SMU

ECM 144 - azores low crushed - it has no chance.... atlantic profile building nice S

120 UKMO much more solid northerly flow with embedded troughs s

Meanwhile a stella start to the UKMO perfect allignment for that low.... s

Ok if you open up the pic & look at the NE states of the US you will see a 'bump' developing in the flow ( follow that on the model from 120-168) & that combined with the azores / atlantic ridging is your greenland high... basically for everyone - If that bump lands its almost like backing a dead cert- like having phil taylor on double 16 with the other player still on 401 .... I dead cert to win .... the dead cert is if that bump verifies day 5 then cold locks into NW europe day 6/7 to day 11 at least so the ensemble mean at 228-240 today is Very reflective of the expected pattern & unlikely to change to much overall- AO projection is -5 NAO projection is -3 i am going to look at the NAO data as it could be record breaking..... s

Ignoring the interun detail & the fact that the GfS is now touting the -10c isotherm all the way into England this is the critical chart - The secondary ridge over NE US at just 120.... nearly heading into the safety zone..... s

ECM extended superb - also those keen eyed spot that the op was a mild outlier at day 8 & 9 indicating that low was probably to deep over the UK day 7- s

As we wait the ECM a scan of the ensembles reveals * GFS control - probably the most sustainable cold spell in the UK since 1986 - with the UK in the grip of winter from day 5 out to day 16 with a snowstorm in the south & the North already under snowcover frozen solid - Also ZERO sign of pattern relaxation with the cut off greenland high still very strong .... * GFS mean all the way out to day 16 paints a negative AO ( wheres IDO !) & the mean is down to -2 to -4 over the UK still - however if the pattern actually verifies like that then then uppers would be colder.... its all about that reridging up over canada & up in the atlantic at day 6 & 7 - nothing else really matters other than that because if it does the cold has only 1 place to go - NW Europe... S

morning All stella overnight GFS & UKMO - both have the reamplification at 144 over the states delivering the super high over GH a slight chink with the evolution - day 6 sees the cold held over the north as winds hold westerly but this will sink south post that as the force of the jet will drive it that way- S

Nice little corrections early on the 18z * more southward movement in the breakaway lows over the UK at 72 * better amplitude & angle of WAA up eastern canada at 72.... could this be a double cobra night...- this is uber rare- only seen on real special weather occasions....

Man with beard the milder ones will be the low at 168 taking a more westerly route & being slightly deeper allowing a more southerly feed ahead of it ( for a time ) into the south - before moving away east again if anyone wants to see how the ECM develops post 240 you have a small window in last nights JMA - all that happens is the eastern end of the High ( towards russia ) sinks a tad squeezing the deeper cold SW ( a la 2010) & the heights lower increasing instabilty also of note is 10/11c SSTs in the north sea- overlay that with a -10c unstable NE flow & a 21c thermal gradient will = huge snow clouds but lets not get ahead ourselves - the vertical advection at day 8 is all we need -if it does the rest will come guarenteed .... S

Thanks WIBs i cannot wait for the ECM debilt ensembles diagonal line down to -5 maxima !! can the ECM verify ? Well we need only look in one place at day 8 - thats at the vertical advection if that arrives then 100% ( not 99 ) the rest will follow as its one big reverse circulation.. whos got the ECM day 10 AO? -6 i would say... can we break the record?....... adios till 930

BOOM CORBRA LOCKDOWN ADD 7 days to cold post that - Mild air do not pass go do not collect £200 s

You can come out now - ECM is safe !! also - I dont want to tempt fete - but ECM 192 has the same x2 lows seperation & the same vertical advection ( almost ) as November 2010 Remember the greenland High post - the best of them come from Highs ridging & retrograding together.. one to watch at 216 & 244 - it could be the ECM cobra run.... I feel a modeltracker coming on lol s

Little to Add other that the ECM in tandem with the UKMO 500mb profile brings in a large pool of -8c uppers at 144 across england with a patch of -9 over wales thickness around 520 & low heights = snow watch to the NW at 168 for a band of snow moving SE S

Hi neil for lowland UK - any easterly component will be a bonus !!! s

Updated AO suite from the 00z EPIC a la 2009 & 2010 s

Morning - no change from me today, the image I used last night from the 6 day mean still stands as where I think we will land ( courtesy of NAVGEM ) a nice wedge of high pressure towards greenland but the all important 552 line not making it - however if people remember the Greenland High post last night - Nearly All examples on offer of a cut off greenland high have come from High pressure forcing north from the azores- The comments I certainly tried to put across was that round 1 wasnt enough but round 2 - a day or so later may have energy to get there- Well the late models last night & indeed the early models today ( excluding the EC DET - which appears to be to progressive ) a trend positive towards this next key phase in getting our 552 line into greeny indeed the 06z mean portrays exactly what we want to see - the azores heights forcing North & bludgening the jet along with it- as above.... The cherry on the Mr kipling cake is the arctic high which if we get phasing will try to force the pattern more East to west ( like the JMA last night ) so thus far is a great day - 9/10 S

Cracking overnight runs & at day 8/9 - A possible surge of heights North into greenland aided by 'push' from pressure out of the azores into the already well established atlantic high ( GFS control at 204-228 et 'al ) UKMO sticking to its guns - but out of its fails lets hope this is the one that verifies as its on a par with last nights JMA - very similar to the above control run & also feeding into the arctic high all at just 5-6 days away !!!! S

I will just add this on the discussion from earlier - these are the dates quoted as the template period 17th - 7th jan/feb 83 This is the NAO for these dates There isnt much interest there with a low value of -0.6 but a higher peak of positive NAO at +1.34 so these dates that are touted - do not seem very significant in terms of metrics - there was an atlantic ridge early feb but no classic -NAO again if someone is citing these dates surely factually they would add credibilty to the forecast?........ S

Maybe - but it doesnt alltogether read like that as citing the models to the 20th indicates it runs along the same dateline anyway bed beckons -

It may appear like that - but there is a difference - I posted what I thought would happen across a specific timeframe - around 2 -3 days in the future & left it at that - it didnt quite go to plan & I took away the info I need- what im referring to in the post above is its ok to drop into the forum & state that this magical period of weather is going to appear around the 23rd of january due to these significant 'background' Global teleconnective signals - all of which I highlight are global signals not local - then just 12 hours later after what must be a spec of ink on the data thats updated on these global signals - the date has now suddenly shifted to the 17th - The specific trigger event being touted - is now suddenly spotted in the models - but of course had no mention earlier... so forgive me if im a little cynical as to the 'massaging' of dates around a forcast especially when the lead in period ( coincidentally not forecast by anyone who follow said global signals ) is quite condusive to possible blocking .... at the end of the day though like I said I care not whether people listen or ignore - thats my opinion & if you or others dont agree then fair enough. If it lands great - if not It doesnt matter either way anyway - just seems suspiciously massaged tonight to suit current modelling trends.... have a good one S Ps as for the met office they know that putting a specific date on a weather event nearly 3 weeks away is never going to happen As much as you get is the comments from Ian on the seasonal models -

Just to clarify ( & it may be that im being overly fussy ) seeing as this is a public forum - Saturday you posted saying the key was quote [ classical -NAO 25th & 26th Jan] then this morning it was the 23rd - now this evening its the 17th - 7th of Feb For this magical period - if your projection is focussed on an event occuring on the 20th triggering -NAO on the 23rd - whats the excitment for the 6 days proceeding that - whatever it is is a long 6 days to happen.... take this whatever way you like - but are you just plucking dates out inline with how the models may now develop seeing as the 17th ( all of sudden ) seems to coincide with what the means project to be the second bite of the cherry.... in 1 day of modelling an adjustment of 6 days in your comments..... anyone else would be accused of selective thinking...

So what to make of it all tonight many will be thinking - This from the aptly accurate NAVGEM ( more accurate than most for this week ) is the middle ground ridge- my 'best fit' run for the super ensemble mean tonight- No greenland high but enough to get a small wedge in there to slow the jet.... its pretty identical to the UKMO@ 144 ( again just like this week ) both models were a smidge over amplified -so that just to factor in.... S

Er the clue is the sea & how the advection process takes place - true cold air advection upper air movement is driven south by large High pressures over greenland ushering out south the deep cold off the greenland shelf - where as atlantic ridges & transient northerlies from Iceland or just south of greenland dont start that cold- as they have been slightly mixed by warmer maritime air The maximum cold air on tap for the UK in terms of a Northerly is about -15 for in Scotland & -12/-13 modified into the UK as long as driven south quite fast, if the process is slower maybe -10c without a High pressure the air starting around -10 to -13 over iceland will already be moderated over the sea track up to -8s for scotland - hence the -5/-6c values over England- If you take the Means of the models tonight -8/-9 into Scotland & -5/-6 to southern UK sounds about right- its just the UKMO that lucks into the original cold pool over Scandi to sweep in -10s id say for absolute coldest 850 temps for the Uk we could get is circa -20 to maybe -22c it would require perfection in terms of synoptics from start to finish- the coldest chart I have seen from the archives is -19c on 2 occasions- 1 was 12 jan 1987.... S

Im afraid that ^^ second tweet cannot be said with any degree of certainty... its a case of finely balanced on the hedge tonight .... enough evidence to suggest that based on history theres a chance it will go either way but probabilty wise favours the milder scenario ( again based in statistics & uks law of sod averages ) i duly note the ECM op was milder for debilt at day 9 & 1 suggesting a slightly to flat a pattern.... s