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Showing content with the highest reputation on 27/12/16 in all areas

  1. Sorry - apparently it was copied to a Facebook group without permission. We had this issue a year or two ago. Thus removed to prevent further reproduction with risk of changed context.
    53 points
  2. Indeed Nick. With a strong signal for -ve U wind anomaly developing through the Equatorial Pacifc in the next few days, it's not so hard to see where this is coming from. That's centred on 120w which gives a strong projection to a MJO phase 8/1, regardless of what the wheeler Hendon plots show right now. GFS also suggesting a net easterly U wind anomaly through 20N and 30N across the Eastern Hemisphere at the end of the month giving a classical Nina look the atmosphere. That should engender a low AAM base state, weak amplitude GWO phase 2, which favours ridging to the North-east Atlantic. Interestingly should also set up a strong +ve frictional torque, and precursor to amplification later on in the month. With the configuration of SSTAs in the west Pacific and Indian Ocean still favouring convective anomalies over the Maritime Continent, would expect to see downstream wave breaking favour a low frequency patter of themain lobe of the polar vortex displaced slightly west and south of Greenland which suggests we might need to correct that ridge position further east over time. So whatever transpires wrt ridging to our NW and north over the day 7-10 timeframe (and reload over the northerly really well advertised in eps tonight, as essentially it has been the case for several days now), my eyes drawn to the north-east in the extended. Back that up with a cold, often anti cyclonic period in the medium term, you start to build a case for a below / well below monthly outlook. < Alistair - perfect timing!
    45 points
  3. Looking through the extended eps - wow! basically sceuro trough and griceland ridge. The Azores trough then spreads east to join with the sceuro to bring the 'holy grail' of southerly jet flat across the Atlantic under the high anomoly into the broad euro low anomoly. I don't expect to see a better mean anomoly run for coldies. as Matt tweeted, need to see some consistency on it but it isn't a flip from previous output.
    39 points
  4. This thread will read a lot better if a few of you stopped bickering over each other's pov.It's just spoiling the thread for the majority-pm each other if you wish to continue down that road. By all means have different views on the outputs but keep them polite and if possible use charts etc to back up what is said. Now then back to on topic posts please- just discuss what's in the outputs. Thanks all.
    36 points
  5. Come on TEITS, the only time this theory is trotted out is when there is no sign of cold weather. So yes it is fairly often with our run of relatively mild spells around Christmas. Odd though, don't you think, that this theory is absent if 'cold' seems likely and even less so if it is cold and some get snow over Christmas. Like a hundred and one other factors taken into account by forecasters the period of data absent, for whatever reason, is ALWAYS factored in to any professional forecaster when assessing all the data available. In truth there is a larger number of aircraft over the Atlantic on Christmas Day in the past few years than say 10 years ago. Have a look at the IATA data for these days if you do not believe me. Also a bit rude of you to suggest for a professional to go back to basics. Can you tell us what your meteorological qualifications are please? Sorry for this post not having any model data in it but as an ex forecaster this red herring every year when it is not cold gets on my nerves.
    36 points
  6. Exactly. Nearly every run I have seen over the past few days has shown snow for some if not ALL of the UK. People need to get a grip of reality. In my little part of the world, I haven't seen snow for 4 years. The models are showing at least a decent chance. "Oh it's just a northerly toppler" so what? When was the last time we had one? If it just lasts one day, thats one day in 4 years my kids have had the chance to even throw a snowball!! Bring it on!
    34 points
  7. Dunno what the panic is about it looks plenty of reloads will be on the cards. Either way the weather is going to be a lot interesting then it has been.
    29 points
  8. Let's have a look at the last three GFS 00zs for this coming Tuesday (03 January) at 00:00 (i.e. late Monday into Tuesday): So left to right that's: 1. Today's GFS 00z at T+174, 2. Boxing day GFS 00z at T+198 3. Christmas day GFS 00z at T+222 Not sure where the inconsistency/downgrades are?
    28 points
  9. The licensing agreement with UKMO, negotiated a few years ago, is for sharing selected items that help offer technical context to forecasts, but social media growth means a risk of items disseminated without permission or proper context and thus possibly not in spirit of original forecast thinking. For now, I'm afraid that means no further sharing of that material aside from more limited ones through twitter, given sensitivities. Back to model discussion.
    25 points
  10. Most of the EC 00z ensembles keep the cold theme going right to the end, with the mean generally 2c or so below normal. The graph follows a very similar theme to the GEFS.
    25 points
  11. Everyone will sleep well tonight knowing that the the highly respected CFS is forecasting the mother of all easterlys and -16c upper 850s over central England.
    24 points
  12. German met man is warning of a siberian whip effect could well about to lash in western Europe i quote Jung writes: As the chart above shows, very cold air flows in to us here in Germany from high up. That would put us somewhat below freezing also in the daytime in many regions. This scenario has been popping up in the weather model calculations for a few days, and so we should take it very seriously.” - See more at: http://notrickszone.com/2016/12/27/meteorologists-warn-of-possible-arctic-blast-for-europe-also-threat-of-green-energy-refugees/#sthash.sQPkuqjG.L1E5oqnx.dpuf
    24 points
  13. The anomaly charts have shown a cold (not just surface) spell from the end of the year for 7-10 days for the last 3 days. latest links below http://www.cpc.noaa.gov/products/predictions/610day/500mb.php with ECMWF-GFS rather less so http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html NAEFS also along the same lines http://www.meteociel.fr/modeles/naefs_cartes.php?code=0&ech=240&mode=0&map=1&runpara= Detail of any snowfall will only show up on the synoptic models and there will as always be variations between them right down to T+24h, maybe an even shorter time scale.
    23 points
  14. The weather industry does not stop because it's Christmas. The lack of data (which amounts to a small amount of aircraft data) being put into the models over Christmas has a negligible effect, and there have been studies into it. This needs putting as a header into this thread every Christmas.
    22 points
  15. This forum always seems to read; it's on, it's off, it's on, it's off again in the hunt for Synoptics the vast majority want in here, cold. The clue is in the timescales involved, as to whether people perceive an individual run to be a BOOM run or an epic FAIL. For crying out loud, oops. Cold air (Maxes 2-3c below average) has arrived, thick fog and frost are set to persist during daylight hours over the next 2-3 days for an unlucky (lucky?) few. Post next weekend, ever colder air (Maxes and Minimums several degrees below average) could bring some wintriness to some parts. The New Year period itself may NOT be in the bag yet, but with a mid-Atlantic blocking high positioned due NW/NNW of our shores, an albeit brief Northerly/Northeasterly flow is a decent outside possibility at such a range. In fact, they are dream-like winter wonderland charts given what we could have at D5/D6.Whether the Northerly/NE'rly flow lasts or not who knows, but the New Year period albeit temporarily milder, to begin with, will highly likely kick off 2017 on a HAPPY note for coldies, with wintry weather patterns never far away. More than enough reasons to be cheerful! Just don't go rocking the boat before it's even left the port, my friends.
    21 points
  16. Wrong thread Feb.... moaning thread is the one you want
    21 points
  17. Another post showing the problems of comparing different runs. Stick to comparisons of the same time down to 144h. Also compare one model with the other for the same time, ie: 00 or 12Z, and until the time scale is below 144h don't complicate matters with the 06 and 18Z. Honest it does work, probably 70-75 % of the time and also ensures less stress for those searching for cold and snow. But if you enjoy the roller coaster just ignore me.
    21 points
  18. I often enjoy reading your posts TEITS, but seriously, the bit in bold above is doing you no favours at all. In fact toys starting to be scattered about by many, far and wide from the pram today, as the realisation dawns we aren't going to have a repeat of 1963. Shock horror surprise. Anyway, it all looks full steam ahead for a great month of great potential. That's all we can ask for at that stage. The window of opportunity remains, downgrades and upgrades wil happen but until a full on Atlantic zonal train is upon us and in all the chart outputs to boot, let's enjoy the moment. Nothing has or hadn't occurred yet for goodness sake.
    20 points
  19. So in the semi reliable time frame we have freezing fog,frost,possibility of back edge Snow followed by snow showers for some and some folk are unhappy I suppose why some folk are unhappy is the fact we don't have -15 uppers and a Screaming NE wind and whiteout conditions. C.S
    19 points
  20. Considering recent January's have been pretty crap to say the least. I'm quite happy with where the models sit right now. The big 3 at 120 look ok to me, at least we are in the game for cold & snow rather than in a hopeless zonal onslaught. Plenty of scope for upgrades surely...
    19 points
  21. As long as we keep seeing bouts of amplification upstream (aided partially by huge Pacific ridge), we have a decent enough chance of getting enough ridging towards Greenland I have the distinct feeling it's a matter of when rather than if.
    19 points
  22. Here's UKMO on the left and ARPEGE on the right. The latter has a slight negative tilt to the Canadian trough while UKMO has a neutral - direct north - orientation. Around 24 hours later, this slight difference grows exponentially, with dramatic results: While UKMO is progressing to a surprisingly quick dive down of a shortwave low from the northwest - with nice separation from the Canadian/NW Atlantic trough it has to be said - the ARPEGE solution sees an omega block established to the west which is going nowhere fast. The UK is in an increasingly unstable northerly as the jet angles NE to SW on the east flank of the OB. A rare and valuable setup and nice to see that the option remains on the table, especially coming from a high-resolution model, albeit not a particularly reliable one at such range.
    19 points
  23. You appear to be concentrating solely on one output and not considering the overall bigger picture that lots of people have been telling us about. I think there's an awful lot to be positive about.
    18 points
  24. The GFS continues to show a very cold weekend with Northerly winds bringing -10/11/12 uppers over a large swathe of the UK with snow showers pushing South. It will certainly feel bitter than of late, In-fact it will feel like Winter..
    18 points
  25. Well - I dunno. I've done a lot of surfing and reading today, and I have to say the signals for upcoming cold and long term cold are not strong. However we have some positives that I'll highlight here. Firstly the vortex profile shows a moderate wave 1 event over the north pacific - pushing the vortex towards Russia. I wouldnt say that this is a particularly violent movement, nor is it really kicking the vortex off its perch... but it will provide a degree of support to height rises to our NW and possibly to the movement of cold air westwards out of Russia. The ridge is noticeable from 10hpa down to 100hpa with signs at 240 hours of the mid atlantic ridge to the west of the UK. The MJO heading towards phase 2 produces a composite suggesting heights to the NE - though not directly supportive of low heights to the south which is really what we need. However - get the heights to the NE and perhaps we can still get that pull of cold. Note this is a very averaged chart over many years and many amplitudes of MJO - so only a very general guide at best. And the last bit of interesting info is in regard to the PNA flagged by IanF earlier today. The PNA is forecast to go negative for what appears to be a sustained period: ftp://ftp.cdc.noaa.gov/Public/gbates/reforecast2/teleconn/4indices.png Trawling through the PNA archives revealed one interesting correlation. If we accept that Jan 79 and Jan 63 were the two coldest and snowiest Januarys overall in recent decades then guess what? Both had a sustained spell of -PNA. In both 1979 and 1963 the PNA was negative for 25 days in January. 1st Jan 79 (blizzards and the all time Cornish minimum record of -16.... cold enough even to freeze Sidney's nuts) and 13 Jan 79 (coldest recorded daytime maximum in the UK in the 1970s) were both famous days in UK weatherlore - note the prominence of the pacific ridge on both dates: And how about the start of the most severe week of the most severe winter on modern times - 17th Jan 1963? Take a look - you get the picture. Perhaps the -PNA comment from the Met might be a key factor going forwards...
    18 points
  26. Flippin' eck - Stewart's just posted in a significantly more knowledgeable tone... but pretty much said the same gist. As an avid learner and perhaps "semi semi" knowledgeable reader on these things that's a big boost in every sense of the word boost. Perhaps we really can get that push to cold!
    17 points
  27. Let's see if a bit of teleconnective analysis can help here as I seem to have lost my tea leaves.... Ventrice's site now pointing quite clearly to a phase 8/1 progression of the MJO from around 192 hours out. Amplification uncertain, but phase 8 composites look thus. Note that last night I posted composites based on the model consensus to move us into phase 2... but let's for a moment go with Ventrice's interpretation as a much respected seer of pacific forcings: This would lend weight to the idea of a greenland ridge and scope here for the ridge to extend to Scandy. Low pressure underneath. Looks rather tasty. Progression into phase 1 with composite thus: Ridge transfers to Scandy while pressure falls over Europe. Tasty once again. Phase 1 does not teleconnect to a strongly -EPO and yet a strongly negative EPO now forecast over on NOAA to last until at least 10th Jan - and a look at the bar graph would suggest a bit beyond that barring a very sudden reversal. I assume NOAA use GFS.... ftp://ftp.cdc.noaa.gov/Public/gbates/reforecast2/teleconn/4indices.png Putting 2 and 2 together I'd say therefore phase 8 perhaps to hold on until around mid month if the modelled teleconnections are anything close to accurate. With luck by this stage we would have cold air embedded from Russia as atlantic systems start to drop south and hammer along the channel. One model - JMA - has now shifted to an 8/1 forecast resisting any move to phase 2... So chances of MJO assistance increasing? I dont have access to GWO composites - cant find them no matter how hard I try. Anyone got them? Anyway Stewart posted the GWO phase 2 composite for January a while back... and the GWO forecast from GEFS is staunchly standing by a phase 2 progression as it has done now for over 5 consecutive forecasts: Stealing Stewart's composite graph from his post way back reminds us of this: A good degree of support here between the GWO phase 2 composite and the MJO 8/1 progression. Wave 1 warming is up another notch on yesterday - part of the predicted forcing of the vortex away from Greenland and over to Russia. So.... while I remain a bit sceptical of the required amplification to sustain these signals it cant be denied that there is support for an exciting 2 - 3 week period coming up. Please note that the above paints - I think - the most positive spin on the current global situation. I would be much happier if there were signs of greater amplitude - but with the neutral level of the current signals (apologies - I know this has been said over and over... but the fact remains that the signals really arent strong as of yet....) maybe we can get sufficient forcing to tweak the north atlantic pattern bearing in mind the vortex is losing strength again (as pointed out by Steve) and the ENSO base state is trending neutral also. The smallest of teleconnective "puffs" maybe all we need! The other possibility - and a significant possibility - would be that lack of amplification as a result of the atmospheric Nina state now adopted, and a fairly quiet MJO to boot, would lead to a pulsing mid atlantic high, but one constantly flattened and overidden by the jet. Net result - bog standard NW flow for the north and fairly benign nothingness for the south. Here's hoping we can avoid this.
    17 points
  28. I can understand the gloom given the very underwhelming December. Many of us (especially myself) were chasing day 10 charts that were constantly being pushed back. We aren't seeing that now. The screenshot below is from the meteoearth app. I believe it uses ECM data. It is quite useful for me as it only goes out to 5 day preventing too much excitement over charts too far into the future to be reliable. The brilliant charts we had earlier on in the season never got into the 5 day timeframe. The screenshot below shows,by a country mile, the best chart of the winter so far, very encouraging as we head into January. We had an extremely blocked autumn. It's typical in December for the jet stream to be very active, now as we head into January hopefully we will see blocked conditions take over once more, this time with a much larger cold pool to tap into ...
    17 points
  29. "there have been studies into it" I'll also add that myself and several others on here actually work as forecasters, and this "lack of data" myth has zero bearing on our thoughts. In fact, I haven't heard it mentioned once in my office. It's only something that seems to have manifested itself through hearsay on forums and social media. If a butterfly flaps its wings in China, you get Chinese whispers.
    17 points
  30. Instead of clinging to some kind of conspiracy argument regarding data acquisition please can you explain why you think we are set for a potentially severe shot in week 2 of January. Far more interesting than a pointless debate on the workings of Christmas Day.
    16 points
  31. Gfs18z looking like a much cleaner reload for cold. This at day 6.
    15 points
  32. To put the radiosonde myth to bed... http://weather.uwyo.edu/upperair/sounding.html Check out the archives, soundings are still made on Christmas Day. And let's be honest, in the grand scheme of things, radiosonde data is TINY in comparison to the world. I fully expect this nonsense to be brought up again next Christmas, and the next, and the next. That's the last I'll say on this matter.
    15 points
  33. Such a shame that happened again Ian as I and everyone else on here really appreciate all your contributions( even if I don't always fully understand what you say ).
    15 points
  34. On a more positive note the day 10 ECM has the same vertical advection profile over western greenland as Nov 2010- see here ECM 12z V 2010 One to watch for Greenland blockinh- So 'some' excitment this week although nothing extreme- with most hoping for a more substantial reload ....
    14 points
  35. Nice , but like Matt says, consistency now needed!! And A pinch of salt
    14 points
  36. I'm going to add 'optimism' to the table. As some folks are looking for the breakdown of cold before it has started. (although -4c here this morning) A month ago we would be delighted if -5c 850 was within 50 miles of Shetland The GFS 6z has largely sub -5c from 1/1 to 11/1 and yes I now about 2m temps We have had real cold and faux cold this winter, the car didnt give a s*** what type of cold. Will we get real cold v no blocking signals so break down at T240 means it doesn't count. Supporting charts from GFS 06z 1 January 2017 2 January 2017 11 January 2017 31 January 2017
    14 points
  37. Absolutely no more post on Ian's copyright issues via Meto, Please use PM funtion for any more questions on the issue. Thanks please continue.
    14 points
  38. I've been following netweather for many a year, haven't posted on here in years but Fergie's post was the most wintriest update I've seen him post in a while. And I just want to say I love reading this thread every winter, keep it up guys.
    14 points
  39. I hope no-one minds me saying so as an ordinary member, but a theme I have been putting forward for some time now (circa 4 weeks) and gets construed at times as "glass half empty" As stated and reasoned last night, and several times previously, downstream amplification is not assured in terms of being sustained if there is not the latent supply in the atmospheric circulation to ensure it so. My own eyes continue to be on the GSDM (tropical and extra tropical budgets) and how they are best interpreted with the troposphere/stratosphere relationship - and it is from there that I attempt appraisal of the NWP
    14 points
  40. What is apparent is that there is a strong signal for Pacific forcing from around D5 right out to D15 on the GFS. This helps promote the omnipresent Azores/Atlantic ridge of this winter; ergo ideal conditions to build pressure north in the Atlantic quadrant. The problem is that the PV remains mobile, shifting sands of lower heights pushing around the NH high latitudes. It looks like this rather than a down tick in the two wave forcing is causing both waves to lose their sharpness and flatten out as chunks of vortex pass north of them. We keep seeing false dawns, where the models interpret the forcing to split the vortex enough to create a true blocked NH pattern. With little apparent help from strat, top down forcing we are relying on the trop to over power the PV. The London ens remain below the seasonal average from Sunday till D16 though the op and control remain progressive compared to their members for temporary milder interludes of uppers: A model nightmare charting the interaction of PV -v- Heights, as we have seen from past model watching, so we can be led up the garden path in such scenarios re optimum winter synoptic's when they show up. Certainly a downgrade in the medium term for those (op), but it remains a cold outlook and so surprises could pop up, and we won't have the lag time if the pattern becomes more conducive to a snowy pattern down the line.
    13 points
  41. I've certainly seen worse Day 10 ECM means than this!
    12 points
  42. With both my UK and Alps 'snow search' hat on I've been looking at the GEFS NH 500 Mean Anomalies since yesterday morning's 0z run. There's a consistent story for the 1st Jan, with strong heights to our west and low heights to our east. So we now have reasonable continuity with GFS Op runs showing a northerly flow with UK snow for (at least) higher ground in the UK. The bad news for the Alps is the continued lack of lower heights in Europe is reflected by Op runs continuing to show the band of snow rapidly fizzling out as it approaches the Alps. Charts for 0z yesterday, 0z today and 6z today for 1st Jan: Moving on to the 5th Jan and looking at the same run of charts they show a minor but unwelcome trend (if it's snow you seek), with the heights to our west starting to extend across the UK into Europe. Similarly the lower heights over Scandanavia are edging further east. This suggests we may end up more under the influence of high pressure with any 'bite two' northerly flow slipping away to our east? We'll have to await this afternoon/evening's runs to see whether this is a continuing trend or not.
    12 points
  43. Looking ok for a spell of below average temps. One gets the feeling though that it won't be a full on arctic outbreak (not yet) but more of a series of swipes..... but potent swipes. The Euro heights do bother me a touch on determining the cleanliness of the first cold thrust, enough room there to water the first swipe down. I've got lower stratos warming pencilled in for early NY which if comes about a lag for mid Jan prolonged arctic outbreak. Outlook anyway for Jan seems to be 'warming' (pardon the pun) up nicely and with consistency of JH method a good coldie start looks on the cards Just seen that laymen sunspot count i.e. Same as when used to read sunspots in Maunder and Dalton minimas...shows we have had 17 spotless days. This cycle 24 is plunging rapidly now and is below cycle 5, it could get interesting this. Siberia locked into freezer with record cold for Western Siberia. BFTP
    12 points
  44. I think that's because the models are hunting for the right solution and what, to us, may appear to be a massive (inter-run) swing is, in the general scheme of things, no big deal? Apart from that, I think it's fairly safe to say that a pattern-change is underway...
    12 points
  45. We shall see how it unfolds. ECMWF Monthly also raises +ve MSLP/GPH anomaly to NW (S of Greenland) into week 2; interestingly it supports GloSea5 on broad idea of a colder than average spell much/most of Jan, with varying NW/N/NE flow (perhaps E'ly later in month); even by week 4 with unusually prominent -ve temp anomalies for southern UK (given the lead time). One way or another, model output looks an awful lot more interesting versus this time a week ago.
    12 points
  46. Couple observations gfsp again looks west based -NAO but this run gets it far enough east. Would be ironic if the initial bite at the cherry ends up too far to our east whilst the second one heads west! talking of which, the ens have always been keener on nite two being more successful. Now just about reaching day 10 so we will get to see how ECM op deals with it as it should offer more insight with its higher resolution (though note it is also liable to over amplification for probably the same reasons). The eps this morning lowering those euro heights post day 10 more convincingly than yesterday though coldies should be concerned about the potential for ridging hangback from the Atlantic to our south. The spread on the ECM ens post day 6 are pretty masssive and indicate that the route to the second bite may well not be too obvious - I wouldn't necessarily write off a surprise on what seems to be the current direction of travel days 6/10. Continues to be fascinating !
    11 points
  47. Morning all. This forecast chart from UKMO for NY Eve shows how the timing and clearance of the advancing cold front could be a problem on NY Day , especially over Southern England. Clearly there is a thought of a wave formation working up from north of the Azores along the cold front. This can have two effects in the forecast : a) timing of clearance with possible delay b) amount and type of precipitation, thinking of rain turning to snow as colder air under cuts . Obviously these charts can be dropped or change the expected synoptics for the period but looking at the strength of the Euro high its fairly likely of some sort of delay in clearance. Meanwhile ECM reverts back to a colder set up again. Not sure where the UKMO is going after 168t, maybe toppler set up with further chances of renewed Arctic attacks as we go into later forecast period as indicated along the lines of GFS. C
    11 points
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