Model output discussion - 20th Feb onwards

[Man With Beard]

 

The ECM sticks with the short warm up followed by the "cold-round-the-back" scenario - the scenario that has been kicking around in the ensembles for days.

The cold pool is not dramatically cold this time but the colder versions are still out there:

The NOAA may not completely agree with this, but then again, it has changed quite a bit between the D8-14 version 3 days ago and the D6-10 version yesterday, so perhaps more changes to come:

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON MONDAY MAR 7TH 2016

THE CURRENT GENERAL SITUATION   A ridge of High pressure will gradually cross East over the UK today and tonight followed by a weakening occluded front crossing East over the West of the UK tomorrow

http://www.wetterzentrale.de/pics/Rtavn001.gif

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will remain around about the 2000ft mark for today but with mostly dry conditions away from a little showery snow over the peaks with exposure to the North. The Freezing level edges upwards towards tomorrow towards 3000ft across the South and West. 

http://www.snow-forecast.com/maps/dynamic/uk

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif

MODELS-2 WEEK HEADLINE  Becoming less cold and mostly dry but perhaps turning rather colder again later with frost at night.

THE GFS JET STREAM FORECAST  The Jet Stream has a few more days of blowing South across or just West of the UK. By soon after midweek the flow severs and turns to a West to East flow to the North of the UK as High pressure slowly builds North and NE across the UK. This then sets up a period of an anticyclonic flow to the Jet stream around the UK as High pressure lies across us. Later the flow reignites and blows West to East across the UK in more unsettled weather returning from off the Atlantic.

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS Operational Run's theme today is for the current cold Northerly flow to be completely removed by later this week as a deepening Low crossing Southern Britain midweek with some heavy rain is the precursor to a strong rise of pressure later in the week with much milder air from the Southern parts of the North Atlantic wafting up across the UK. Then High pressure establishes across Britain with some fine and dry weather with some very mild Spring sunshine across the South and East very welcome for quite some time. Then towards the end of the period pressure collapses across the UK and on this run cooler and unsettled conditions make there way down across the UK late in the period.

GFS CONTROL RUN The theme of the Control Run shows a similar evolution with High pressure taking control of the weather centreing close to the UK next weekend. Any Spring warmth may be more temporary on this run though as the High moves North and a chillier Easterly flow sets up for a time across the South. Then a fairly rapid change in the second week as High pressure declines and Low pressure re-establishes to the North and East of the UK returning us to where we have been lately with cold and showery NW winds with showers turning wintry over hills.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=144&mode=0&carte=0

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=384&mode=0&carte=0

GFS ENSEMBLE DAY 14 DATA  The GFS Clusters today have returned to a colder pack this morning as many members form a camp that say NW winds will be blowing down across the UK in two weeks time with Low pressure close by to the North and NE of Britain. Of these a small 10% pack show a full blooded and cold NE flow across the UK with deep low pressure over France.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

UKMO The UKMO model this morning to me looks less mild than previously thought totally due to the positioning of the High pressure in relation to the UK. So once Wednesdays wet and windy weather clears away High pressure ridges strongly across the South from a centre across Denmark and persists there through next weekend while the mildest SW winds affect the North and NW. With slacker variable winds over the South some night frosts could occur with dry and fairly benign daytime conditions.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts show slow changes across the UK in the coming 5 days. We still have 1 more inclement Low pressure area to endure under the rather cold conditions making Wednesday a very unpleasant wet day across the South in particular and I wouldn't be surprised to see more hill on it's Northern Flank as it clears. Then it's all about how quickly and decisively milder air from the SW engages with the rise of pressure occurs across all parts of the UK towards next weekend.

http://www.weathercharts.org/ukmomslp.htm#t120

GEM GEM this morning shows a deep low on Wednesday the last in the series of fronts and depressions that have delivered the recent spell of rather cold and changeable weather. High pressure builds in from the SW by the weekend bringing much milder and fair conditions for most of the UK. The mildness might not last long though as High pressure is sucked North and then NE to lie across Scandinavia next week allowing a feed of colder continental air to be drawn up across the UK then but still in generally dry weather with just the risk of a shower in the South and SE at the end of the period.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM shows another version of the previously shown synoptic pattern that brings early Spring warmth to the UK by and through the weekend. Enabling this is the position of High pressure close to SE England drawing up very mild SW winds across the UK with some Spring sunshine in the South.

http://www.wetterzentrale.de/pics/Rnvg1681.gif

ECM ECM today shows High pressure building up from the South towards the weekend following an inclement period of potentially wet and windy conditions on Wednesday. By the weekend pressure is High and building further across the UK with fine, milder and settled weather after a day or two of damp weather in the NW. The mild air is not shown to last long though as High pressure transfers North and NE towards Scandinavia and like GEM brings a colder ESE flow across the UK by midweek next week with potential trouble developing towards the South and SW of the UK.. 

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN The new 240hr mean Chart this morning shows High pressure anchored over the UK in 10 days indicating almost guaranteed settled and dry weather. The only differences between members is of course the resting place for the High cell determining the conditions that can be expected towards the surface in terms of temperatures and sunshine amounts.

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The trend is well set for the weather to become fine, settled and less cold from the latter end of the week with solid cross model support for High pressure to build across the UK though there is a theme developing which suggests the mildness may not last too long.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with UKMO at 99.5 pts and GFS at 99.4 pts.  At 3 days ECM is leading with 97.6 pts to UKMO's 97.0 pts while GFS lags behind at 96.2 pts. At 5 days ECM leads with 90.7 pts to UKMO at 88.5 pts and GFS at 86.2 pts. Then at 8 Days ECM has the leading spot from GFS with 65.1 pts to 60.5 pts. Finally at Day 10 GFS has the lead from ECM with a score of 47.2 pts to 46.5 pts.

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.png

MY THOUGHTS  There remains strong support for a marked rise of pressure across the UK later this week and lasting for some considerable time thereafter. In the meantime we have 1 more Low pressure cell to endure as it moves into the South of the UK by Wednesday with rain and strong winds and maybe some hill snow here and there for a time. Once passed pressure rises strongly across the UK and although a short mild and damp spell may affect the North and West in particular the theme of dry and mild weather developing for many across the UK by the weekend is a strong one. There are varying choices of the resting place for the High to position itself which has fundamental implications for the strength of the warmth and sunshine amounts that will grace our shores over the weekend and start to next week. For those thinking that this is the start of a long warm spell relative to March may be a little disappointed from this morning's output as there is growing signs that the High may be pulled North and NE of the UK next week which if verified would pull winds into the East or SE bringing less mild and possibly rather chilly conditions back across the UK though it would likely stay largely settled. If things don't decline by that method there is other output that shows High pressure slipping away and being replaced by a cold NW wind and showery theme with GFS carrying this theme supported by it's clusters and ensembles. So while taking all that into account there is a very welcome change ahead for mild and settled conditions across the UK for a time commencing from around Friday and lasting for a time before things probably turn somewhat colder again and possibly more unsettled by the end of the two week period.

Next Update Tuesday March 8th 2016 from 09:00

[feb1991blizzard]

On ‎05‎/‎03‎/‎2016 at 3:19 PM, phil nw. said:

Yes did notice the latest gefs at the end of the run-possible Scandi.trough? 

Depends on the orientation of course-the deepest cold that would still be around could still miss us and go into C./E. Europe with us on the edge of things.

Too soon to speculate yet on that for me i would rather wait for consistency in a couple more ens. runs for that one that's why i did't offer any comment in my earlier post.

 

Yes too soon and although potential cold still showing in FI, theres too many scenarios to have too much faith yet. Does anyone know if the overnight ECM EPS extended are a stonker or not yet?

[chionomaniac]

Lovely looking heart shaped high on the ECM at T+240 this morning. Has @Tamara spotted this as this used to be her profile name for exactly the reason that an omega block like this can deliver the goods. Pity that it is about 2 months too late!

 

The split of the dislaced vortex is starting to come through now in the trop blocking patterns for the second half of March following the SSW. There is an increased likelihood of a -ve NAO than at any time in the winter just gone and the UK could find itself right in the path of a strong Arctic blast once this weekends lovely warmth fades.

ECM H5 anomalies not as favourable as the GEFS but unless you can see the clusters then the solution may be obscured somewhat. GEFS suggesting increasingly strong Scandi trough with Atlantic block by day 16.

 

It is not a chase for snow that intrigues me for this month, but the intriguing synoptic trop response following the strong SSW that still continues to grow.

Edited March 7, 2016 by chionomaniac

[Frosty.]

The Ecm 00z ensemble mean becomes emphatically anticyclonic, equal to the GEFS 00z mean with high pressure centred over the UK and a very pleasant spell of early spring weather for all parts of the uk..

[knocker]

The ecm, 6-10 is very amplified with the HP over the UK pushing north towards the Pole. much like the det, run in some respects. The EPS 10-15 has the deep Atlantic trough quite diminished as expected but maintains weak ridging over the UK with the trough into NE Europe. This would give a westerly upper flow over the UK with temps not too bad. But if this broken down to individual days in the latter stages the ridging over the UK is no more and a much zonal flow is in situ bringing one suspects more unsettled weather from the Atlantic.

Given the evidence to hand major blocking does not appear to be the percentage play at the moment in the medium term but the evolution is in a state of flux and apart these comments and my previous posts the rest is way above my pay grade. And Sidney's.

[Frosty.]

Next weekend is a cracker according to the Gfs 6z with high pressure intensifying over the uk..temperatures are also higher on Friday compared to the 00z with some areas hitting the mid teens celsius which also applies to next weekend, very pleasant days with spells of sunshine and light winds but nights look chilly under clear skies with a touch of ground frost and some patchy mist and fog but for those of us who want a complete change, your wish will soon be granted!

[mulzy]

9 days out on the 6z GFS (usual caveats apply ofc) but this is an interesting chart!

 

Edited March 7, 2016 by mulzy

[Singularity]

Heights over Svalbard are notably higher from as early as +144, and this has a big impact down the line. Essentially picking up on ECM's idea, but with the LP under the block aligning such as to reach further east and bring considerably more in the way of cold air toward the UK.

This is the sort of thing that I have become concerned about. Let's see just how far those temperatures drop...

[chionomaniac]

1 hour ago, chionomaniac said:

Lovely looking heart shaped high on the ECM at T+240 this morning. Has @Tamara spotted this as this used to be her profile name for exactly the reason that an omega block like this can deliver the goods. Pity that it is about 2 months too late!

 

The split of the dislaced vortex is starting to come through now in the trop blocking patterns for the second half of March following the SSW. There is an increased likelihood of a -ve NAO than at any time in the winter just gone and the UK could find itself right in the path of a strong Arctic blast once this weekends lovely warmth fades.

ECM H5 anomalies not as favourable as the GEFS but unless you can see the clusters then the solution may be obscured somewhat. GEFS suggesting increasingly strong Scandi trough with Atlantic block by day 16.

 

It is not a chase for snow that intrigues me for this month, but the intriguing synoptic trop response following the strong SSW that still continues to grow.

LOL something like this :Classic trop response to split SSW 

 

Edited March 7, 2016 by chionomaniac

[feb1991blizzard]

20 minutes ago, Frosty. said:

Next weekend is a cracker according to the Gfs 6z

 

Yes, look how its orientating, not a million miles away from a really potent blast - last chance saloon.

 

A bit further North and its really game on!!!

 

Here comes another go from the North, not full on retrogression but a few tweaks.

 

That small low to the SW of Iceland scuppers us else it would be a brutal Northerly.

Edited March 7, 2016 by feb1991blizzard

[Skiwi1]

Within 30 hours temperatures go from the mid teens to sub -10 850s being introduced according to the gfs 6z. It would be a awfully cold shock if it verified

 

[Singularity]

 

Very low dew points with this airmass, as low as -6*C throughout Wednesday. Classic 'lake effect' snow off the North Sea - 5 to 6*C air temps not an issue with such low dew points, though the dryness of the air limits precip. rates.

Not to be taken at face value of course, but it goes to show what's possible by mid-month. Usual caveats apply but this fits very well with recent trends and expected strat. forcing, as Chiono has already outlined.

Also look at that deep low heading into Siberia. This has been a consistent feature of recent model output from most models, and should export an even colder airmass from the high Arctic into Scandinavia with a considerable threat to the UK as the pattern slowly retrogresses, this too well signaled in the stratosphere. The GFS 00z run was a very fast example of this - so much so that the cold had already come and gone by the end of the run -  but the 06z is slower again and more like I'm expecting to see.

 

I know it's not what a lot of people want to see in the second half of March, particularly farmers for example, but I can't resist getting my 'epic blocked charts' fix having waited a whole winter with little in the way of supply;

Omega Block in all its glory.

[Man With Beard]

1 hour ago, chionomaniac said:

Lovely looking heart shaped high on the ECM at T+240 this morning. Has @Tamara spotted this as this used to be her profile name for exactly the reason that an omega block like this can deliver the goods. Pity that it is about 2 months too late!

 

The split of the dislaced vortex is starting to come through now in the trop blocking patterns for the second half of March following the SSW. There is an increased likelihood of a -ve NAO than at any time in the winter just gone and the UK could find itself right in the path of a strong Arctic blast once this weekends lovely warmth fades.

ECM H5 anomalies not as favourable as the GEFS but unless you can see the clusters then the solution may be obscured somewhat. GEFS suggesting increasingly strong Scandi trough with Atlantic block by day 16.

 

It is not a chase for snow that intrigues me for this month, but the intriguing synoptic trop response following the strong SSW that still continues to grow.

Indeed, but if the pieces of the jigsaw fall into place like they do on the GFS 06Z, then it would be the least marginal snow event of the year for southern areas. It is a Kent Clipper deluxe. Nice to see the "potential" of the past few days now showing on the op runs. Such a long time away though. Best to enjoy the early season "warmth" over the weekend and see what evolves.

[bobbydog]

-10c uppers well into eastern britain??!!

persistent  snow???!!

well, after the mildest winter since the dinosaurs roamed the earth, that will probably happen!!

[feb1991blizzard]

3 minutes ago, bobbydog said:

-10c uppers well into eastern britain??!!

persistent  snow???!!

well, after the mildest winter since the dinosaurs roamed the earth, that will probably happen!!

A bit further North and that's a pasting for the SE and London, no support from Met Office though.

[bobbydog]

5 minutes ago, feb1991blizzard said:

A bit further North and that's a pasting for the SE and London, no support from Met Office though.

not sure though- their further outlook is a nod towards what we can see in the models.... 

[feb1991blizzard]

Just now, bobbydog said:

not sure though- their further outlook is a nod towards what we can see in the models.... 

Theres a timing issue though, the mention of below average isn't in the 6-15, the GFS 6z blasts it within 10 days, lets see what the ensembles say.

[bobbydog]

3 minutes ago, feb1991blizzard said:

Theres a timing issue though, the mention of below average isn't in the 6-15, the GFS 6z blasts it within 10 days, lets see what the ensembles say.

it is in the latest update issued an hour ago...

[feb1991blizzard]

A big cold pool being fired from the Arctic into continental Europe on a lot of GEFS 6z members

[Frosty.]

If any of my fellow coldies think I've gone all mild and mushy with my comments regarding the warmer anticyclonic spell at the end of this week and into next week, rest assured I'm still the same Frosty who can cold ramp with the best of them if there is something worthy of it and the low res of the Gfs 6z certainly looks peachy.

[Nouska]

1 hour ago, feb1991blizzard said:

A bit further North and that's a pasting for the SE and London, no support from Met Office though.

 I think there will be plenty of support from the law of Sod....

You just know this is going to happen after all of nature has been fooled into thinking the season is right for breeding and the fruit trees have produced their blossom.

[mushymanrob]

3 hours ago, Man With Beard said:

The NOAA may not completely agree with this, but then again,it has changed quite a bit between the D8-14 version 3 days ago and the D6-10 version yesterday, so perhaps more changes to come:

sorry old chap, i dont agree with that satatement, these charts have been most consistent now for several days, of course there has been tweeks but youd expect that in an ever changing atmosphere, but no more that id expect.

they are a very long way from supporting these fi cold charts, which have a habit of modifying greatly - they have done so every time such cold charts are shown in fi this whole past 5 months.

i have no idea what day 16 might bring, or the second half of this month , ill stick with the noaa's, when they show something - ill believe it

[David Morse]

The GFS has been flip-flopping in the FI between a very cold scenario for western Europe and very mild, but the NOAA 500mb anomalies keep the HP over the Northern UK which means we may not see the cold here, but its looking more likely that Europe will have an icy blast.

[Nouska]

28 minutes ago, mushymanrob said:

sorry old chap, i dont agree with that satatement, these charts have been most consistent now for several days, of course there has been tweeks but youd expect that in an ever changing atmosphere, but no more that id expect.

they are a very long way from supporting these fi cold charts, which have a habit of modifying greatly - they have done so every time such cold charts are shown in fi this whole past 5 months.

i have no idea what day 16 might bring, or the second half of this month , ill stick with the noaa's, when they show something - ill believe it

Signs in the 8-14 day chart of the high moving north and low heights moving into Iberia from the NE. If the pattern is in retrogression mode, maybe not so easily identified on the NH section the NOAA chart shows.

The analogue chart, centred day 11 - some cold March CET figures in the years featured.

 

Edited March 7, 2016 by Nouska