SMU

A split in the models tonights its the JMA & UKMO v the GFS & ECM the angle & ridging at 144 then manifests at 192 ECM flat as a witches T*T the JMA / UK Met more amplified Form horse the middle ground 3/4 day toppler with options post that s

So another hour before ECM - 1 hour spare UKMO tonight Is good, at 168 we still don't squeeze much ridging up towards the arctic but some ridging would have the net effect of slowing the jet down- Also a bonus MAY be that the even though the block may collapse it could hold back far enough west that we stay in the cold & snowy unsettled flow ( that is very rare) anyway what I thought id do is show as many Greenland Highs & how they develop from the archives - & show they don't come from this set up- There hasn't been many ( IF ANY ) - that have come from a mid latitude Canadian block- the base area to look is a scandi retrograde or a resurgent azores high - ( the ECM I think yesterday had one at day 10- with the tell tail circulation pattern -( see my last pic ) Theres nothing to be unduly unhappy tonight- we aren't getting the holy grail to start with but as said above as long as we get some transient heights into western Greenland ( the more the merrier ) then the jet will slow down & hopefully dive SE - we will then be left with a polar high & an azores ridge that may have another go of driving North.... 1955 scandi retrograde 1955 feb azores ridge Jan 1958 - Azores High December 1962 - Azores & Scandi retrograde ( the best ) 1968 - Azores ridge 1970 - azores high more recently... JAN 2004 thundersnow March 2006 Scandi & azores High retrograde 2009 - Uk Azores High 2010 the azores & scandi retrograde THE DADDY ECM 12z yesterday... chances chances....

Pretty nice UKMO tonight ignoring the discussion around the ridging to greenland, the UKMO makes the most of getting the core of low east of the UK allowing for the coldest of 850s to surge south- interestingly energy coming up from the SW at 144 may increase snow potential! s

because at that point ALL the models had ALL the energy moving NE - when infact the probability would be that some broke away SE- in turns out that not enough went SE - but the energy that has has had a net result of a swing of 8c @850 HPA for London - & for that alone the models were effectively useless for the English weather prediction..... In lamens terms we have gone from mild rain to cold rain- not quite to snow..... If you refer to the post earlier where is showed the actual change or projection from day 6 of the GFS to the now day 2 chart then you should 'unconfuse' yourself : )

In terms of the first paragraph- didnt know that also I dont really read anyones posts per say - when I scroll down the page I just browse whats on that page - which is why I dont quote many posts i dont have much time to post anymore- but when I read stuff that I dont really agree with then I reply- In terms of Stewarts forecast for the NAO for week 3 - well its now duly noted & I will keep an eye on it - although that in itself is onky valuable for the UK if it manifests in a cold NAO ie east based - i think I remember the NW forecast stated that the pattern would shift to high lattitude blocking mid to late Jan which would be as a result of stratospheric warming - so fine thats a cause & effect forecast - but if we get high lattitude blocking but no warming then that doesnt make the forecast correct- anyway have a good one s

In this set up- is being modelled to exactly how the atmosphere is behaving from the start point at 00z or 06z- but at day 6 the net result for the NW atlantic is the same as it generally always is - IE whatever the impacts of the AAM spike isn't enough to produce a change on the atmosphere for that specific part of the world even though at the moment there may be significant impacts elsewhere- That's not to say that further down the line it may change for the better... I look forward to the projected NAO flip week 3, to add to my comment earlier ( & something I said to Lorenzo at the start of the Winter ) All the winter forecasts are based on analogues - Analogues & best fits that will hold SOME relevance going forward, however that best fit & relevance is only as good to the point where the overall starting points of the teleconnections are comparable to the original start point - IE because the planet is evolving at such a huge rate of change & because of the amount of factors that influence the dynamics of the atmosphere - what was once a useful match becomes insignificant due to being overwhelmed by something else - IE there are no analogues. 2 things punctuate the global weather ( this year specifically ) - Super El NINO - which will be the overwhelming factor for at least H1 of Winter, & for the fact that 'extremes' of weather are becoming more & more frequent. So record warmth COULD swing to record cold, or record WET could swing to record dry. but it wont be forecast.... S -

For reference in terms of what I said - there has been significant change in the models ( most notably the GFS ) which swung the cold west- all that was missing was a higher amplitude wave in the atlantic Projected GFS day 6 thurs 1pm Probable verification Upper Air projected Upper air probable verification For London then I make that a swing 8 degrees & for most 4-6 degrees. Not quite enough for the full on Cold & snow- but you would have to be Stevie wonder not to see the difference.

I think ignoring shortwaves and the ops in this setup is delusional. The ability to forecast on a global scale is therefor of great value if you can generally pinpoint the locale of the blocking highs for the winter + the phase changes + on top of that there's 'some' value in putting together a forecast for the projected phases of the -AO & -NAO then that's of 'some' use as well - but it only goes so far- & specifically to the UK becomes only a loose connection- & whats clear is no one so far has much clue about 'change' in phases - again just using reanalysis charts to try & pattern match when the stratosphere may or may not change. Anyone can do that with enough time on their hands. Interestingly though the current pattern wasn't forecast by me, you or anyone for that matter - Every single weather forecast / er continued the global very strong westerly flow well into Jan - when infact the biggest kara ridge for some years developed. It was only then when the teleconnective parameters started to react to the change & was it seized apon - IE cause & effect. Not forecast then change. The operational Models - at day 5 + 6 into 7 have NEVER suddenly produced a Greenland high - Every single one that's landed including the 2010 one has been well modelled in advance around day 7 & 8 into 9 - that's because the pattern that drives in its pretty easily spotted by both the GFS & ECM. So is there going to be a Greenland high suddenly appearing today at day 6/7 on the ECM or GFS 12z. NO. No chance. so the use of the operational & the ECM mean is not delusional today - your assessment is miles off. Even the UKMO @ 144 @ day 6 is telling us 0% chance. because the amplitude of the wave & the residual flow of the eastern seaboard means the energy is moving E or ENE - not North or or North west. The best we do here is an atlantic ridge holding the atlantic at bay for 1 day- but looking at the amplitude on the UKMO is already struggling to reach Greenland. As for again writing of the shortwave pattern - again I don't agree. ( how can you forget the December NW forecast that got smoked 2-3 years ago when the models plumped a shortwave over Norway & scuppered the block) The shortwave pattern is everything to the UK as with our size on the worlds map the UK needs only lives in a small corridor for cold & that means theres no room for variance in the track. There have been so many occasions in the last 5 years where the models have got to day 7 with a block showing cold for the UK only to resolve the shortwave pattern at day 6 & 5 to find that the cold either stops short of the UK from the east or is steered away from the UK - anyone that's been on here more than a year will know & anyone been here more than say 5 years would essentially file your comments in the bin. Shortwaves that form around / under the main block are responsible for funnelling the coldest air on one direction - but they also limit the area that the cold covers, so more concentration of cold - less coverage has been the trend for the last 5 years- You only need look at the Kara ridge to show this in action - when the super high started in the models as a clean high, only to see day 6 & 7 a shortwave get modelled to come under the base- its clear as a bell over Norway on this chart so in terms of this upcoming cold spell binning the ops is incorrect for day 6-8 as we already know there no Greenland high in the mid term, it will be a polar high & an atlantic ridge with an amplitude probably south of Greenland, meaning that at days 8 + 9 into 10 the pattern will slacken off for the UK & the atlantic will have an impact - The more circular the atlantic high the further east the milder air will reach - possibly even east of the UK, if it can be sharp enough to reach Greenland then the inflection point ( like yesterdays ECM 12z ) may send the energy more southward across Ireland brining snow- History tells us that eastward is more favoured than southward. Also again critically on something you dismiss is highly impactful to the UK for the penetration south of the cold, the depth of the cold & the speed at which its delivered..- as the modelling of the shortwaves around 144-168 from GFS V ECM although only separated by a few hundred miles are why the shortwave pattern is critical good alignment for cold - bad alignment for cold. So - in Summary, I think your post is way off the mark - both in relation to the formation of the Greenland high ( as its already toast ) & the part the shortwave pattern plays for the UK--- S

ignore the quote its keeps coming up on phone GFS ensembles have moderate support for blocking across the pole - about 5/20 ptb 7,19,20 are the best- This is the best chart since 2010 with a standing 3 wave pattern -

i call it that ( & For most its easy to understand ) to get a Greenland high ( a decent sustainable one ) we need WAA up the western side of Greenland with a large amplitude wave - when you see WAA that appears to be near vertical ( even though it isnt ) on the 2D meteociel charts you know your in business- the ECM picked this up in 2010 before the GFS & this was the chart If you look at the ECM 240 for the same area of Greenland its a very similar story - s

ECM is the best run of the winter & has a large enough amplitude of the wave in the western Atlantic to reach into the pole & beyond ( this is how 2010 started with the vertical advection ) lets keep the feet on the ground as cross polar highs are notoriously hard to forecast - linking the Atlantic high to a cross polar high needs perfect timing & phasing never the less - great to look at!

As bad as the GFS is - The ECM is at the other end of the scale with significantly better cross polar heights precluding a more significant negative AO again - as I think I mentioned yesterday - a Stella run for Scotland - with lots of snow-! some snow for the low Thursday as well s

You may want possibly reconsider the words from best so far to not quite as sh*te - whilst the anomalies may show a partial -AO they also represent a classic +NAO with negative anomalies over iceland & positive anomalies extending east into europe away from the azores - so classically mild for the UK- also the negative AO forecasts have somewhat tailed off to the mean now only showing around -2 & the clear drivers of this pattern are the + PNA ridge & the Kara high... no good for us im afraid....

Poor GFS tonight- no blocking whatsoever - everything transient- theres only 2 places we want that atlantic high to go & its already unlikley that greenland is one of its destinations - so scandi is the other locale thats even less likely - lets hope the ECM 12z is more fruitful - s

Well we shall see lets hope this doesnt land..... s

Maybe -Maybe not ... some years like 2010 etc you feel like its a matter of time before the next cold episode, this winter feels a case of not long for the next let down- we have around 5-7 days to wait now to see if anything comes of the block that develops over eastern canada - whether it can slow the jet enough to then allow for a ridge - FwIW - 18z shows a classic scandi high development- a risge thrown NNE out of the azozes settling over scandi also of note for ref is the debilt ENS has nice cold clustering near the end - days 12-15 I think most of us will take anything at the moment - just 1 air frost here winter to date is a joke..... s

So near & yet so far -.......

ECM 192 has another system travelling east across scotland in the cold air - if things go along according to the ECM the Northern part of scotland & Shetland ( maybe areas slightly further south ) could see a fair depth by this time next sunday !!

After the continued awful 12s we may as well comment on the here & now ECM 120 rain / snow & a 957 mb low - so gusts heading up to the 80 MPH mark not great for the already flooded areas- Could be a LOT of snow for the hills of scotland - especially as the cold digs back into the extreme North at 144 -

If we dont get cold on the best opportunity of the winter then it doesnt bode well for the rest of winter bearing in mind theres only really 2 areas of blocking that deliver cold for the UK - scandi & greenland - 6 weeks of winter down & the 1 & only block to the NE has failed to deliver - so if thats the run rate for the winter then winter is over - if we had lucked into cold then of course it would be a different story....

Ps look how close todays GFS is at 108

Morning all first of all happy new year well, its been a pretty ropey couple of days in the world if virtual weather - IE living 4,5,6 days in model land - for me - relating to the forecast its been good & bad news In the post the other day I mentioned changes for 2 things - the atlantic profile & the shortwave over norway - well the positive news was the energy that was predicted to exit North out of Scandi did infact correct to move westwards towards iceland & more positive heights are identified - if we look at the UKMO 72 & 96 that energy moving west did change the angle of the cold over europe to a more westerly flow - always a positive for the UK in terms if the atlantic though - the ridge wasnt sufficient or acute enough to deliver energy surging south of the UK infact the final position of the jet ended up trending to be angles ENE ( instead of ESE ) so instead of low pressures diving across the Uk they are now projected to move through the uk & will deliver next to nothing in the way of wintryness for the UK except for the scottish hills - pretty disapointing in an initial set up the promised more - in terms of future set ups like this & the fact that the UK will of course experience cold weather again we can: * look for the routes to cold for the UK & see if they manifest in the models & actually deliver * look at the models & look for the ways the potentially may develop & scupper the cold for the Uk * forecast endless mild weather & because of the general weather for the UK claim success because of it neither of the latter 2 interest me, its Winter & if we cant all enjoy a bit of the white stuff then were on the wrong forum. More rubbish weather to come - nothing for most of the populus in the next 10 days which puts us at virtually halfway house for winter 15/16 im already thinking this winter is going to be destined for the bin but hope to proved wrong... enjoy s

As expected a much changed ECM & if you like snow day 7 is full of it - inclusive of the midlands North this time from the slider.... Gone is the deep bowling ball low - S

I bet my xmas prezzies the ECM is much different tonight again the updated 12z JMA to 84 has the ridge & the arpege to 114 does as well eyes down for NAVGEM & ECM

A much changed GFS 12z which swing considerably - the cold & snowline corrects to just off the east coast as opposed to Norway so a halfway correction by the 12z run- not the most inspiring UKMO as that corrects slightly flatter .. in both scenarios at 144 the cold is Just to far east for most of the UK except for scotland & NE - this is the first GFS to run this however remember I said 12-24 hours not 6...... s