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  1. 122 points
    My retired colleague Ian McCaskill, RIP, would have relished discussing this Christmas Kerfuffle on-air with typical humour. GFS 12z deterministic very similar in final reaches of run to Thursdays ECMWF Monthly broadscale set-up for same period just after Christmas. Whether that will remain so tonight, we shall see....
  2. 121 points
    An ode to the model output thread... "In days of old, when Thatcher was bold and Kettley was a weatherman, Tales are told of winters cold, and snow lay everywhere, man. The World Wide Web and ECM were yet to be invented And weather forecasts at the time were often quite demented! But there's no doubt, the records show, that winters then were colder And five foot drifts were commonplace - they came up to your shoulder! For years and years all we've had is windy wet and mild And although it's not all been bad we crave a winter wild.... Now... The models hint that Scandinavia could maintain a block To curb Atlantics bad behaviour - that would really rock! But... The GEM can't be trusted; the GFS is dire The ECM has often busted; the CFS? - a liar! So on UKMO we must rely but wait - is it cursed? More runs needed, standing by.... let's get the cold in first! Hope you all have a great weekend of model watching!
  3. 114 points
    Early guidance forewarning of next weeks weather was issued earlier on, and this has been further enhanced with extended outlooks in bulletins. AFAIK (comms not being my area) public agencies and major private infrastructure will begin a daily briefing cycle as of tomorrow. To revisit previous post, latest MR output (MOG) resolving to further mute ‘breakdown’ scenario; with continental blocking signal reinforcing through well into March. Atlantic incursions are expected with southerly deflection; considerable potential for extensive and disruptive snowfall as these air masses interact. Short term, ECM:UKMO evolution favoured and considered likeliest; corresponds well with other products and illustrates fair consistency. Small ramp. Next week = mega. SB
  4. 114 points
    Evening All Ice Cold hope your still with us .... So the much touted SSW is coming into view & here’s my thoughts + timelines of when / where to expect it... We have seen lots of posts & comments on it - but whats the reality likely to be -??? The Omni present warming in the GFS charts is usually due to the model & its poorer vertical resolution V the ECM, as a result there is an over reaction / over estimation of how much a warming is going to impact the zonal wind @10MB - so because of this 'bias' when viewing the mid / long term outputs churned out by the GFS we have to be a little on the sceptical side as these are normally moderated & scaled down even wiped out ! However we have now seen the evidence in the Berlin site that a downwelling SSW event will make it to the 10MB level & indeed go on to challenge the date record for the time lf year- ( this is NOT the same as the usual deceleration of the zonal wind we see at this time of year as that is more of a gentle reduction all the way to mid april when the vortex breaks its annual westerly influence ) So as highlighted we have passed the point of no return in the stratospheric modelling where a SSW is now just 5 days away for the 12th Feb *** Take note of this date -- The plots below show steep downward curve of a signature warming Note the main black line being Climo - but the ensemble mean from the GFS running out at mid -20 to -30 M/S... The clustering is quite close - further backed up by the another illustration of the ensembles from the hannah attard site With the mean bottoming out at -32M/S *The date record for this time is ~ -17 M/S & the all time record low ( using Merra data ) is -35 M/S The ECM berlin forecast below is not as bullish as the GFS coming out around -17 M/S @10MB but none the less still classed as significant event... So what we have in modelling terms of a SSW due is * The first one in 9 years ( I dont think last year was classed without checking ) * Possible record breaking reversal of tge zonal wind... If your thinking whats best in terms of impacting the UK its simple- The lower the negative number the better... - record breaker ? yeah I will take that please... Why?... The bigger the negative number the stronger the easterly flow is across the mid lattitudes. !! ( think feb 63 / jan 85 & so on ) Whats the models churning out then? The SSWs are classed as 2 types - Wave 1 displaced vortex or - Wave 2 Split Vortex .. This is whats expected - A classic wave 2 Split vortex- with 2 clear areas of poleward flux - over the far East & canada- Now luckily for me the historic SSWs have already been classified -we are looking for la nina years / W2 / split vortex- 6 years appear as matches - 28 Jan 1963 - 7 Jan 1968 - 18 Jan 1971 - 1 Jan 1985 - 21 Feb 1989 - 24 Jan 2009 Below are the 10MB increase in temps at the time when the zonal wind hits 0M/S Obviously they all have 1 thing in common- The huge rise in temps across the pole - Now the Date of the zonal Mean hitting 0M/S isnt the day of peak blocking - Looking at the dates above peak blocking appeared 7 - 11 days post Reversal - see below day 11 charts from the above warmings ( 500 MB anomaly ) Whats apparent is HLB is quite prevelent & most are centered ( for us ) around greenland & Western Scandi - Also all 6 Splits have varying levels of troughing to the south - but all have an anomaly- So that really leaves with a level of expectation that should at least give us some confidence for Feb over the following dates- 12 Febuary : is 'R' Day- as in the reversal of the 10MB zonal wind where the eastward progessional component is replaced by a westward one 13/14 Febuary : is peak 'R' days where we will know the magnitude of the warming & just how much westward ( reversal ) component there is - Sub -20 M/S is the date records & anything below is the jackpot - 16-18 Febuary - Mid to high lattitude transitioning - This is where depending on how lucky we are for our area we will see MLBs start migrating North to the pole as zonal wind lag filters through the lower layers of the atmosphere & support builds for HLB - look for the 3 key wave patterns ( atlantic / Scandi & pacific (-EPO) The UK can get very cold in this period if the migrating highs are favourably positioned from the outset.... 20-24 Feb - Peak HLB blocking across the NH - peak -AO signature & peak cold overall for the mid lattitudes ... *** IF the GFS lands with the depth of negativity then Late Feb early march will be on a par with 2013 for AO negativity & possible / probable UK cold / snow.... if the negativity is watered down then the cold signature will be watered down & less dominent in western Europe... Best S
  5. 113 points
    Come on those looking for the breadown before the major cold and snow has begun You will be very lucky if that is the correct word to see this in ANY winter in the rest of your lives I would suggest, let alone the end of official winter into the first week of spring. I worked through 1962-63 and was 8 years old in 1947, so having looked at GFS output over the last several days and UK Met along with ECMWF I am close to being gobsmacked at how the deep cold has been correctly forecast on the models from 2 weeks out. Equally congratulations to those of you who understanding the SSW and other connections far more than me were predicting cold even further back. Looking at the 12z GFS, not too different to other runs over the past -3 days for my small area, and it predicts 2 ice days, snow on 3 or 4 days with possible depths greater than anything here since 30 November into 1 December 2010. As a long since dead football commentator was fond of saying, 'quite remarkable'. I am now going to see if I can discover, during the 1962-63 coldest spells if the history is available to show what 850 mb temperatures were. I know what the surface temperature were, and have several times posted that when folk reminisce about past winters. Enjoy but please do remember to try and support anyone living near you that may need this, this is a going to be a pretty severe test for a lot of folk, even if their heating is up to it and they can afford it.
  6. 112 points
    So a rather long post ( Will also clip into the winter forecast thread ) However just an update on saturdays post, a large debate around models - & I took the day 6 UKMO & GFS charts to compare for verification- These were both of the 6 dayers GFS on the left. Note GFS flat with no heights in Greenland, UKMO more amplified with heights - Also a circular vortex North of Scandi. UKMO has energy seperation & a closed low - GFS just sends a 'block' of energy through - Look at todays UKMO 72- Comments: -Circular vortex just North of Scandi -Closed low traversing East towards Iceland - Residual heights over Southern Greenland - Arctic High 1040MB. Conclusion UKMO is a clear resounding winner here- every element that differentiated from the GFS is still apparent in the T72 chart, this is a big thumbs up for the UKMO, proof ( on this occasion ) that the GFS clearly has an eastward bias & why looking at developing heights over the pole ( NB UKMO 144 today ) The UKMO resolves energy better... So, onto the SSW it seems an eternity since the first warming started showing up way back in December - but now we are day +6 since the wind reversal- Much of the discussion has been about the 'slow' response in terms of downwelling in terms of creating a significant AO - This is depicted nicely on the NAM index which I have saved from the other week- The GFS bias initially showed minimal downwelling, however gradually ( like the comparison with the UKMO above ) has slowly come into line with a more 'propergating' feature. I think we have been unlucky with the QTR - sadly the NOAA composites page isnt available, however twice there has been significant mid lattitude blocking developing in the locale forecast as a QTR relating to the strat split- However the blocking has been just to far East for us to really gain any benefit - *but* as far as Europe as a whole is concerned in terms of snow this winter could challenge the record books in terms of sustained depth from mid Jan onwards- My memory ( from the old teletext days ) was that St Anton could reach 600CM on the tops by the end of Winter- By the end of this week it will be North of 400CM Also records going in Greece with snow in Athens & -23c reported North of the region- So whilst the QTR missed us that release of deep cold didnt miss everyone... The next stage of this SSW / Split will be crucial for winter as the norm here would be a gentle recovery from the PV ( not to normal strength ) - however if like me you were hoping for something that lasts longer than a few days - IE 1 MONTH then a secondary warming & further splits would be the upper cut to the PV that would knock it out for the rest of the Winter. However just before commenting on that lets see the progression of the downwelling- The charts at the top are from around NYear- now look at the NAM index from the GFS today ( remember its still not the best model for coupling the Strat > Trop ) Here is the NY 100HPA profile V todays Lots more clustering below 5M/S- some below zero. This is why we are seeing the GEFS respond post 192 - Note the AO Ensembles - Starting to gain momentum towards -4. Moving through day 9 on the ECM strat from yesterday we see that the Uwind is still negative but importantly the allignment of the vortex lobes are significantly different to this week - encouraging blocking- Red is the left lobe allignment Blue is the right lobe allignment Yellow is the blocking potential- Its quite apparent that despite a split the current shape of the lobes means that the U wind off the states doesnt support blocking, but day 9 ( alligned to the trop response ) allows for a different pattern that is complimentary towards the jet being sheared up the western side of Greenland & also residual flow alligned SE in the atlantic - We should also see the vortex 'throwing' Scandi Deep cold SW across Europe - This is the jet flow -( yellow ) & associated areas of deep cold. This is a solid -AO / + PNA / -NAO pattern. This is why the models have suddenly flipped to that sharp NW > SE allignment If you are looking for sustained cold then a SSW split + follow up warmings & continual negative zonal winds are the hallmarks of LONG cold spells, * with the usual caveat that we are the SW point of the cold & could always see some milder air pushing back west * This could be a crippling final quarter of Winter for Europe & the Balkans- Best S
  7. 103 points
    Evening Guys Officially signing off for the winter from my window - still all but 5 inches on the ground - have a great year ! Current favourite See you next year S
  8. 102 points
    I assume the overnight ECM has (temporarily at least) put an end to the glass half empty stuff from some posters yesterday. I'm sure the next variation in op run will bring them back out - but if you are on here to learn and are hunting snow/cold (sad to see that thread go....) then here's a bit of learning for you. The overnight chart from ECM at the later stages of medium range reliability is fabulous. What you are looking for here is the source of the air in situ over the UK - and the angle of approach from the system in coming...and where it will pull its air from. Note here at 216 you have a generally slack E/SE flow over the UK established from the back end of the week to come, with air being drawn to us broadly from Scandy and Northern Europe - already both snowbound and across a north sea that is not especially warm. Meanwhile the incoming low has purples in it in terms of pressure - meaning it has been drawn directly from the deep vortex low over Canada. As it approaches and disrupts against the higher pressure ahead of it - it "slides" southwards and the winds from that system turn to the SE, pulling dry continental air up from France. The final image shows how the moist, atlantic air (still pretty damned cold because of its Canadian origins) has dropped into France. Eastern UK has a feed straight from central Europe - western parts of the UK from a slightly milder France - but the combination is such (especially in January) that snow is likely countrywide. This is a "slider" low - precisely because the atlantic system has come from the NW and literally slid down the face of higher pressure ahead of it. Are there historical parallels? 3 from my memory that show a variety of similar events. The most similar to the one progged here would be Feb 1996 where we had a very similar setup a couple of weeks later in the season. Note again the deep origins of the sliding system (purples) and the cold air in situ from a SE feed. 1996 brought huge snowfalls to some parts - myself fortunately included this time around while in Dorset. Slightly different, but no less impactive in terms of snow, would be 1985 and 1979. 1979 first. Note here that the incoming system is a lot flatter - it's approaching from due west and meeting the trough in place over scandy. On this occcasion the deeper cold was in the resident scandy lobe and less in the approaching system. Note the isobars ahead of the atlantic system turn, once again, to that SE flow and as the higher pressure ot the south drew away plenty of snow fell. Feb 1979 was full of such events - they kept repeating over and over giving blizzards to all parts. This image below, again not a million miles away from where we are heading but with a very convenient wedge of higher pressure just to the north of the UK - brought some of the heaviest snow falls in the last few decades, especially a few days later around Valentine's Day. And last of all 1985. A bit different this one - but if you are wanting to learn about snow giving conditions good to dig out. This time the system approaching from the west runs up against a block that is much more entrenched to our NE - but the effect really is the same. Moist air from the west disrupts against the colder, denser air in a block ahead of it and slides underneath. Because of the angle of trajectory these are sometimes described as channel lows because the atlantic system's slide angle takes it through northern France as it pulls continental air up ahead of it into its moist lead edge, turning all that moisture to snow. Bottom line is - we are approaching a pattern which could replicate any or all of these situations because of the forcings which are in operation. However - and it is a big however - for every one of these big snow makers there are plenty of historical near misses......either because too much warm air gets wrapped into the system or because pressure to the south remains too high and continues to feed warmth up from the south. Putting my own neck on the block here - I don't think these are going to be a factor this time around because of the forcings I described last night at some length....but they MIGHT be. Dont shoot the messenger if it all goes wrong - but if I'm honest I'm feeling pretty good about the alignment of things at present and in particular about the longevity of what may occur. Bear in mind that week beginning 21st January is likely NOT to be the peak of the process. If you prefer computer driven analysis then just look at the oft shown EC images for end of Jan into Feb for evidence....but the downwelling impacts of the SSW and the next phases on pacific forcing say to me that the peak will be somewhere in the last few days of Jan and on into the first couple of weeks of Feb. Historically probably the UK's sweet spot in terms of snow fall. Watch and enjoy the ride.
  9. 101 points
    ??????? Eh? The next 7 to poss more days are signalled as below average!! The next 2 nights look firmly set to be coldest of this autumn!! I suspect there's people so obsessed with snow forecasts that they're not seeing wood for the trees. No cold: no snow. And as I posted above, usual suspects in media aside, nobody sensible has given a snow prognosis 10+ days ahead... because the forecasting science to do so with any reliability doesn't exist. Honestly, compared to some recent winters(!), I fail to see anything in longer range models to make cold lovers moan.
  10. 100 points
    ECMWF Monthly goes off-piste versus it's deterministic brother into & particularly beyond Christmas. The +ve GPH/MSLP anomalies out to our NE merely intensify again towards end of month, then show signs of retrogressing 1st week Jan to lie directly to our North, with mean E flow trending more E-NE with time. Glosea likes the idea of a more blocky Jan too... but the term 'deja vu' springs to mind! Other shenanigans aside, at least Glosea strat diagnostics have been sound last few weeks, so given emergent January signals the PV may yet yield a 'surprise from aloft'. We shall see.
  11. 100 points
    EC Monthly consistent with Glosea and it's last runs. Strong resurgence of +ve MSLP/GPH anomalies north of UK further into Dec, especially Xmas week, with marked -ve temp anomalies developing across adjacent contiguous Europe as N'ly flow veers to mean easterly late Dec. Good to see both suites in such firm agreement, despite inherent issues of confidence at such lead time.
  12. 98 points
    It's all good folks - we are about to get slammed Think March 2013 imprinted on the middle of winter - what's not to love ! The slider solutions are dialled in as the wave guide changes, NW SE sliders will be the key feature of the next 6 weeks as the canadian vortex drains itself via downwelling. No it's not 62 or 47 or 2010 But what it actually is an SSW which we all now respect and have learned from, and have the nuance to watch in real time, spilling its arctic cold guts all over the mid latitudes. I am sorry for those of you who think , nope this is not a driver, nope AAM isnt a driver, MJO isnt a driver, Nino - isnt a driver - you get me? Simply put - they are - and always will be and GWO and AAM possibly the most reliable of the lot! Do not discourage in weather that which you have yet to understand - this science is difficult, no one is ever right, no one is ever perfect, no one on here alludes to that What I want to say is- for us afficiandos of cold, us dedicated individuals, hunting, searching, wanting looking and dissecting everything. We are all good Its near solar min, monster SSW, monster Split. NWP - Bring IT !
  13. 98 points
    That's a good tee up for this.. From a subseasonal and seasonal perspective, the gift that has kept on giving is the pattern over the Maritime Continent. I've used this a lot (to success) over the mid summer and autumn periods as a key driver influencing the hemispheric pattern. It was an excellent lead for the high pressure signal centred over Europe and troughing in the Atlantic. Through September and October, this pattern has remained an only recently has it diverged. This is really useful in understanding why we are getting divergence in the pattern, and key to understanding if or more appropriately when it will return as the key driver. So what am I discussing here ? Well, let's look at the spatial arrangement of sea temperatures across the Indian Ocean and West Pacific. There's a text book signature for enhanced low level westerly winds through the Indian Ocean and easterly winds through the central Pacific. This is evident in surface wind anomalies for the region. Where winds converge, upward movement of anomalously warm air leads to convective activity and again this footprint is evident in rainfall anomalies. What's crucial here is that this convective pattern is mirrored in the upper and mid troposheric levels. Here we see an enhanced (negative) velocity potential associated with a substantive standing wave. Analogues for this provide a clue as to how September - October should have looked.. Compared to observed.. That's actually not a bad match across the Northern hemisphere, allowing for a more blocky type pattern over the Arctic related to other drivers, and particularly within the Atlantic sector. So we have a useful blueprint as to how November and December should pan out, given the likely persistence of the underlying driver, the spatial arrangement of SSTAs in the Indian Ocean and Maritime Continent. However, in the last week we've seen the modelling develop a deviation from this pattern. Why ? The answer to me lies in destructive interference from an emerging MJO wave. GEFS and EC EPS are consistent on the development of a convectively coupled wave moving through the central Pacific and Western Hemisphere (phases 7-8-1). Composite for these phases, and you'll understand why we're seeing the trough signal over NW Europe. Note the development of higher than normal heights over Easter Europe and Western Russia there. That is the perfect geoeffective position for upward wave reflection into the stratosphere. Is that part of the beautiful choreography of the atmosphere to bring about a stratospheric warming end November / early Dec ? So assuming the MJO is a player, where do we go from here ? A stall in the MJO in phases 7 or 8 is unlikely. It rarely gets stuck there. Where it does sometimes linger is the Indian Ocean, phases 1, 2 and 3. This seems unlikely in terms of what we've seen and underlying sea temperatures in the region. That leaves me with a likely return of the convective wave quickly to the Maritime Continent as per GEFS. That may well enhance or excite the standing wave once more. Analogues for this for November / December show a very coherent signal for +ve height anomalies in the mid Atlantic, to which you would need to adjust for greater amplification on the back of zonal wind anomalies (weaker than normal) and warming of the column around Barents Sea. If the GEFS is correct here, we should see a return to the mid Atlantic ridge or even blocking further north in the medium to long range. I would expect to see a Scandinavian trough also emerge. This will be tied into the evolution of the MJO towards phases 4 and 5. One further line of thought is relevant here. As others have keenly observed angular momentum remains disconnected from the ENSO state. For a weak La Nina, we should be seeing -1SD, not +1SD. This is reflective of an atmosphere which is primed for amplification. If the MJO swiftly propagates eastward and enhances the convective / upper level velocity potential over the Maritime Continent, we should see a corresponding upward spike in tendency in relative angular momentum giving a large projection of the GWO towards phase 4. Analogues for this with a ten day lag applied are interesting.. So for the next 10 days or so, cyclonic and troughy over NW Europe, temps not far off average or above. Thereafter, would expect to see a transition to a more blocky type pattern with height rises in the mid Atlantic and points north over time.
  14. 94 points
    Last one from me for 6 weeks before I leave in the morning for Canada . Our experts we use in resort have told me that todays upper air soundings over the Russian Arctic are showing Easterlies now established at 10mb level. They expect this flow direction to run down to the troposphere in the coming days ( the start of the reversing the westerly flow for much of Northern Europe including the British Isles ). This will impact on the models in the next 48 hours. So hopefully some good looking winter charts for you lot just around the corner. Will be watching from far a field with great interest. Bye for now and a happy New Year to all our forum members, young and old ! C
  15. 94 points
    Good afternoon gang ,its nice to be back reading all the posts again ,although i have been lurking .(Thanks to all friends on here for my much appreciated messages over the loss of my wife recently ,THANK YOU ALL ) .Its great to see that the charts are showing some Winter weather , really warms the cockles of my heart .And its the charts which keep us interested not always showing us what we want ,and i,m certain that over the coming winter there will be Prozack moments and of course STella times ,so with the Meteorological Winter looming we can look forward to 364 roughly Runs of the good old GFS ,182 of the ECM , AND HUNDREDS OF OTHERS .Looking around the Internet back last year i looked at many weather forums etc ,and found that ours is by far the best and most interesting around .In my next post i will stay on Topic ,just wanted to start with a light Hearted post today .Let the hunt for Winter Synoptics commence ,Curtain twitching ,hiding behind the settee etc ,cheers gang ,.
  16. 93 points
    EC week 4, let's just say, what price a white christmas ? Genuine -ve temp signal there at that range is stark. Week 3 continues the theme as discussed, cross polar ridging.
  17. 90 points
    Microscale detail absorbing an awful lot of attention on here, when in reality it is a waste of emotion. The macroscale pattern is now fixed - it will not change significantly now for the start of next week, and while we can hopecast for a front/kink/trough to appear in exactly the right place for every IMBY desire it is frankly impossible at 7 days' range. We wouldnt even try to get that right on a standard westerly atlantic pattern - how can we hope to get close to specifics 5 - 10 days out from the main event when we are seeing dramatic events unfold in the strat? Remember - we are still in reversal for several days yet, and the models will have larger than usual error bars on microscale events. We couldnt hope for a better anomaly chart to see in the new month and this is a belter from GEFS to kick off the week on Monday And the strat? By day 10 it has reformed over the pole as the reversal ends, but the shattered remains at 10hpa are weak, and a large eurasian block is still in place while zonal wind profiles recover to weak levels over the pole, but see a very muddled profile at 55/65N suggesting anything but a recovery. Sustained chance for high lat blocks to survive in situ though the storm track will gently slide back north. Battleground snow? Down at 150hpa blocking clearly still in place over Greenland So - 10 days of almost zero chance of a substantial change to the pattern, and decent confidence in any recovery from this point being slow and painful for the vortex. Next week will be very cold as we know...and the week after will also be cold, quite possibly for all parts throughout the week. Confidence then less sure by week 3 - need to see how pacific forcing may impact at that point, and just how quickly (if at all) the vortex recovers. If it is too late for a recovery then kiss goodbye any early spring as cold will continue to spill out at times right through the month in all probability. And what about snow next week? Well - I think all this hand wringing over each individual model is a waste of energy.... but maybe history can help. 3 days before we were hit by substantial snow in 1991 the charts looked like this 3 days before the snow hit in 1987 We are forecast currently to look like this in 72 hours BUT we know we have an SSW in the bag and a signal for sustained blocking and a retrograde pattern Which would you rather have?? Both 1991 and 1987 delivered plenty of snow. What do you think is likely from here if they are analogues to go by in terms of snow fall... - and what about the signals for longevity listed at the top of this rather long post?? The only thing going against us this time is the calendar date. All very very good. People criticising this setup really and truly need to get their history goggles on and then wander off to a quiet corner, tail between legs.
  18. 90 points
    Evening Guys - Well its been an utter rubbish day on the model front- last nights call was based on the european models- more especially the ECM displaying the exact scenario & evolution it did in 2013 & the UKMO had joined the party on the 00z ( tues ) but did move away yesterday 12z- The GFS was to flat to start with & the ECM even at 120 was to amplified- the median point yet again coming out with another stella performance was the UKMO - I cannot praise this mode high enough this year- every single cold spell that hasnt varified- which has been most if not nearly all- The UKMO has never really been on board & perhaps I should have waited till 00z today to post- However when the data is almost identical from the yesteryear right down to the zonal mean dropping again- almost identical to 2013 then it seemed a no brainer. so yep the call was wrong... it may interest a few that this year Im going to work on a new teleconnection, ive not named it yet however it will be based on 2 specific weather patterns that deliver cold for the UK & within that the leads up focussing on MJO data & Strat data - for example, since 1979 there have have probably been around 15 -20 greenland highs - it will be interesting to see my results of what the zonal mean was when these developed, especially in non SSW years - have we had any GHs in non SSW years... Anyway - enjoy your eves -- im as frustrated as anyone ... S
  19. 90 points
    Evening All For those of us who have been here for a long while there is times when you know you have to throw in the towel on chasing cold & times ( very rare ) when you 'just know' that the Cold solution is correct - Today is one of those rare occasions ( last seen nearly 4 years ago ) when what I see developing in the models & more importantly 'how' its developing gives me near 100% confidence that we will see things panning out close to the ECM - Lets recollect the last time this happened & pick these 4 days you will note the start date of the trough dropping south is 13 Jan 2013 The UKMO 4 days before http://www.meteociel.com/modeles/ukmo2.php?jour=9&mois=1&annee=2013&heure=12&archive=1&mode=&ech=72&map=&nh=0&carte=1021 The ECM 4 days before http://www.meteociel.com/modeles/ecmwf.php?jour=9&mois=1&annee=2013&heure=12&archive=1&mode=1&ech=72&map=0&type=0 & the GFS 4 days before http://www.meteociel.fr/modeles/gfse_cartes.php?jour=9&mois=1&annee=2013&heure=12&archive=1&mode=0&ech=6&runpara=0&carte=0 If you run each model through you see the clear issues that GFS has which is eastward bias & not splitting energy .. Today we find ourselves in the same boat- GFS not splitting energy & moving the whole lot eastward- it will take the GFS 24/36 hours to catch up- Its also worth noting why the seasoned campaigners on here show 'little' interest in the ENS means - Assuming the ECM OP is close for day 6 with the ' wedge ' - ( ignore the shortwave flow ) look at yesterdays Day 6 ENS means - very poor from GFS ECM 00z poor 12z ECM 'trending' So those posting Means charts day 8/10/12 - even 16 look so foolish so often ... The only thing to do is reviewing trending... Anyway- sound the alarms - The train has left the station & its on its way !!!! - just follow the evolution from this- http://www.meteociel.fr/modeles/archives/archives.php?day=9&month=1&hour=0&year=2013&map=0&region=&mode=2&type=ncep Moving Over to the strat - The warming that Many of us have been forecasting / following over the last 10 days is now coming to fruition & the initial prognosis of a double dip drop in zonal winds looks to be the form horse ( as opposed to the straight plummet to negative ) The zonal wind @10HPA Over 60N is now is a state of freefall - peak value just 5 days ago was an elevated 48 M/S ( climo for late jan is 30 M/S ) - we will reach the climo line tomorrow & the 20 M/S line 2 days later indicating the deceleration curve is about 5M/S per day - So before the short projected stalling of the first dip the minima will be in 5 days around 18 M/S - There is around 95% agreement ensemble agreement - Post that there is a solid 50/50 split in the warming & deceleration becoming an 'official' SSW with the wind going negative Seen here This is why the albany site forecast doesnt get below zero because its the mean - when in reality its a 50/50 chance with ob iously the lower the better numbers.. What I personally believe about whats happened today in the models - is through high entropy the ECM has resolved the tropospheric response quicker than the GFS -& just highlight This is NOT MJO related for anyone who says it is as its still sat in COD - If you want further proof of the fact that its a tropo response then look no further than the zonal wind data @60N for the dates above - The wedge developed on the 10th of Jan 2013 - This is the merra data Look close the 15M/S day was the 5th, the wedge was there on the 11/12th - see below The was also some pacific response as well - now look at the temps & locations... So in summary: This is 2013 revisited- with 'hopefully' deliver a similar outcome in the short term quick troposheric response as well as the 40-50 day AO profile that encompassed March 13 record breaking -AO as well ( we do probably need the Full SSW to deliver that ) best S
  20. 89 points
    For those who think the SSW was a bust take a look at this at T+3 Then look at the NW/SE jet axis over us, then look at the fact that the downwelling has been delayed but is just underway, and winter is not over by a long way. Then go and read up a bit about SSW's so next time you make a sweeping statement you are doing so from a position of greater knowledge. Thank You
  21. 89 points
    C'mon guys lets give @Paul and the mods a break with the bickering and personal digs type of posts after all it is a WEATHER forum and this thread is for WEATHER MODEL discussion I can only imagine how hard it is for newbies to try and decipher what is going on among all those types of posts so if anybody has any issues with posts / members perhaps it would be better to use the report post button / ignore member button or try and settle it like adults through PM's and also remember the couple of banter threads that exist Now onto the models I will refer back to my post from 8th Jan some statements / thoughts that I made in the post on 8th Jan "I still believe that any low pressures that do develop will begin to take an ever increasing NW - SE track (with the majority perhaps struggling to get much past the UK) resulting in some northerlies / North westerlies bringing the first hints at something cooler / colder to the UK " "My key period for this would be 17th Jan - 21st Jan " starting on this point, I am fairly happy with this still as we move towards those dates as it looks like around the 17th will be the first (of what I think could be quite a few within the next few weeks) at a sliding low attempt dont take the position / strength of the low too seriously as this is still changing from run to run but the NW > SE movement is there and a run showing possible north westerly / northerly / north easterly air by around the 21st onward for a few days onto my next statement / thought from 8th Jan "So what could happen after that?" "Well IMO it looks like being the last week of Jan from around 24th Jan - 31st Jan that the possibility of some fun and games with blocking and colder charts will reach its maximum potential so far this winter." Again I remain pretty confident with this, why? IMO there is still a signal for the last week of Jan for blocking to start to develop / take hold there are some more ensembles showing this but I think this demonstrates my point clearly enough AO still set to nosedive first hints that the NAO might head the same way And with the MJO looking like possibly heading back toward / through phase 6 / 7 by then that could also help aid blocking (again I am only going off my limited knowledge on the MJO and also might need to factor in some lag time) (some of the other MJO forecasts look a bit more uncertain / slower to go toward those phases ATM) Also still worth factoring in effects from the strat warming event(s) that have took place during late December / Early Jan. some more thoughts / statements that I made on 8th Jan "A word of warning / potential spoiler would be a west based - NAO which remains a possibility http://theweathercentre.blogspot.com/2012/10/east-based-v-west-based-negative-nao.html Key Points keep an eye on these beginning to nosedive once the blocking gets nearer https://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.shtml https://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml be wary of the west based -NAO" All of the above are still true / possible IMO but with regards to the west based - NAO perhaps the chances of this wont be know until nearer the last week of Jan and where the models are seeing the potential blocking setting up / developing keep an eye on the ensembles for more and more BOOM type charts appearing in the run up to the last week of Jan I think the first area to focus on ATM would be the potential for slider lows and the possible snowy conditions that they may bring but I still believe the amount of BOOM charts will be on the rise the nearer we get to the last week of Jan. A few extra points I would like to make 1. I wouldn't worry too much about differences in each GEFS suite on the graphs (rises in 850 hPa temps) as slight changes in positions of possible slider lows and later on blocking highs can shift those 850's heavily in one direction or the other and I think we are seeing the usual ebb / flow of the models trying to grasp exactly where each low / high is likely to set up (possibly whilst trying to factor in ongoing effects from start event(s) and MJO etc) 2. How quickly have we seen in the past that things can change and head down a colder / much colder route a la Nov / Dec 2010 & Feb / March 2018 etc (yes there have also been occasions where charts such as "that ECM" where the cold looked like it was on route to the UK and suddenly diverted but I much prefer to look at things with a glass half full rather than immediately thinking that we have no hope / chance of the cold / snow reaching our shores / back gardens) using the 2 years mentioned above as examples and again I am not saying that anything of that severity is heading our way I am just highlighting how much can change within the space of a few weeks (using today's date 14th Jan and 2 weeks from now would have us in the last week of Jan , 28th Jan) taking the 25th November as the end date as that was when the colder air was spreading right across the UK then 2 weeks before was the 11th November 11th November 2010 > 2 weeks later 25th November 2010 11th November 2010 25th November 2010 an example of how quickly things can change / blocking can develop February 2018 - again I will use the 26th February as the end point as this was when the colder air was spreading across the UK so 2 weeks before was the 12th February 2018 > 2 weeks later 26th February 2018 12th February 2018 yes there was some snow around for some but I am highlighting how quickly more blocked conditions can develop 26th February 2018 Keep calm everyone and try and enjoy how the rest of January and beyond plays out, I still think we are in for some fascinating model watching. And I just want to remind people I am certainly no weather expert, I am just having a go at trying to predict where we are heading and seeing how close or far away I am (and if I am miles off the mark I will own up and try and examine the charts to see what happened and how we ended up with scenario A or scenario B etc) ensembles GEM 0z ensembles FNMOC/NOGAPS 0z
  22. 89 points
    After a health scare I have had the best news ever and been given the all clear. What a year it has been weather wise.Just like to take the opportunity to wish Paul,all The moderating team and all the members a very Happy Christmas,Have a break from The forum and enjoy the day with your Family's. Let hope for all us coldies January is a cold and snowy one. All the very best to you all C.S
  23. 87 points
    Another day and another 24 hrs of model watching. Pub was just about to close last night and we had a few big hitters GP, Fergie etc basically said drinks are on the house. “”12z ECMWF ENS set against model climatology lean pretty firmly in median 2m temps towards below avg (at times quite markedly) out to at least 9 Dec. “” “”.and a big intrusion if the N Pacific ridge into the Arctic towards the mid Atlantic ridge. Strongly negative AO latter stages of the EPS”” Tamara adds a few cheeky Christmas charts and it’s a lock in. Someone talks about previous T240 charts not verifying but soon gets drowned out. The curtains are raised at 10pm as we get’’’’’’’…EC Monthly consistent with Glosea Strong resurgence of +ve MSLP/GPH anomalies north of UK further into Dec, especially Xmas week, with marked -ve temp anomalies , Bets are taken on a white Christmas This morning Today's outputs all point to the same trend in terms of some increase in amplification upstream and more digging south of troughing in the Atlantic but early differences mean the weather for the UK could be either a spell of milder sw'erlies or staying cold 06z following the 00z so far with the high sinking south allowing south westerlies to come in though not in a reliable time frame by any means. That’s south westerlies mentioned twice , they better stay outside of the reliable time frame toss*** No real changes in the outputs with the GFS still showing the threat of mild SWlies and the models in general showing a high pressure dominated outlook. Ok that’s enough south westerlies aint going to be a buzz word, If high to drift towards the east and we pick up a SE'ly . To be fair the 06z gets closer to the ukmo output between 120 and 144 hours compared to the 00z by shoving the high more over the uk!but goes default and push everything eastwards after that!! The high says make up your f****** mind where am I going ?? Post T144 the GFS 6z doesn’t want to get rid of that SW direction. Into the afternoon The London 00z ens temperatures post 6/12 show more spread then a tub of lard. GFS is all about the shortwave spoilers. Welcome back short waves , make sure you go in the right direction There is a great degree of divergence between ECM and GFS ensembles ,reflecting how the UK high is modelled, no shi* sherlock This show how FI is T96 as that is where the shortwave dramas will be resolved. A BOOM chart 5/12 is posted UKMO T168 Signs of lower Euro heights, particularly on the UKMO but both an improvement on yesterday's 12z runs. We are starting to see a closed off High with greater chances of feeding continental cold this way Well on the sinking high, Fergie has said it is the favoured outcome but UKMO does not suggest any quick evolution toward that solution. if this trend continues, such as shown at T144hrs.The high holding just a tad further north makes all the difference. I thought it was going south east wtf If you want to avoid the GFS crud start praying the UKMO is correct! Early evening ECM backs ukmo!!! No sign of South westerlies on JMA.JMA the new must have model UKMO 168 continues the eastward propagation of the Iberian low & sends a tighter squeeze of Easterlies over southern England - Very cold surface air 4/10 Cold (1 more to reflect the 2m temps down south maybe -10c near Benson Oxfordshire tonight , who lives near there ?. I took 0.00002 off for folks living in north Scotland milder there) For those that struggle with what’s going on I attach two simplified charts one showing how hard it is to draw marge and one showing marge struggling with the block re where is it going to go.
  24. 86 points
    I think too many have already become desensitised to what constitutes a 'fantastic chart' and the seasonal ailment of this thread (which is irrationally mood driven anyway by the more average synoptic charts that are customarily on offer) has taken on a latest variant of becoming superimposed and twisted on the absurd semantic that 'merely' only UK Tundra conditions are being shown and not the Canadian variety. Truly, if you cannot exercise self control in front of your lap-top by the smorgasbord of dessicating cold solutions evident on NWP, especially as we are heading right into meteorological Spring, then its maybe best that a different form of self torture is considered to spare those who take a more considered perspective. This has nothing to do with any regional bias (coming from a part of the country that relies on these increasingly rare sort of synoptic to get a snow fix) its to do with the usual fascination I have for sitting back and marvelling at watching a pattern like this unfold in the greater macro scale. If/when it snows at home, I will be less inclined to spend spare time waiting for when it is next going to snow, or when its going to end - but instead getting out, having fresh air, exercise and enjoying it. And then, when the snow and ice is over, it will be a case of seeing how the patterns evolve through Spring and into Summer - looking for the best that can be on offer for this Island, whose micro climate is fickle, elusive and overly too mobile to the sort of sustained blocked patterns that can be the deeply cold derivative as upcoming next week, or depictive of deep Azure blue skies, sunshine and warmth of the summer. Get used to this reality - it will always be thus
  25. 85 points
    All roads lead to Rome - or in this case a cold spell. There have been some odd comments on here today, given we are on the cuspy of only our second significant cold spell since 2013, and so I'm going back on my last post - and instead of looking only at short range charts from here it might be good to make some connections and map out the road ahead. Strat first of all. We have seen a slow downwell - no doubt about that - and a fairly chaotic displacement/split event that was uncertain for a while. But the mists have cleared, and the downwelling is finally going to impact more substantially on the trop pattern in the coming days. The atlantic profile for midweek is still fairly flat but the split has worked in our favour, with the Canadian lobe remaining in situ but the more substantial Siberian shard pushing back east towards the pacific. The 150hpa forecast 5 days later quite clearly shows this and you can see the push of energy at 30hpa moving away from Europe over the eastern Siberia with the Canadian shard sitting in place The signal for a resurgent midatlantic ridge up to the N/NW is quite clear. Picture those EC46 images showing more robust northern blocking by month's end - part of downwelling strat forcing. But we have a pacific signal that looks to be marrying up. Our current high has been resilient, but at too low a latitude for our liking. No getting away from that - forecasts a month ago saw the blocking, but saw it further north. The slow speed of strat impacts probably wrecked this possibility. Now torque effectis, apart from in the tropics, have been on their way down....but before long the bounce back up will begin again, and lag effects will time perfectly with maximum impact of strat downwell So we have the beginning of strat impacts to come in 7 - 10 days followed by GLAAM support 7 - 10 days after that. All good. But the story does not end there - the MJO, which on its own was not enough in early Jan to override other factors, is heading swiftly back around to phase 6 - 8 in time for February....so that just as the atmosphere needs a bit more of a bump to keep blocking in place - it gets it. Note also that the MJO is remaining generally active, and poleward wave activity is therefore going to remain a factor in preventing any flat pattern from getting a hold once again. Ventrice filtered plots remain quite impressive So - this takes a pattern of parallel forcings supporting a meridional signal and anything but a westerly atlantic pattern well into February. But let's finish on the strat…..because of all the factors that drive our weather it is becoming increasingly clear that impacts on the vortex that downwell to the trop are dramatic and forceful. The warming that started well over a week ago is just past its peak, but winds at 10hpa are set to remain easterly until the back end of the month, give or take At the same time westerly winds will return at the top. Bad news? Not at all. A return of westerly winds at the top will form part of the ongoing downwelling process - and just as we had a flushing process of westerlies pushed down into the trop round about now, helping neutralise attempts at mid atlantic to greeny height rises, so this flushing out of easterlies will serve to force them onto the trop pattern. Given that the 10hpa pattern will have been reversed for the best part of 4 weeks, we are facing a long process in this regard...and so the gradual recovery of the vortex will actually sustain a reduction in tropospheric westerlies for a long time also - I'd suggest most of February. And then in March the vortex is fading anyway. Will we get anything like enough westerly momentum to change the pattern out of the entrenched cold cycle? I'm not sure we will.....but that is a bit far off to be discussing in detail now. So - forget op runs in 8 or 9 days time that are making it look as though a resurgent trop vortex driven from Canada is about to fire through the atlantic. It isn't. a Canadian trough will remain in place as the strat image is imposed upon it - but the door in the atlantic is going to be slammed shut, and cyclonic energy will have to circulate around the edges. Cold northerlies or undercut scenarios. And if we can get slices of that cold Canadian vortex firing moisture down into Europe over the top, or later on potentially underneath, the block then we get the precipitation we want in a cold phase. This on top of the impacts of deep European snow cover that will help provide a very cold feed off the continent at times when the winds turn E/SE. Long post - apologies - but everything is in place for something a bit special. Stop worrying about NWP. It doesn't get a handle on all these processes well....and while there is no way I would want to call the microscale specifics at anything more than 72/96 hours (and always from UKMO and ECM) - we can sleep easy knowing that the macroscale factors are lining up in favour of snowy goodness for the second half of winter.
  26. 85 points
    Meant to post this last night but some forecasters saying mild Christmas. At this range ,about any thing could turn up ,strange year weather wise so far ,snow in the forecast tomorrow , STORMY with it ,plenty of rain next week and signs now of cold cyclonic next weekend . Our local squirrel s took BEDDING to their winter homes last week , yesterday they threw it out to the local polecats and like ,Today they are collecting it all back .went up woodshed just before sunset today and local vermin were BUSY storing winter food .some very interesting weather ahead I feel ,Stellas all round gang ,I'm usually lurking about as weather is always on my mind ,miss my dear late wife . It's great having this great forum , cheers all .
  27. 85 points
    We have waited a long time to see this. Since the beginning of the internet age. We have all wanted to see these synoptics reel in and in and there is a bit of disbelief now it is happening, Phenomenal is all I can say. And to think that there was some that said that we would struggle to ever see these synoptics again. Well I guess that will be put to rest next week. Big time. Normally to just get the -10ºC 850 isotherm over the country for a day is an achievement so to see multiple days forecast is amazing. Look after any vulnerable neighbours whilst enjoying the freeze - but do enjoy what could be a once in a generation cold spell. I'm sure that it is just a co-incidence that this follows a SSW lol!
  28. 85 points
    ...precisely so, and precisely echoing UKMO thoughts after some recent flip-flopping of output (including yesterday's ECMWF Monthly, which suddenly offered substantial weakening of the previously strong +ve MSLP anomaly north/NW of the UK that it yielded in the run only 3 days prior and in all previous recent runs, for later December. Is it wholly trustworthy, given marked swing? No, not until we see the sense of direction offered in runs on Mon-Thurs next week. The situation currently is that whilst ECMWF now offers just a bland, weak +ve MSLP anomaly to the west of the UK, it equally - and quite starkly - offers no signal either to suggest a markedly zonal, +ve NAO set-up either.... In other words, whilst GloSea still remains more inclined to return a blocked story later through the month (and ever since output run way back in Sept, has not budged from indicating a massive ramp-up in stratospheric zonal winds later Dec, as now being suggested by GEFS), the forecast outlook by the UKMO remains quite reasonable in the current circumstances (not least as it would be easy to overreact to latest ECMWF in isolation). Thus, a return to blocking still remains the more favoured outcome, BUT whereas this always had low confidence (based purely on lead time), we now can add a further tier of uncertainty given ECMWF yesterday and the fact that no clear synoptic regime is obviously favoured after mid-month. Some reactions I've seen on social media have been bordering on hysteria, but there's nothing that suggests 'Dec 2015 Revisited' has suddenly manifested in model output. So it looks set to get milder through next week.... but does that really automatically, unquestionably characterise a whole winter ahead??? Deary-me ;-)
  29. 83 points
    New EC weeks 3 and 4 as you were. High pressure in all the right places.
  30. 83 points
    So post about it then, people aren't here to service your requirements for model info. If you're interested in what's happening in a particular part of the country, take a look at the models and comment on it yourself, rather than just moaning. Alternatively there are also many people talking more generally and not just about the low who's posts you can read. This North Vs south thing needs to stop now, before those persisting with it end up not being able to post in here, it's tedious.
  31. 82 points
    I'm starting think that for some in here following the models is a form of self-flagellation. I mean, you have lots of expert views giving lots of details on the overall signals and direction of travel at the moment and you have that same general theme showing on virtually all of the models a lot of the time. And still on every single run, there are the same people over analysing them to the nth degree either getting caught up in will it won't it snow / how much in various localities at 10 days or so out (always a pointless exercise), or on milder runs it's like that particular model just shot bambi and is responsible for the end of any cold weather ever. Things are happening in the atmosphere right now, the most likely direction of travel is a cold one. The models are a bit up and down due to all that's going on, and so therefore, surely, unless you just want to create drama the answer is to accept that fact and not get hung up on every single run of every single model?
  32. 81 points
    Afternoon All- So before we run out on the 12s I thought I would run through the evolution / possibilities - * I think its safe to say that in the history of model watching other than 2010 for snow that has got to have been the best GFS run ever - encapsulated by these x2 charts- -20 T2M anomalies is net the same as having a maxima of 0c in august ( in comparison ) thats how cold it is V the norm. So what was mentioned earlier is 2 distinct phases we seen from the 06z, one the longwave pattern - IE the main blocking High pressures & the more detailed shortwave pattern that is the movement of low pressures / shortwaves & crucially the triggers for pulses of WAA & CAA- Yesterday when round 2 of cold seemed 50/50 ( mainly from the GFS ) my talkinh point was the potential phasing of the 2 low pressures over the NE of US- here was the 12z 132 chart & the 18z 126 under the microscope The first chart shows the energy digging south & not allowing the high pressure from the atlantic to ridge NW - the 18z was an improvement because it clearly showed the potential for ridging to evolve... we now see the 06resolution for the same timeframe- ( but 12/18 hours closer in terms of resolution ) we see the energy is no longer digging south because that ridge from the NE states ( otherwise known as -PNA ridge ) has just poked its nose eastwards- This was 100% crucial this happened because when the jet does start to amplify some 24-48 hours later it moved the placement of the low eastwards & it starts cutting SE over iceland instead of SW greenland - the net result of all this is this 'trigger' low is going down the east of our UK high pressure instead of the west - seen here - So 144 tonight is the 'point' of no return tonight in terms of phase 2 of cold & it hitting the uk at @168 - specifics TBC however the 168 mean suggests a flow somewhere close to NW swinging to Northerly at 192- * The reason I have slide the shots over to the left on the NH is to show the clear example of the atlantic pressure forcing a split in jet energy over SE greenland- note the x2 low pressures one going SSE into the atlantic & one going NNE up to the pole. At 192 The second crucial phase of the longwave pattern sets us up for 'sustainability' of the cold spell & is the 'tricky' bit of the hurdles we have to get over- Its all about how much forcing & split is applied on the jet by the high pressure ( wave ) developing over southern greenland - 1 Direct way to measure our potential success 2/3 down the line would be focussing on those 2 lows & their vectors @192 - * The north west Greenland one ideally needs to be going NNE between a range of say 10 degrees & 20/25 degrees * The one in the atlantic needs to be going SSE - between 135-165 degrees - note the 06z angles More or less perfect @ 216 - with ECM below, equally as awsome So x2 clear phases of development from 144-216 * how much ridging we get through the middle & how much of a wave northwards does it create - - The jet profile from 00z to 06z at 192 suggests the same pattern just a biggger wave amplitude on the 06z- ( 06 first ) So with reference to @frosty ground who I said to earlier - should we get to 192 with this type of jet with an amplitude to 80N which screams back south then the cold @ 216-240-264 is all but guarenteed from the east- Thats because you are a lobe of sub -20c air sitting on its northern flank- you have the jet pulling it south & the low wedging the cold air west- * post that the jet alligns perfect to have low pressure arriving from the NE into the deep cold meaning nothing but snow for the UK-- so the landmarks are 120-144 high pressure wedged into NW atlantic as much as possible 168-192 high amplitude wave - as much as possible over western greenland to create the loop 192 >>>> jet dives south to take the trigger low with it- chances -- 60-70% to get the loop & cold from the North & 25% is to get the surge westwards from the east as recent years havent seen a high enough amplitude & all the cold goes west through Northern France... ciao S
  33. 81 points
    Given that today's EC Seasonal update remains steadfast on broadscale lack of zonality J-F-M, retaining it's eagerness for marked northern +ve GPH/MSLP and drier than avg anomalies, I'm not expecting any sudden change of tact from UKMO Seasonal Team based on current op modelling mash-up. What is now very striking is the growing evidence of apparent disconnect between impending and strongly-signalled upshift in stratospheric zonal winds, versus zero evidence in EC Seasonal for it to manifest in a marked change of mean tropospheric anomalies (towards zonality). I'm trying to discover via UKMO Seasonal boffins exactly *what* forcing mechanism could be overridingly at play here, because (despite the snipers/doubters on here) it is quite irrefutable that *something* is driving these two key high-end coupled models (EC & GLOSEA) to reach similar prognoses. Fascinating enigma; fascinating times...
  34. 81 points
    Two examples of two people who appear each winter as boorish armchair critics who concentrate on taking apart people who make an effort to offer an opinion (based on whatever research), but offer nothing/nada themselves. This type of repetitious stuff is far more negative and lacking in constructive purpose than anything disappointing that doesn't satiate weather preferences as offered by the computer models Have a nice evening, whatever the ECM extended offers
  35. 80 points
    Afternoon so 2 hours on the train should be plenty of time for a post- The last 2 weeks the projected SSW has gradually worked through the models & is now 'imminent' ~ 30hours away is when we go negative on the zonal wind @10HPA/ 60N. But I guess many onlookers will be wondering why the distain for the GFS V the Euros, is it really that bad. Well sadly yes it is. The failure of the GFS is going to be 2 fold here. 1) Identity of type of SSW - Split or displacement. 2) Non propergating ENSEMBLES. So going by the first point, this refers to a models ability to 'see' what that Stratospheric energy & warming looks like at the height of the strat, you have 'high top' models - highest being Glosea then ECM, you also have non High top - GFS which IIRC is 64km V Glosea ~80KM. IIRC ECM vertical resolution is closer to the Glosea. The GFS being poor resolution & the ENS being even lower resolution means that the ability to resolve / locate & then split energy is much inferior to the Euro model, as a result the model will see a 'blob' of warming however wont be able to see the warming plus energy splitting, thats above its means. So the GFS can be scored reasonable for the 'identification' of a warmer- even taking into consideration the errors in actual timings - however its score rapidly decreases if you want resolution to a Split V Displacement- NB here is the GFS elipses about 10 days ago- You will see the GFS ENS green & operational orange not being able to pinpoint a split - ( which the sparked masses of debate on twitter from people who should know better than to use the GFS ) If we compare this to the high top ECM, whilst similar to the GFS in timing errors the actual resolution of the SSW was pretty much bang on. Why is this important - What we are currently seeing is a QTR to the split as the Troposhere mirrors the stratosphere split, however why did it take days for the GFS to see the first ridge & cutting trough over Scandi- Why was it always East!???? Simple- The 'Eastward' (E) energy from the zonal wind was incorrectly modelled - NB GFS model 'E' v ECM (E) * remember take the Eastward component * The poor modelling of the (E) component for about 5 days up until about Fri Eve / Sat AM drove a fairly uniform Eastward motion around our part of the globe, hence with the scandi tough there was a fairly amplitude inflection point meaning its bend & southerly element was low -GFS catapulting it Eastward- Then slowly as the warming proergated down from 1HPA to lower 5HPA & into the GFS comfort zone so the GFS picks up the split- We now look at todays elipses - for day 4/5 Its finally caught up 96/120 & hey presto its on the same page as the Euros now.... ( At least for the time being ) So onto point 2 - GFS propergation issues. The modelling of the strat is generally difficult especially the coupling of a downward propergating SSW to the troposhere, so again only the highest resolved models will pick it up- it appears the GFS has coupling issues as the its ENS suites for the past 5 days have stopped it fully propergating ( again creating much speculation on here & twitter ) all again annoyingly GFS based- Here is the NAM index which shows how the SSW is progressing with negative vales indicating propergation NB GFS ENS 3 - 7 days ago = Non propergation. 100HPA is where we want it to reach ! Notice it stops short - So the ensemble suite from maybe Weds onwards up to around Yesterday wasnt seeing that wave come down - hence a lot of people were looking 10/12/14 days out in the ENS for high lattitude blocking when infact it was never going to appear- Whilst the ECM had already picked up the deceleration at 100HPA for day 10 ( 26/12 ) day 1 & day 10 char So again, ECM was already factoring in a decelerating jet - hence the operational model runs showing a maintained blocked response out to day 10 with higher & higher potential. The GFS has cottoned on now though- Todays ENS @100HPA show the GFS dropping nicely ( NB how poor the operational is though in orange ) Pic 1 ENS from 5 days ago flatlining the 100HPA wind V todays dropping it from 10 to around 4 M/S The main dip comes down around the 8-10th & guess what thats why we are seeing High lattitude blocking now appearing in the GFS ENS - its not a coincidence !!!! Now that the split is in range & the GFS is picking up on the correct outcome in terms of deceleration so the gulf between the GFS v the EUROs should reduce this week as they are working on the same stratospheric & zonal wind speed data now -But never forget how bias the GFS is in terms of powering up that jet.... Propergation is alligned to the 10th Jan - ( which is about 2-3 days later than initially progged ) Dates for propensity of lowest -AO values 10-20th Jan.... Cheers S
  36. 80 points
    Well it's probably fair to say that I've been rather quiet on these forums for the last few years really, especially since 2013. After 15 years of internet weather watching, and more importantly, having witnessed the incredible run of winters we had from 2009-2013 (vs the more Ian Brown style winter in the preceding 10 years), it really takes something now to get me to show more than a fleeting interest in what's on offer. Now it's safe to say, regardless of geographical bias (bearing in mind I now work in Central London and live on the SE'ern edges of our ever-warmer capital, so I am pretty neutral when I say this) this winter has, thus far, been the most productive for watchers of a colder persuasion since March 2013, with many parts of the country seeing at least a covering and some lucky folks through Central England seeing 3 pretty decent, if temporary, snow events (of course those further North and more vertical than the rest of us have seen far in excess of this, but those lucky b******s get to see this most years). But what we stand on the cusp of, what is being modelled within a pretty reliable timeframe, is reminiscent of those days back at the beginning of this decade where the sun went to sleep and cold chaos ensued. It is far to say that, beyond just the pure pornographic synoptics, the likes of which we had not seen for many years previous, 2010 ruined the laws of model watching in so many ways. Forecast models are not supposed to pick out the correct pattern at +360 and run with them pretty much right through to +0. They're supposed to tease us with big greeny highs, fallible dreams of the biggest snowstorms of the last 100 years (circa December 2012) and then leave us distraught, crying in the corner of the shower, attacking the 'mildies' on here with our not-quite-waterproof smartphones (what a long way we have come...) at even the merest hint of an 'I told you so'. And I genuinely think the 2010 episode of near flawless modelling has left a lot of people on here far too expectant of the capabilities of predicting the friggin future with a lot of electronic circuitry and fans. This is why, more so than at any time in the past 5 or so years, this current phase of modelling really has my interest. We are on the cusp of something which, pre the 2009-2013 phase, would have had me online from 8am-10pm (which, if memory serves, is when the old BBC slowwatch forums used to shut for the night) in a far too nerdy way (nobody ever understands our snow obsession right?). Some members on here can be accused of being just that little bit too optimistic when it comes to cold and snow chances, but those same people are very much correct in these sort of short-range cold shock scenarios - whilst the models might not yet show anything significant snowfall wise, they never do until much closer to the time. In fact, if we think of events such as Jan 2003, Jan 2004, Feb 2005, Feb 2009, Jan 2010 and even in to Feb 2012, Jan & March 2013, all of them had modelling which at face value painted a cold and dry scenario....which continued until a few days before unexpected features popped up in an increasingly unstable flow given a significantly lower than usual upper temperature profile. When you combine that with the anomalously warm seas surrounding the UK right now, there is an inevitability about unexpected short range snow events. Beyond just next week, we also have a pretty consistently modelled significant warming into the stratosphere, which should yield an interesting second half of February, combined (or perhaps even coupled?) with one of the most significant MJO episodes we have seen to leave us on the cusp of a pretty memorable February overall...now when have we seen that before, with a declining solar profile...memories of 2009. Enjoy the next few weeks everyone, I will certainly be more active on here as we stand on the edge of what, from 15 years of experience, feels like a pretty significant period of wintry weather for our humble little island.
  37. 79 points
    I wish you guys could see the precip charts on the EC. Serious disruption Tues and Wed on this run across swathes of the country.
  38. 78 points
    I'm sorry for being off topic but I'm sure mods will forgive me for this one. Very sorry to hear you're missing your wife, this time of year can be especially hard and you can't just switch off that sort of emotion. That said, I always smile when I read your posts and I'm sure many others feel the same. All the best. It's always a pleasure having you around.
  39. 78 points
    Just had to talk to the wife for an entire hour!! Please don’t let that happen again ECM mean looked very good, here’s the graph, op on the cold side from D7 -10 Anyone got the UKMO D7?
  40. 78 points
    In days of old, When nights were cold, And models weren't invented, We might have hoped, we might have prayed, But we didn't drive ourselves demented. The MJO the QBO, No wonders such as these, All we had back then my dears, Was Uncle Bert's dodgy knees. He'd hobble along with back bent low, Telling all who passed 'it's goin ta snow' 'They're aching bad' he'd say, 'eee I wish I were fitter', 'You mark me words ma lass, tis goin to be bitter'. More often than not he was right, A deep white carpet fell through the night, We'd wake up to an eerie glow, First words of the day...'Yippee, SNOW!' Those days are gone, but not forgotten, Few snowy days now, seems so rotten, What will it take to make dreams come true? A long fetch beast, a bolt from the blue? A slumbering Sun? A boiling hot strat? A volcanic eruption? Dear God please, give us all that. When I was little, I'd be told, 'Yer won't like it so much when you're old' Mummy dear, I'm afraid it fell on deaf ears, I'm as bad as I was, so I'm here with the seers, I look at the charts with their purple and blue, It's all double dutch, I'm reliant on you, I've read and I've studied, I've tried and I've tried, Still makes no sense, my brain must be fried I understand there's lows and there's highs And a beast from the east makes white stuff fall from the skies But down here in the soggy south west I fear it will mean just slush at best I'm not giving up on those dreams from before, When I lived further North, instead of south of the M4, It must still be possible to get a battleground, Hopes of it happening are still around Down here we must settle for the dribs and the drabs, Seems snow is still out there, it's up for grabs, What must we do to get it to come here? Or do we just get to drown our sorrows with beer? The easterly beast that all winter's been bumbling, Will it get it together or carry on rumbling? How hard can it be to waft this way? All together now, let us pray. There'd be whoops of delight and cries full of cheer If we wake up one morning and find that it's here Open the curtains, let out a shout, 'See, I told you that's what the models were on about' Oh how I hope those dreams come true, But as I said, I'm reliant on you, Please be honest, please don't bicker, It makes reading these pages so much quicker. So finally before I go, To dream of the day we do get snow, To Paul and the Mods, be kind, please, Just lightening the mood of the FI tease.
  41. 78 points
    EC MONTHLY: again like last run. Blocked & dry anomalies developing 1st half Jan as heights move W to north of UK. Colder than avg anomalies southern UK 2nd week Jan (not seen that signal for a while!). East-NE flow. So continuity between last runs and ditto with GloSea5. Don't shoot messenger. Just describing the output: not making any comment on outcome.
  42. 77 points
    Pondering evolution and longevity today. It's taken it's time in coming - and I will do a longer post later tying in the thoughts of December and early January into what is happening now - but the gloom of 5 days ago seems a distant memory as the blocks begin to drop into place. In Dec 2010 we got a very swift transition to a deep scandy trough supported by a very sharp and strong greeny high - but it wasnt particularly long lived. It started to fade within a week because all the drivers were moving things back to a mobile pattern, and then the rest of the winter was unmemorable. This time around we have a much slower evolution - but the blocks are in place for a much more sustained affair. The initial cyclonic euro/scandy blast wont be quite as severe or swift as 2010 because we havent got the same strong block surging up over greeny BUT we are in the heart of winter rather than at the outer edge and with pacific signals remaining on track and a slow strat process suggesting slow but positive evolutions ahead we could find ourselves in a pattern that sustains the cold and, at this time of year, brings plenty of snow from this predominantly cyclonic signal, at least in the medium term. Might we see mention of blizzards in parts? Quite possible. Longer term more entrenched cold, maybe a bit less precipitation. The potential for a noteworthy spell of weather that can be mentioned in the same sentences as Dec 10, Jan 13, March 18 looks on the cards. I'm breathing a sigh of relief and putting the knitting needles away - for a short time doubt began to creep in as to whether synergy of pacific and strat would work out as all instincts and understanding suggested - but today all is clicking nicely. I wouldnt bother wondering or asking where it will snow for a good while yet - but with a bit of luck and a half decent roll of the synoptic dice we can get at least one solid front to cross the country to give everyone a shot, and plenty of convective action pushing inland. Window of opportunity from Friday next week - but probably midway through the following week for maximum chances. And dont expect this pattern to return anywhere close to mild (or even average) for a while. For a little bit we can afford to put the teleconnective charts away and forget macroscale pattern drivers, and instead enjoy a bit of fax chart scrutiny, weather radar updates and even some lamp post action. Lovely.
  43. 77 points
    Another great day of model output with no concerns from me with what is shown. 2 points First is that the worst model output that we have seen today and the last few days is far better than the best output that we have seen for many a year. So don't be concerned with operational variations. The second is that normally any shortwaves scuppers any cold spell, but in this case I welcome shortwaves because once that cold air is embedded ( and movement will always be west of the general pattern), then we have shortwave snow making machines on our hands. The more shortwaves the better as far as I am concerned because the large Greenland block will keep us embedded in deep cold.... Just enjoy the output and whatever it brings.
  44. 76 points
    I won't say much, might jinx it, but now full set of EC Clusters are out there is a rather large area of high pressure setting up shop over Greenland and across northern polar regions in general towards the end of the run, which is 360hr so the 14th of December. There is a population of 23 members showing this, the other 28 simply show yet another blocking high developing over the UK but with this showing some northern development too. Building blocks... Matt.
  45. 76 points
    ECMWF Seasonal just released: extensive +ve GPH/MSLP to N/NW/NE of UK through its D-J-F suite. Consistent signal with last run.
  46. 75 points
    Well - ho hum - let's have a sit rep. My eyes are hanging out on stalks. The pacific first - engine of the climate system. How is our AAM looking in the face of the current high amplitude MJO? Tendency off the chart. How is our mountain torque input responding to the parallel rise in frictional torque? Off the chart. And the MJO itself? Well - not off the scale but not far off it. What does this mean? In a nutshell - strong pacific signal for high latitude blocking as AAM in northern latitudes falls and sub tropical high pressure gets the rug pulled out from underneath. Wouldnt it be great if this could happen in tandem with positive developments in the arctic stratosphere? Ummm - ok - funny that... 100% support now from the GEFS for a reversal at 10hpa 60N as a result of this: Huge burst of flux energy being punched straight into the vortex in the next week or so resulting in all the pandemonium on twitter today from the strat brigade. Flux angle is straight upwards - smashing into the poor vortex and giving it all kinds of grief End result: Vortex split in half in about a week's time just prior to the reversal. Proper SSW in sight - even the MetO have publicly advertised this today. What does this mean on the ground? Double whammy. Pacific forcing is pumping up high lat blocks - phase 7 composite for Scandy - while up above the vortex splits, slows, gets all in a muddle and ends up dropping one shard of the vortex over Russia and perhaps European Russia. End result - even stronger signal for the Scandy high that is already in place thanks to pacific forcing.... and a reversed flow via displaced vortex shard encouraging cold continental easterlies under the block. Length of spell hard to be precise... but certainly more than a few days. A double whammy like this would leave a strong blocked signal in place for more than a week at least - maybe longer depending on just how battered the vortex is and how quickly it could reform. Eyes still out on stalks. This is definitely a one in 10 year event - and actually it might be more than that. Cohen is advertising 1985 as the last time we had a vortex split like this one... and we ended up with this around 2 weeks later Response time for our current event looks likely to be less than 2 weeks - Chio reckons pretty instantaneous. So - are charts like this on GFS for the return to school after half term likely to come off? Yes they are. Potential is there for this to be one of our big periods of weather that gets marked in the history books. 81, 85, 87, 91, 96, 10 - and maybe now 18. Can it go wrong? Of course - as fast as it went right... but who gives a stuff about that right now. The dominoes are currently aligned... so no gloom required. And the dominoes are looking steady.... Funny. 10 days ago I was gloomily expecting the final pacific cycle of the season to be as tame as the last 2 and to give us at best a mid lat block in the face of unremarkable looking conditions. Omega block... bit of frosty gloom... the best of a poor season thought I. Strat forecasts looked moderate - no sign of a reversal if we are honest... MetO forecast nowhere near mentioning "very cold." And now we are looking at something potentially special (though note this is NOT a snow forecast because getting the cold in is only half the battle... the other half is getting the precipitation and that requires some luck.) Now... where's my hat and gloves? Not needed them in Somerset for a very long while.... tropical moths probably got 'em.
  47. 75 points
    You know what - I havent seen 1 hopecast on here. People have put all their points of view across in a pretty good mannor- infact its been pretty good debate. The only post that sticks out a mile as pointless is the one im quoting...
  48. 75 points
    Worth adding that latest EC Monthly again raises GPH/MSLP to our NW with mean N'ly flow as we switch into Dec. Interestingly it then also develops (2nd week Dec) quite marked -ve GPH anomaly from Scandinavia to the UK, coupled to equally marked -ve MSLP across S UK and directly eastwards into adjacent NW Europe, with attendant appearance of +ve PPN anomalies by that stage. Fascinating times indeed.
  49. 74 points
    So this is a difficult post- Trying to illustrate the GFS trending & How its moving towards the UKMO every 6 hours... We have to go from this ( yesterday ) 12Z 180 To this ( Note the its SAME timeframe ) * the First chart is yesterdays 12Z at 180 - we will run each GFS from there & show how it changes- * to the above chart ( the forecast ) - where the winds across Europe are Easterly all the way into the UK - Key differences. - GFS yesterday has ALL the flow westerly across Europe, No proper ridge ahead of the low in Scandi & least of all NO easterly flow across Europe. So yesterdays 18z 174 Chart continues the stark westerly flow - look where the cut off low is- all the way in SE Europe, there is NO net easterly flow in Europe & NO high pressure over Scandi- So todays 00z 168 Chart- Still emphasis on the westerly flow - - Look where the cut off low is - its edged west, also there is more atlantic amplification - however it doesn't make to much difference- there is still no Easterly flow across Europe. So todays 06z 162 - Changes afoot? - Hang on Where did the ridge suddenly appear from?- The GFS is suddenly making more of the amplification than before & squeezing some heights ahead of the low, Also notice Europe now all of a sudden has some NE flow, meaning instead of the deep cold being swept away its actually being held in situ -perhaps nudging west- So todays 12z 156 - More changes? - Look at that ridge !! Now more pronounced & all of a sudden theres Easterly Flow across Europe pushing West, also the jet is more acute. -- * These 4 runs show the GFS is slowing down its forward momentum in line with the UKMO, becoming slower- From ZERO ridge @ 180 to a pronounced ridge @ 156 all in the space of 24 hours!! - What will the T134 GFS look like tomorrow- This ridge will only become more apparent & more supported if the deepening low off the Eastern US - 132-144 hugs the coast & amplifies the pattern The GFS hasn't resolved this yet as it keeps recurving it off the coast early- However it is moving towards the UKMO tonight- If you look at all 5 images go from 1 to 5 notice2 key things * The high is sharpened up & the pacific low is slower & has a negative tilt in the last frame.... So the key developments are above to the NORTH of the UK & also in the deep south of the states at T96 - where the GFS is faster than UKMO - see here- UKMO coming up sharp, GFS is shallow I hope this helps people trying to understand why the GFS is flat & the UKMO is much much better - GFS has an eastward bias as we all know S
  50. 74 points
    Afternoon All - Firstly appologies for postings yesterday, I think seeing a bit of red on here then getting the same over on TWO stoked up the fire so to speak -- ( @JohnP speechless would be an upgrade lol ) Anyway-- I posted the same on TWO so I will post it on here ( & TEITS et'al some of it is a reply to your comments -) I think many on here perhaps have me wrong- most people on here like to post / read the balanced view- however thats not really for me, we know that for every cold output past 96 there is a balanced view that could counter any potential cold- we have been there so many times its almost pointless raising the concerns as we should just 'know' all I like to do now is add in the probability chance of whats being modelled occuring ( 60/40 etc ) I will always highlight the possible route to cold as thats what most of us want .. but remember the probability that comes with it... just as a one off though- The balanced view yesterday indicated that the jet be weak enough to allow a for mid lattitude ridge to bump the flow over scandi creating high pressure in situ over central Europe, because the jet is pretty much uninterupted to the North we cannot get any retrograde blocking until the flow weakens - which is north of day 10- Past that the 00z OP tried to develop a split jet allowing a large element of amplification with a big modality swing in the AO from neutral to negative, the problem being that at that distance resolution is poor & the mean doesnt support such amplitude. The mid term forecast is therefor a continuation of mildness from the west with perhaps enough amplitude in the initial high to creep some colder continental flow into the SE as highlighted by MHugo on twitter ref lowering theta E temps ( otherwise 'coined' as faux cold ) Personally I dont think it will make it this far west as the global 60N zonal mean has increased every day towards an outlook that has more than 50% of the members of its mean over the long term climo ave CFS long term goes on to increase this into Jan ( but it is volatile ) So Why did I ( & the NW team perhaps ) go for a 'front loaded winter' - what does it mean ? For 'ME' I dont really have any interest in the teleconnections per say, that is simply because they rarely deliver any success in terms of forecasting other that when the major player ENSO completely bulldozes the NH pattern with a super Nino- What I do follow though is the zonal wind (u) @ 10 HPA across 60N - that gives us a real time framework of where the vortex is in terms of (u) zonal component & if its weak some guage of the meridional component- Its also the end result of all the trop forcing on the strat - 'the sum of all' The ECMWF compiled a data file of All zonal wind speeds back to 1957 called ERA40 & then redid them at a better resolution called Interim ERA for 1979- 2015- Whilst the data is not publicly available the key element from this is the climo line that this dataset produced to give us a steer from Nov-March where we should be on the zonal winds. ( I would love a breakdown though of the DJFM seasons though to correlate to our CET & AO/NAO couplet ) There are some key dates & info in climo ( see below ) that we should really get to know as well as records of peaks speeds & lowest speeds- for instance surprise surprise 2015 set many 'day' peak records & yesterday Dec 1981 was the lowest record - again think about that month in the context of blocking. So key dates.. - all speeds are zonal (u) wind- December 1st sees a climo ave of 30 M/S westerly ( propergating eastwards ) December 25th sees a climo ave 'peak' of 38 M/S - ironic that its xmas day - so from a winters perspective that period from about 20th -30th the NH is at a time that will have the least amount of blocking. January 15th- Feb 1st is the biggest reduction of the zonal wind across winter as the PV starts to breakdown Feb 20th onwards sees the windspeed at less than 50% of the December peak - Which is why traditionally our cold spells do come around & just after valentines day ... 2015 /16 had 3 peak record dates 07th dec -55 M/S 01st Jan -65 M/S 23rd Jan- 73 M/S - the highest ever zonal windspeed ever recorded in the ERA interim dataset. lowest was a reversal after warming at -30M/S in late Jan ( not aure what year poss 2009 ) Interestingly part of the reason why this years vortex has been slow off the mark is from the super Stratospheric Warming in early march - where the zonal wind speed dropped to -28M/S here was the warming at the start- the official SSW classification date IIRC was 4th or 5th... So we have an idea of why The zonal mean is important for forecasting - Whats important here ia equating the average wind speed with what you would 'expect' to see in the NH in terms of blocking- so December especially @ peak would have NO HLB ( 30-35 M/S ) & 1 maybe 2 max MLB- whether that be - -EPO/+PNA/-NAO/-POL...... The AO would be slightly positive 0 -+1. Whilst there is no pier reviewed paper you could then work on what a 2 wave pattern might look like in terms of being available - perhaps 0-10 M/S & a full 4 wave pattern would ve a reversal of zonal winds. so why a front loaded winter? On the 22nd of November we had a zonal speed of around +18 M/S & was presented with that high beginning to ridge NW from the UK At that very point every single GFS strat ensemble had total agreement on the windspeed dropping to a record breaking -5 M/S ( Easterly ) on the second of Dec - This against the backdrop of record breaking Neg OCT AO & the record breaking SAI for Oct, plus the below ave Nov was enough to convince me that the high would retrograde NW, so anyone thinking my forecasts for retrogression was bias to cold or non rationalised thinking would be incorrect- here was the chart - GFS ens in green From that very date ( 20th ) to today the 6th & importantly CONTINUING the Ensemble suite has gone from total agreement of a -5 easterly to quickly moving away from that figure to a varified figure on the 2nd of +12 M/S - a net change of +17 M/S - which in terms of our little patch has been the difference of retrograde or in the case now - to much positive eastward movement & SW winds- This in itself isnt the end of the world, however the following forecast for the next 5 days is a rapid increase to about 38 M/S - we have then breeched the average line & heading skwards towards 2015 ! This is TODAYS - start point is 20.5 M/S The ensembles have been trending worse & worse daily- Post peak in day 6 there is a small dip then the 10-16 day repeak at 40M/S. Which will ensure theres no COLD scandi high- it will be a positive AO - Of course the ensembles could backtrack - but generally the reversal of fortune is only apparent when predicting reversals, when they go for a very positive mean then they usually dont backtrack. The reason this is so bad is if we peak over 40 it ties in with late Dec & will have a lag of at least 2-3 WEEKS if theres a warming- So thats why theres so much annoyance.. the next 5 days will varify however if 5-16 come close you can write off any proper HLB until Mid jan is we get a SSW- **INFACT WE ARE NOW HEAVILY RELYING ON A SSW TO RESCUE OUR WINTER** we are left with a low amplitude 1 possibly 2 wave pattern - heights up to 70N if were lucky- suggested locations - Western pacific & Central Europe This means my forecast would be revised to nothing of any snow note for England other that maybe 1/2 very transitory events between now & Jan 15th- Scotland maybe 3-4 No sustained cold - with the exception if were lucky, of the good ol 'faux cold' -- I suspect that all the Glosea decent blocky runs were in response to the weakened zonal flow, now as the reality hits you will note the signal has been changed to bimodal - & when it next runs in a week or so If the forecast above has landed then it will be 1 way traffic- cheers s
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