updates from the likes of Tamara and GP on this. I still believe (perhaps too stubbornly) that the cold block is a massive one (less really deep cold is not too important - it's the extent of the surface cold that is vital) and will take a lot to shift. The Jet Stream is weak and meandering and the Atlantic remains extremely weak. If the PV lobe does transfer east towards Siberia, the wedge of lower heights is likely to push southwards over north-west Russia and northern Scandinavia. This would displace the HP somewhere to the south - the models currently favour the south-east but due south (perhaps right over us) or more westwards to our north or north-west are also possibilities. Right now the HP is intense, stable and stationary. I feel there is a good chance that it will hang on in a similar position until much later next week. Then, as in January, we might narrow the gap between this cold spell and the one predicted to follow. I'm a little less bullish but not defeated! NEXT UPDATE: Saturday around 1300 - no report tomorrow (Friday) as I'm away on business. EDIT: I will be more than happy if someone else wants to do an update tomorrow - at least with the liver pressure and temperature charts so that progress can be monitored while I'm away.
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    Morning All- Just a quick update from the other nights post- nothing much has really changed - The second wave of warming is really coming into view now - very similar to the way the last one was modelled, initially progged to send the zonal mean into deep negative territory, the last 48 hours have seen the overall forecast to continue to run along the same timeline with a 'slight' moderation of the negativity of the zonal winds- The mean (GFS) drops to + 2M/S on the 22nd- however as with the first warming assisted by the MJO the tropospheric response could well be more immediate -last time relating to the height anomalies - they had responded & built when the zonal wind had reached the +10M/S line (ave for mid Feb is ~ +23M/S) The CFS again is very bullish about negative territory & whilst modelling wise it doesnt deliver 10HPA resolution particularly well - generally overall this winter in terms of its forecasts of 'shape' of zonal wind trending V actuals has been pretty good- so it could all be sematics as to whether we actually tick the 'final warming' box- its the steep decline towards zero M/S thats important & of course hopes of a slower / non existent PV recovery.... ( CFS is in pink - GFS ens in Green ) As highlighted then the numbers look good & the magical 0M/S line may yet again be breached- however from a trop point of view the guide for me in terms of what we may well see develop @500MB is the 10M/S time line ( again assisted by the MJO ) - forecasts for this are 17/18 Feb so allowing for the slight lag of height anomalies building we would see the NH profiles to start to look on 17-19th- focussed on positive heights over greenland & in the atlantic with of course deeper troughing trying to filter into Scandi- a relative rarity this winter-that should put the UK in the frame still for getting cold late next weekend ( timed nicely for my 3 weeks off !!) -The ECM strat forecasts are mostly onboard with the forecast although im expecting lower zonal wind forecasts at day 10 when berlin updates today - yesterdays 10 day 100HPA forecast perfectly depicted the flow allignment highlighted above.. If we also review the last few days modelling ( without posting to many pics ) - the ECM in particular has been to progressive with the South easterly warm up, initially progged for Sunday- its now more Monday & we keep a continental influence for the whole week, so frosts by night however a higher diurnal range- Snow over the weekend again looks more widespread than first modelled.. I guess somewhere at elevation in the UK will breach 10cms - Im expecting a dusting here - with peak availability over the UK being Friday 00z to sunday 12z before the slightly less cold uppers filter NE from Kent... have a good day S
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    GEM has that stalled out shortwave in the almost optimium position- !! A SUPER block developing in the atlantic !!
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    DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No.3 – FURTHER EXCELLENT PROGRESS In the build up to phase 1 of next week’s widely predicted cold spell, I feel that it will be useful to keep up-to-date with the current and trending temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next few days. This should help to show if the pattern is likely to evolve favourably (for coldies) and to monitor the extent of the cold that we might expect. Now, I shall pick up from my second “check” on page 81. This took us to February 4th. European Surface Temperature Charts: Current "live" Feb 5th 0650 Feb 4th 1250 Feb 4th 0650 Feb 3rd 1250 Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to maximums. COMMENT: The good news is that the deep cold (purple) over north-west Russia is slowly intensifying and very importantly it is taking on a new “east-north-east to west-south-west shape - instead of north to south. The temps are slightly less low on the south side of the pool but lower to the north. It is edging slowly westwards. All this can be seen by comparing the two "0650" and the two "1250" charts. This is a key area to watch over the next few days as the predicted synoptic pattern develops. Further south and west, the area of lighter blues is also becoming more extensive again GFS 6z February 5th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps COMMENT: We can compare today's charts (above) with yesterday's (below). The surface temps in the purple shades has intensified with the area of sub -20c surface temps marching towards northern Scandinavia. The pool of sub -20c 850s has also expanded with a strong push towards Scandinavia. With the developing synoptic pattern (see below) this progression will almost certainly continue. The "green" warmer area to our north continues to be squeezed out and has almost disappeared. GFS 6z February 4th T+6 European Charts: 2m Surface Temps 850 Temps 500 hPa Temps European Surface Pressure Charts: Current "live” Feb 5th 0650 Feb 4th 1850 Feb 4th 0650 Current Met Office Fax: 0600 Feb 5th GFS 6z February 5th T+6 GFS 6z February 4th T+6 COMMENT: For the first time we can properly see the new cell of HP building down from the north off the north-west Russian coast. It is ridging south-westwards into Scandinavia. The old southern cell of HP has been pushed further east. You can see the two LPs to the south already undercutting and supporting the HP block. All this bodes well for later on. Overall, the building blocks are there and all of my indicators are moving in the right direction for coldies. The “easterly” is on its way! I will be back with my full weekly report this evening, which I shall thoroughly enjoy writing up during today.
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    One of the better posts I've seen for a bit of realism. I know I've been a little quieter than usual this season but a large part of that is because some of the expectations have been set way too high from how we were spoiled by spectacular Synoptics through the 2009-2013 era. For anyone old and cynical enough to remember the old BBC snowwatch days, we would have cried out for Synoptics such as those shown in the day 6-10 period even at Day 16, just for something to talk about. Most of the time it was Steve trying to keep the mood buoyant, Nick seeking kickstarter funding for his subscription Prozac helpline, and Dave Allen updating us nightly on the progress of his Grebes. We know we're heading for a dip in temperatures and of course we should aim for the stars, but realistically an easterly with sub -6c uppers should be something that we should be grateful for - though I do understand the temptation to be downhearted if every cold event is not a December 2010 for those newer to all of this. But of course what we're all hoping for is an Ian Brown-esque WTF moment from @bluearmy as he gallops off the fence at the sight of the record-breakingly GEM-lead cold on the 0z suites...maybe that's beer induced hope talking. SK
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    Is it safe to enter yet?! I tripped over quite a few toys on my way in! Yet more hysteria this morning just because we might get some warmer uppers next week. For gawds sake can people not just enjoy the ride rather than obsessing about whether they will receive a flake of snow?! I agree 100% with some of the posts on here this morning that both the ECM and GFS have not exactly covered themselves in glory this winter, and especially more recently the ECM output seems to have been woeful. The weekend is not yet nailed down in terms of how cold and how snowy it will get yet people are still obsessed with a 'warm up' next week! @Bring Back1962-63 continues to post some excellent summaries as to how things are panning out in the immediate future, and what is clear to me is that the models across the board are continually underestimating the block! Even if we do have to suffer a period of less cold uppers next week, the Atlantic is DEAD! DOOMED! GONE! It therefore follows that it won't be long before we start seeing some more favourable cold charts appearing in the outlook, and their associated increased risk of snow. I have not seen a single chart posted today that suggests it will be 'mild' at the surface anywhere over the UK in the next 10 days, and to suggest the METO will have egg on their face after a single GFS run that shows freezing cold (at the surface) SE winds next week is just laughable! So in summary enjoy the ride people! It is about to turn a whole lot colder and many of us will have seen some snow by the weekend. After that who knows, but there is one thing I am sure of - the words 'at least it will be mild' will not be uttered by a single forecaster over the next couple of weeks AT LEAST and so even if I do not see another flake of snow this winter, I am very grateful for that! Now who's for a round of 12z upgrades?!
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    Big up the ECM 120 Greenhithe cold pool !! Yeah ! @chionomaniac
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    Thus far the ECM has played virtual second fiddle to the UKMO - yesterdays T96 didnt have a deep an upper air cold pool diving through Europe -today it has The good thing is the OP 'should' be a clear outlier at day 6 & 7 as the other runs may well bring those deep cold uppers through holland making a significant difference to the T2ms Its been UKMOs winter- lets hope these past 3 days & the forth coming few are its crowning glory!!! UkMO day 7 is DEEP cold S
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    As some were fretting over the ensembles I saved yesterdays mean and im glad I did. Yesterday 0Z mean for Feb 9th. Todays mean for 9th Feb.
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    Some strange posts especially from MVH. Im not going to explain why again but the way some use the ensembles is wrong in my opinion especially when we have blocking to the NE and a possible E,ly. Lets start by addressing some of the comments that the ECM Op is likely to be wrong. The ECM/UKMO have been extremely consistent at this timeframe. So why we you prefer to go with the ensembles which have the starting data altered, ran at lower resolution? Anyone who has anything negative to say about the models this morning clearly were not around in the 1980s. Im not saying a big freeze is on its way but at the moment these charts have me drooling.