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  2. The ecm continues to disagree with GFS on the evolution of the upper pattern between T96 and 120 and in particular the orientation and position of the Atlantic trough and Greenland/Iceland high cell. Thus the ecm interpretation allows the European trough/cold conduit further west and of course at the same time alters the surface analysis in the eastern Atlantic.Thus at T120 it has a front straddling the middle of the country dividing the cold air to the north and warmer further south with a fair amount of snow in northern England. Obviously the detail of all of this is a long way from being decided
  3. We have been really spoilt in spring in recent years for warmth though. I wonder if we thought it was normal when it wasn’t especially 2011, 14, 17. As you say though 2013 you knew where you stood with the cold
  4. Whilst ec disagrees with the other models and the other models disagree with themselves, the modelling continues to be of restricted assistance re the Easter period and indeed even the middle part of next week! some part of the ec run will not be correct -Southern coldies hoping that it’s the low digging too far sw and not getting east at a low enough latitude to continue CAA. anyway, whilst the direction of travel in the 5/10 day period remains elusive re surface detail, the ec 46 continues to show that spring temps remain unlikely throughout Europe in April - below average out to spring bank holiday on that model. with large parts of the states also showing similar, perhaps 2018 will be remembered as the year without a spring..........
  5. Solar and Aurora Activity Chat

    4 days blank, 45 for 2018 55% Solar flux 69
  6. Dry mostly cloudy start Temp 6.9c
  7. I like your point about August equilibrating summers - it often feels like a reminder that autumn is coming and September the reverse that summer is hanging on ...
  8. Today
  9. This morning's updated fax charts 00 Saturday > 00 Monday And satellite for 0530 (courtesy DSRS)
  10. North American Weather (U.S.A & Canada)

    Another cold plunge over North America
  11. GFS continuing it's shift away from very cold weather shifting it generally further back north as a new low develops to the south west of the U/k and moves north east slowly killing the cold off eventually away from Scotland. So if it's right cooling down for only brief spells away from Scotland. UKMO more positive in bringing cold too early for ecm.
  12. Morning all, Up early , with a cuppa and a Belgian chocolate cereal bar ( keeping the talk of nutty bars, going ). Agree with JennyJane, yesterday, still felt cold ( keeping it weather related!! ) and despite heating being on, couldn't get warm, in our lounge. Probably due to builder ( doing bathroom, adaptation ), unavoidably, in and out of the front door, fetching tools and materials, from his van. Very noisy yesterday, lots of drilling and banging, with a couple of "sparkies" connecting up electrics, for shower unit. Colette and I have chosen tiles and flooring, for Wet Room now, which should be completed, in just over a week. Managing " bathroom arrangements" at night, ok. Does remind me of those "dark days", when I first came out of hospital, 2 years ago. Need to get some more of those cardboard bottles, today, @ 65p a throw, this toileting business, isn't cheap!! Still trying to keep it "weather related", most overnight model runs, paint an unsettled. coldish picture, as we head towards, Easter weekend. With height rises to our W and NW and trough diving SE, across UK. Can us "coldies", squeeze out a white "Good Friday" or Easter weekend? One last hurrah, perhaps?? Hope you all enjoy, your day. Regards, Tom.
  13. Dry cloudy and mild start after light overnight rain Temp 6.5C, low 5.4C, Barometer 1000mb falling, Wind F4 SSW, Rainfall 0.2mm
  14. At 00 the surface analysis was quite complex with a series of fronts traversing the UK with a low 992mb over south west Ireland. Further to the WSW of Cornwall there is a wave that is about to rapidly develop. The fronts duly clears most of the country by now whilst the low over Ireland tracks north east and as mentioned the wave to the west is intensifying rapidly as it moves east/south east to skirt Cornwall by 1800 today So in a nutshell rain will quickly clear the east this morning whilst rain associated with the low will affect N. Ireland and Scotland clearing by the middle of the afternoon. At about this time rain and strong winds.associated with the developing low will impact the south west During the evening and overnight this rain will spread to south Wales and further east By this time clearer and colder weather is into N. Ireland and Scotland. The sequence Through Saturday the intense low to the south west tracks rapidly south east into the Mediterranean under the auspices of the jet whilst the other low continues it's journey away to the west of Norway. Essentially this leaves England and Wales in a slack gradient and mainly cloudy with light rain which is slow to clear and more concentrated in the south with brighter showery weather further north in a light westerly. Sunday is a fairly quiet day of sunshine and showers as the Azores ridges north east but at this point I think it's worth a look at the bigger picture, particularly upstream where the ridge in eastern North America is starting to intensity and release a fragment of the vortex to track south east as a very influential upper trough. Monday starts off in similar vein to Sunday but the aforementioned upper trough has continued to track east, dare I mention two energy flows?, and the associated surface low and fronts associated with it are bringing rain and strong winds to western areas by 1200. By the time we get to 1200 Tuesday the importance of the upstream ridging becomes more evident as we now have a high cell over eastern Greenland, promoted by the Aleutian and the east N. American ridges, with the elongated vortex trough running south of it and phasing with the trough associated with the main vortex lobe over northern Russia. The latter is the conduit for the very cold air from the Pole so the ingress of the Atlantic trough east is critical to the advection of this colder air into Europe and in particular in the direction of the UK. This is of course according to this morning's GFS as we are all aware last night's ecm had a different interpretation of this key area. As can be seen in this version the surface fronts have swept though on Tuesday leaving the UK in a complex area of low pressure and quite windy with temps just a little below average. It does not take a huge adjustment to the upper pattern to change this surface analysis.
  15. LOOKING AHEAD TO EASTER AND BEYOND After an exceptionally cold and snowy spell as we moved into March, followed by a brief return to similar conditions last weekend, many of us will be looking forward to some warmer spring weather or at least something more seasonal. Although a typical spring sees more frequent northerlies and easterlies than in any other season with a few colder spells, it also has some settled and warmer spells with an early taste of summer. We still have some time to see if there's a chance of the latter but the next few weeks seem set to provide further quite wintry weather. In this report I shall be focusing on the Easter holiday period in particular. My younger niece's wedding is on Saturday, March 31st and both families are hoping for some decent weather and have asked me what we can expect. Right now I'm not particularly optimistic. I'll examine the broader pattern and do one of my cross model analyses. I'll also look at potential upper and surface temperatures I'll finish with a more general look ahead to mid and late spring. I won't do one of my Arctic round ups (sea ice and temperature profiles) or my Eurasia round up (temperature and snow cover profiles) in this post but if I have time, I may cover them in another update early next week. . The Broader Pattern: I'll briefly go through the sequence of events that led up to the cold spells which I've covered in much more detail in earlier posts on here. In late January we saw a slight weakening in La Nina followed by a brief spike in atmospheric angular momentum (AAM) from mid January into early February with the usual time lags (of 10 to 14 days) leading to positive frictional torque and then positive mountain torque. This sent forcing "Rossby Waves" into the atmosphere which not only impacted on the jet stream but also on the lower stratosphere. Amongst other factors (still to be fully debated in the thorough post mortem which we shall see soon on both the strat thread and the teleconnections learning thread) this helped to trigger the very strong sudden stratospheric warming (SSW) during February. The SSW process itself was already underway but the final trigger for the impact is what I'm referring to (i go into much more detail on this in the final part of this post). This impacted on the surface with a full pattern reversal in the Arctic and HLB forcing much of the cold there down towards the middle latitudes. The combination of the slight weakening in La Nina with the positive AAM and the torques helped to produce a very high amplitude MJO (again the subject of debate) as it moved into the key phases 7, 8 and 1 (particularly phase 7 on this occasion) which also assisted with HLB. The strong Canadian PV which we had seen for much of the winter was weakened and displaced across the Arctic and towards Siberia. On this occasion the blocking pattern set up with a belt of high pressure (HP) from Siberia through Russia, Scandinavia and on to Greenland and towards north-east Canada. Exceptionally cold surface and upper air surged westwards from Siberia, through Europe, the UK and a long way across the Atlantic. The jet stream was forced way to the south, often tracking into the Mediterranean and even north Africa. The very strong long fetch easterly produced an unusually cold and snowy spell over the UK and Ireland in late February and early March. Then Storm Emma slowly moved in from the south creating blizzard conditions and then freezing rain in much of the far south followed by a thaw and milder conditions which slowly crept northwards. By this time, the weakening of La Nina had almost paused (temporarily - see the last part of this post), relative AAM and the torques went slightly negative and the MJO which barely entered phase 8, quickly lost amplitude and became relatively inactive (in the circle of death). The immediate impacts of the SSW weakened but still left its imprint on the lower atmosphere. We were left with a very odd pattern with the jet stream mostly continuing on a very southerly trajectory and a void between this and the HLB which became increasingly restricted to the very highest latitudes but the surface flow reversal was still evident to some extent. The void was filled for a while with further areas of slow moving low pressure systems (LPs). The strat specialists "had been" predicting a further (weaker) warming event which was likely to impact around or just after mid-March. The existing tropospheric signature from the initial SSW event meant that the surface layers were already primed for another and further cold blasts from the east (or the north) This produced another much briefer surge of exceptionally cold Siberian air which pushed rapidly across Europe and the UK. This time there was no additional assistance and also no interference (the opposite to earlier this winter) from AAM and the MJO both of which remained relatively benign. The SSW imprint has for a while become the more dominant driver. The second cold snap was very brief without that continuing (AAM/MJO) HLB support and we have entered another milder period. Please note that I have greatly oversimplified this explanation and a number of other factors were involved too - probably to at least some extent such as the east based QBO, record low Arctic sea ice build up this winter and the very weak solar influences (extremely low sun spot activity). I still have a lot to learn about the interaction of these drivers and will be fascinated by the ongoing debate into all the causes and relationships. I shall return to the "key" drivers shortly. Let's have a quick look at the current set up starting with the jet stream. I show the weekly changes for the last month: February 22nd March 1st March 8th March 15th March 22nd You can see that the main branch of the jet stream was mostly well to our south during the last four weeks with just occasional weaker more northerly streaks breaking off or looping around the UK. Right now, there is a slight break in the main pattern with the jet in the Atlantic taking a slightly more northerly route before meandering and buckling as it reaches the UK. Met O Fax 0600 Thurs Mar 22nd GFS 6z Pressure T+6 1200 Mar 22nd GFS 6z Pressure T+6 1200 Mar 22nd GFS 6z Pressure T+6 1200 Mar 22nd We are currently under an Atlantic flow with fairly weak LPs and frontal systems pushing into the UK during the next few days. The Azores HP is ridging slightly north-eastwards. There are also fairly weak LPs in the Arctic with a trough of LP extending from the north Russian side of the Arctic down into Scandinavia (this trough will be very important going further forward). There is a strong belt of HP over northern Canada and Alaska extending towards the North Pole. There is still a large pool of sub -16s to sub -24s 850 upper temps across almost all of the Arctic from northern Canada through to Siberia and Russia and a lobe of sub -8s to sub -12s remains across north-east Europe, northern Scandinavia and western Russia. There is a similar distribution of surface cold although values are not quite so low around north-eastern Europe and western Russia right now. Moving Into the Easter Weekend: During the next week to 10 days which takes us through to the Easter holiday period some slight but important changes for the UK are suggested in the broader pattern. Many of the key drivers will change very little. La Nina continues to weaken slightly, relative AAM and the torques are fairly neutral right now and the MJO is also pretty inactive. I will review all these drivers when I look beyond Easter and further ahead in the next section. I looked at the strat thread for the latest thinking and there is talk of an imminent "secondary warming" and/or a "final warming" (these may be the same event) and the demise of the strat PV. This change often (but not always) occurs during this time of the year and is the adjustment to the summer patterns and can occur at any time from later in February until well into April. It's uncertain how much "more" impact this secondary and/or final warming will have. The imprint from the initial SSW is still in the atmosphere. This is likely to be conducive to further bouts of cold being pushed towards Europe and the UK during the next few weeks. Just as I was writing this bit (currently around 1500) I noticed that @Blessed Weather posted on the strat thread. His last two excellent posts there as well as the very informative one from @ghoneym very much compliment what I have been saying. They are two of our "teleconnection team". I refer you to the page: https://www.netweather.tv/forum/topic/88772-stratosphere-temperature-watch-201718/?page=34&tab=comments#comment-3840387 There is a link there to a Met Office blog which has just been released today (Thursday) which is also very much on the same wavelength as my current thoughts. It's entitled "Will The Cold return?" I repeat the link here: https://blog.metoffice.gov.uk/2018/03/21/will-cold-conditions-return/ The comments there are rather oversimplified, nothing wrong with that but on this occasion it refers to the tropical forcing (which is the +veAAM/+veFT/+veMT and one of the triggers of the SSW "impact" (not the evolution of the SSW itself) that I've mentioned above (and pick up on in greater detail in the next part below). Adam Scaife says that this "is being exacerbated by the SSW" which is not quite right or at least somewhat misleading. There is reference to Judah Cohen's latest AER weekly report published on March 19th. I quoted Judah's reports a lot last winter and again in my last post on here about two weeks ago. Here's that link again now: https://www.aer.com/science-research/climate-weather/arctic-oscillation/ This is still very much in line with my current thoughts with a trough moving down from the Arctic in Scandinavia and more cold air being dragged in to Europe and the UK. I just quote one of his paragraphs in relation to our neck of the woods: ...."The PV is predicted to linger across Western Siberia over the next two weeks. This will contribute to persistent troughing/negative geopotential height anomalies across northern Eurasia including Europe. This will allow cold temperatures now stretching from Northern Asia to Europe and the United Kingdom (UK) to mostly remain in place with some fluctuation in intensity over the next two weeks".... Rather than a straight easterly, this time it'll be more from a northerly or north-easterly quarter. I'll now do one of my cross model analyses to see what the latest output looks like up to Good Friday and for Easter Saturday after that. Note that UKMO (to day 6) and Navgem (to day 7/8) do not go so far out. GFS 12z from 1900 Mar 22nd to 1300 Mar 30th GFS 12z for 1300 Mar 31st UKMO 12z for 1300 Mar 28th ECM 12z from 1900 Mar 22nd to 1300 Mar 30th ECM 12z for 1400 Mar 31st GEM 12z from 1900 Mar 22nd to 1400 Mar 31st GEM 12z for 1400 Mar 31st NAVGEM 12z from 1900 Mar 22nd to 0200 Mar 30th NAVGEM 12z for 1400 Mar 30th JMA12z from 1900 Mar 22nd to 1300 Mar 31st JMA12z for 1300 Mar 31st GEFS Control for 1400 Mar 31st GEFS Mean for 1400 Mar 31st There is now some pretty good consensus on the "broader" pattern amongst the 12z model output (JMA is from yesterday's 12z). They show HP moving down from the Arctic through and to the south of Greenland while a large trough of LP pushes down into Scandinavia and northern Europe. There are important minor variations in the finer detail in the position of the LP that is shown to be near the UK. Where available I've included the GIF chart to run through how we get from the current position to Easter Saturday. This shows the trajectory of the LP. One or more of the models show the following; dropping down just to our south-west; right over us; south or us or east of us. The timing will also be important. A little faster and a ridge of HP from the west might move in to dampen down any showery activity and produce more in the way of sunny intervals but still on the cold side. A little slower and we might be into a cold and showery pattern or even with more prolonged precipitation. It may well be cold enough for conditions to turn quite wintry once again. What is shown for Easter Saturday might end up coming through on Good Friday or somewhat later in the Easter weekend. The UKMO model only goes out to day 6 but we can judge their current thinking by the blog that I referred to above as well as their latest text forecasts which states: "The Easter weekend is too far away to be confident with any details. The most likely scenario currently is a spell of colder than average weather, with increased likelihood of overnight frosts, and a greater than normal chance of snow showers, especially in the north." They are right to state that the Easter weekend is still too far out to forecast the micro detail with any certainty. We may need to wait until we are less than 5 days out to home in on the precise position of the LP and even closer to the Easter weekend for the micro detail on how low temps might be and what type of (if any) precipitation we can expect over the UK. Well before I finish this post, the 18z output will have rolled out but as there are likely to be at least small changes from run to run, the cross selection of the 12z output is a good enough indicator at this stage. Let's have a look at predicted temperatures for Easter Saturday. This time I'll just take charts from GFS and ECM for the 850 upper temps and then GFS and GEM for the 2 m surface temps: 850 temps: GFS 12z from 1900 Mar 22nd to 1300 Mar 30th GFS 12z for 1300 Mar 31st ECM 12z from 1900 Mar 22nd to 1300 Mar 30th ECM 12z for 1400 Mar 31st . Both the GFS and ECM drop some sub -12c (to sub 20s) upper temps back into eastern Europe and Scandinavia during next week and towards Easter. The values for Easter itself are not quite so low with sub -2s to sub sub -8s moving into the UK on Easter Saturday. If that LP drifts a little further to the east into the near continent it's likely to drag in somewhat lower values. So the upper temps might also be on a bit of a knife edge in terms of rain or snow.. 2 m temps: GFS 12z from 1900 Mar 22nd to 1300 Mar 30th GFS 12z for 1300 Mar 31st ECM 12z from 1900 Mar 22nd to 1300 Mar 30th ECM 12z for 1400 Mar 31st Both the GFS and GEM (ECM 2 m surface charts of this type are not available) show that temps on Easter Saturday in the south may be around 8c to 12c in the afternoon. Not far to the north we see temps closer to 4c. It would only take a small shift southwards in the pattern to bring those much lower temps into southern and south-west England too. At 1400, these temps will be close to the maximums for the day. If it turns out to be a showery day, temps can fall sharply during the heavier showers. Until we can nail down greater detail nearer the time, it would be unwise to speculate further. I merely wanted to demonstrate the possibilities. if we are to see a flow more from a northerly or north-easterly direction then we need to take account of sea surface temperatures (SSTs) around the UK to see how much modification there might be: Sea Surface temps : March 21st 2018 February 21st 2018 March 21st 2017 SST Anomalies March 21st 2018 The first chart shows the current SSTs. Following the two exceptionally cold easterly spells, there are some very low values right now. The second chart shows the values a month ago just prior to the onset of the first cold spell. You can see that the temps in the North Sea fell by around 2c to 3c during this period and they have barely started to recover since the second cold snap finished during Monday. We should note that SSTs around our shores are usually at their lowest during March. This can vary from around as early as mid February (as in a few recent mild winters and early springs) to as late as early April (or even mid April following the long 2013 March/April exceptionally late cold spell). Much depends on the prevailing weather patterns, the temp of the lowest surface air layers and the strength and direction of the wind. Strong south-westerlies can quickly mix the top sea surface layers. Although these mid March SSTs are very low by recent standards, we have seen much lower values following previous severe winters. Back in the 1960s, Arctic sea ice extent was far greater than it is these days, often hugging the northern Iceland shores towards the end of winter. Following one of the most northerly months in the UK in February 1969, SSTs dropped from above average to well below. The north North Sea was still close to its average back then of around 4.5c (compared that to the 5c to 6c there right now, despite the recent cold spells). The SSTs in the Norwegian Sea were much lower and later on (into the spring melt) a few mini ice bergs were spotted off the northern Scotland shores and were a shipping hazard north of Shetland! The last chart (from the NetWeather suite) shows the current global SST anomalies (excluding the Arctic which I report on separately) compared to the 1971 to 2000 30 year mean. For the first time since March/April 2013, the SSTs surrounding most of the UK are below the mean. This is almost entirely due to the two exceptionally cold spells. Overall, the current low values will provide rather less modification than normal to an incoming air stream from a northerly (or easterly) quarter. Looking Beyond Easter: As there is still considerable uncertainty over the micro detail for the run up to the Easter holiday weekend, I will only look at the broader patterns and set up for this part of my report. There are a few indicators which I have not yet examined in any detail. Let's start with the El Nino Southern Oscillation (ENSO) state. The NOAA weekly reports are always useful to look at. Here's the link to their last report from March 19th: http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf I've snipped a few key pages from there and post them below (the last chart is directly from the NOAA website): NOAA expect the La Nina to weaken further with ENSO neutral conditions likely (a 55% probability so by no means certain) during mid to late spring and predicted to last throughout the remainder of 2018. After a steady weakening of La Nina during the second half of January and into February particularly from the lowest values in the eastern tropical Pacific, there was a pause in the warm up but this has resumed again in the last couple of weeks. Anomalies in "all four" Nino Pacific regions are now less than 1 c below the neutral level. The values are between -0.1c (in the west) and -0.7c (elsewhere) and not seen since last summer (compare the values to those in the fifth chart for previous 3 month periods in earlier years). There has been an upwelling of warmer sub surface currents in the central and eastern Pacific during the last few weeks. NOAA also refer to a weakening of the tropical easterlies and an "eastward propagating kelvin wave" . This is somewhat above my pay grade but I have just been consulting on this and it seems that this can be an early precursor to a change to El Nino conditions and one to look out for as the year progresses. The is an ongoing (smaller) risk of a return to stronger La Nina conditions and the next few months may be critical in deciding where we go from here. I will return to this towards the end of this post. Next up, the MJO. Again NOAA's weekly report makes for useful reading. Here's the link: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/mjoupdate.pdf ...and here's the summary + two charts from the NOAA site: NOAA Report Summary GEFS forecast from Mar 18th to Apr 1st GEFS forecast from Mar 22nd to Apr 5th ECM forecast from Mar 22nd to Apr 5th Well this is interesting. The NOAA report "was" forecasting a weak MJO remaining in the circle of death (COD). Today's forecasts bring it to life again. The GEFS plot takes it out of the COD into phase 6 during the next few days at increasing amplitude and then on into phase 7 at higher amplitude early next week and through Easter and then on to phase 8 during week 2. The ECM plot takes it on a similar path at the same times but at rather lower amplitude. This is a somewhat surprising turnaround and "may" be quite significant in favouring or assisting with further HLB patterns after Easter (more later). Now onto AAM and the torques. Here we have an excellent new source of data for the GWO (global wind oscillation) plots with an alternative to the GEFS output and also with the GEFS negative biases ironed out. I'll start with the excellent and new Victor Gensini free to view educational site - here's the link: http://atlas.niu.edu/gwo/ This site is still under construction with further developments planned including torque "forecasts" - something we have not had since the two NOAA scientists retired 2 year ago. Here are some of the current charts for March 22nd: Relative AAM By Latitude Relative AAM Anomaly By Latitude Global AAM Anomaly for last 90 days CFS Global Relative AAM 30 Day Forecast GEFS Global Relative AAM 30 Day Forecast CFS GWO Ensemble Mean 30 day Forecast GWO Annotated Phase Chart Looking at the third chart with the AAM anomaly for the last 90 days (these charts are available to go back over a full year) we can clearly see the spike from the low point mid January until the high point in early February that I referred to as the chain of events that helped to trigger the SSW (more after the torque charts). AAM is predicted to remain relatively neutral for the next month. The CFS ensemble members are mostly slightly negative whereas the GEFS members are mostly slightly positive but with no significant spikes for the time being. Frictional Torque (FT) Mountain Torque (MT) Global Calculated AAM Tendency Relative AAM Tendency Global AAM Anomaly Again you can see the spike in the torques which occurred during February. Quite a few people get confused by the timing and impacts of these processes, as did I until a few months ago. If you refer to the annotated GWO phase chart you can see that the process actually starts when AAM spikes from a negative or even a strongly negative position not just when it has gone positive. So in mid January AAM was shown as close to -3 with east Indian Ocean "maritime convection" or around GWO phase 3. Then the chain of events begins. As AAM rises into phase 4 (still negative) FT starts to rise. Then as AAM continues to rise it starts to become positive and moves towards the GWO phase 5 and this is when MT starts to rise. This chain of events has a usual time lag of around 10 to 14 days (in this case from just after mid January to very early in February). The different colour lines on the lower section of the MT chart represent the different torques (the key to these is immediately above that lower section). The black line represents the global torque which was strongly positive for a short while. With this phase of positive MT it was the EAMT (East Asian Mountain Torque) that was the main northern hemisphere influence. As this energy forcing circumvented the globe (known as Rossby Waves which impact on the jet stream causing it to meander) it interacted with the Himalaya mountain range. This sent up energy waves high into the atmosphere, through the troposphere and into the lower stratosphere. This involved a further time lag. Other factors in the strat were already initiating the earlier stages of the warming. Think of the MT energy waves as giving the process a violent nudge. Sometimes warming events do not propagate effectively down to the surface layers. The MT forcing was definitely one of the key contributory factors in triggering the final stages of the SSW and its impact on the surface. These processes and interactions are only beginning to be understood. AAM probably always plays its part in this process. It is not always EAMT that has the largest impact on the strat. Sometimes it is NAMT (North American Mountain Torque over the Rockies) but not on this occasion (it had been positive in January but was slightly negative during the key period in early February). There have been a few papers on the impacts of MTs on the strat in relation to earlier SSW events. The term is also known as "orographic forcing". As part of the post mortem and debate on the teleconnections learning thread into the causes, timing, triggering and impacts of the SSW, we intend to examine past MT forcing types and the links with previous SSW events. It will also be fascinating to see when previous potential SSWs came close but failed to reach the surface. I'm wondering if there was little or no AAM/FT/MT assistance in these years. This should also give us all a better idea of the degree of AAM influence and whether or not it must be an essential ingredient to the overall process. I am very grateful [email protected] for spending so much time during the last few months patiently taking me through the angular momentum learning curve. Whilst I still have much to learn, this has already enabled me to include some of this new found knowledge in my posts on the MOD and particularly on the Teleconnections Learning Thread. There are more detailed explanations of the AAM processes on that thread and I'll remind you of the link at the end of my post. To sum up this section so far, we may well be seeing La Nina move into an ENSO neutral phase. The MJO, which has been inactive for some time since early to mid February shortly before "Beast 1), is just starting to show signs of coming to life and in the key phases of 7, 8 (and perhaps onto 1) for assisting HLB. The SSW has left its imprint on the atmosphere and the secondary and/or final warming (I'll let the strat specialists agree or argue over that one) may help to extend the blocking and colder patterns for longer. AAM and the torques are forecast to be relative benign for the next few weeks. I would say that after the Easter holiday period the Scandinavian trough of LP may start to weaken as further HLB may replace it. This and other factors (partly discussed above) may either prolong the cold spell or allow for further cold bursts with brief milder interludes. Then what many of us want to know is will we see any decent spring weather? What I outlined above may well take us through to mid April. By then, assuming the trend continues, we may well see the demise of La Nina and an ENSO neutral phase. I'm still learning about AAM impacts through the summer half of the year but Tamara has already given me some of the lowdown. With AAM very quiet, the longer lasting impacts of the initial SSW are likely to have continuing impacts for the next few weeks and will still override other factors for some time. This would be in line with what I said above. What we need is something to jolt the tropospheric pattern. We do not know whether we'll see a final warming - it doesn't occur in every year. May be the Nina to neutral changes will help. May be the very recent suggestion of a more active MJO will help. Perhaps we'll see another spike in AAM during April. Quite often the Nina to neutral phase at this time of the year can produce some fine, dry and warm late spring and early summer weather. Positive AAM then will help to push the jet stream back onto a much more northerly track with LPs being driven well away from the UK. For this to happen we do need this jolt I mentioned above. If the broader pattern favoured further easterlies (rather than flows from a northerly quarter) then the continent does start to warm up rapidly during late March and into April. There is still a chance that the La Nina will strengthen again but this does seems fairly unlikely right now. So, although this might seem that I'm saying that all options are possible, what I've attempted to demonstrate are some of the signs to look out for going forward. Finally, I said last time that my MOD posts would be becoming far less frequent as I increasingly focus on developing the teleconnections learning thread. Our bolt on library should be set up soon. The fascinating SSW debate will be underway shortly after Easter and there will be a lot of other activity on there. So why not take a look through now and ensure that you come back to visit us soon. I'll post an update on here when the debate really gets underway. Here's the link: https://www.netweather.tv/forum/topic/89161-learning-about-teleconnection-science-and-background-signals/ or just click on the chart below:
  16. SE and East Anglia general weather discussion 03/03/2018 onwards

    There will be snow again - very late in March and/or during April.
  17. The Midlands Regional Weather Discussion 04/03/2018 Onwards

    Well it looks like my worries concerning April are been realised if the models are anything to go by. That is the fact I'll be away in Cyprus for a week from the 6th to 13th and it looks as though I could miss out on a epic cold spell for the time of year . I've got to go though as it's for my sister's wedding. Hopefully I still get to experience some of it before I go but been honest I was hoping that there would be one last hurrah at the end of March then a big warm up just before I go so as I wouldn't miss out on anything at home. Maybe it will still be cold when I get back but it will be about mid April by then so the chances of it been anything worthwhile will be less likely I'd imagine. Next week and into Easter still looks promising though so I'll just have to hope that period delivers still. Then again we're talking well into FI territory for the period I'm on about so who knows really. Sorry if this comes across as selfish it's just a bit frustrating that I won't be here and in a warm climate instead and if it is to be, good luck to all of you who'll be in the region and country to enjoy it. As I say I'll just have to hope for the best beforehand and also hope that next Winter delivers too. Not that its been bad at all mind so far this Winter/Spring as I've already had the early December snowy spell as well as 2 so far in late February/early March as well as last weekend, with still every chance late March/early April could also deliver before I go. I guess I'm just greedy about cold and snowy weather and I don't like the idea of missing out on any especially if it's in my back yard. But that's what living somewhere where these synoptic have been rare for a while does to you, if you really like them as I do. Sorry to ramble just wish I could look forward to the potential properly without worrying if I'll even be at home to enjoy it.
  18. Yeah. Well hopefully the GFS changes for the better, if not we can only conclude there is no snow god afterall, that or you lied about doing the snow dance.Maybe you did it, but forgot to put the bra on your head, did you? Be honest. hehe.
  19. Anything to get out of Easter snow predictions.😁❄️
  20. Cloudy with light to moderate rain Temp 5.7c
  21. Yesterday
  22. F1 2018 season

    Anyone else staying up to watch the first practice session of the season?
  23. I've said it before but I always find August is very much a 'meh' month these days that alters the overall theme of many summers. If it's been a good summer in June and July, August and its mediocrity come along and lower the tone e.g. last year. That said, if it's been poor, August raises the tone e.g. 1998 or 2007. I actually thought August was the best summer month of 2016.
  24. Net Weather Gardening Thread

    Now that winter has ended i have planted my tomatoes, beans, carrots, corn, courgettes, onions and cucumbers out in the garden, expecting a hot sunny April so they should be thriving come May.
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