Model Output Discussions 18z 31/01/2016

[Man With Beard]

Just woken up from this bizarre dream in which the ECM backtracked to follow a colder GFS pattern for the second time in a week, changing its uppers from +4C to -8C in the process and rain to snow at T144/T168

But it was only a dream. That doesn't happen, does it?

[bobbydog]

whats this?-

scandi highs?.... easterlies?.... widespread snow?.... in winter?.... who would have thought it?....

even the ECM having a little think about it....

[bluearmy]

Almost a classic channel low this weekend and we manage to deliver diddly squat from it re the white stuff (away from elevation)

the disruption later next week is more interesting as the air ahead is cold - the ECM run gets it as far east as  Wales. Previous form says that's going to be further west as the ridge holds firmer than the models predict. 

how we can be struggling to see widespread snowfall from this set up in February is just ridiculous. The PFJ just too strong to allow some amplification to get cold enough air far enough South.

[joggs]

Yes and next week's slider will most probably be diluted,has as been the form this winter.It just goes to show no matter what the models show,everything has got to be absolutely spot on re  for snow and cold in the UK nearly all the time.Mo outlook still not that inspiring.

Been realistic here.If people want to decorate it up,so be it.

Edited February 11, 2016 by joggs

[terrier]

Think model fatigue has set in for a lot of people to be honest. Yes the gfs and ecm show colder conditions next week with some scattered wintry showers in coastal areas. But snowmaggedon and deep freeze it is not. Personally high pressure setting up throughout the model output isn't a bad thing and will allow areas to dry out. 

[Frosty.]

15 minutes ago, joggs said:

 

Been realistic here.If people want to decorate it up,so be it.

Time will tell, Steve murr says they are excellent runs this morning

[Bristawl Si]

23 minutes ago, joggs said:

Yes and next week's slider will most probably be diluted,has as been the form this winter.It just goes to show no matter what the models show,everything has got to be absolutely spot on re  for snow and cold in the UK nearly all the time.Mo outlook still not that inspiring.

Been realistic here.If people want to decorate it up,so be it.

Agreed.

2 days ago the model runs were showing much better snow prospects for the next few days (Tomorrow and into the w/e).

Now it's all about one week from now.

I'm firmly in the "I'll believe it when i see it!" camp.

Edited February 11, 2016 by Bristle boy

[Singularity]

So this weekend's frontal snow potential is almost dead. I say almost because ARPEGE still draws cold air in fast and strongly enough to produce some snow across the far SW on Sunday - but that's pretty much all I can find now. Basically the first system on Friday doesn't get far enough east to draw some cold air in from the east prior to its decay. So the flow barely deviates from one off the Atlantic ahead of the Channel Low.

It's all about what happens as the cold comes in along the N. flank of the low now, which may be summed up as some snow showers for eastern parts in particular, just the small chance of some interaction with a dissipating disturbance across the far SW to produce snow there, and then the potential for a more organised feature in the NE flow Monday, though this currently lacks much model support.

 

Needless to say, the midweek potential has become a far more interesting prospect now that ECM has managed to produce a trough disruption and slider low combination despite still having that secondary low bombing out E then NE of Iceland. That's a strong shout for such an event to happen, though we can't be at all sure that it will actually be across the UK when it comes around. As Steve Murr has implied, we could find ourselves high and dry - but cold, perhaps very cold at night. Speaking of which, the ECM 00z for Thu/Fri following the snow event and with such light winds would bring some seriously low overnight minima.

Beyond all that, who's to say future troughs won't disrupt as well? With a strong enough MJO response, it's certainly possible. It'll help if ECM/UKMO's secondary feature going E/NE of Iceland turns out to be a red herring. Such would be quite the victory for GFS though!

Edited February 11, 2016 by Singularity

[Polar Maritime]

This mornings snow risk for the weekend from the GFS.

As others have put, Good runs this morning for extending the cold with an Easterly type flow around the 20th.

Edited February 11, 2016 by Polar Maritime

[Weather-history]

3rd February 1990: a runner low ran through the Channel, gave a heavy wet snowfall to parts of the south

Just some food for thought....

[nick sussex]

Some very good synoptics on show this morning but frustrating that these aren't matched by the weather on the ground in the earlier timeframe.

Aside from my irritation at that it looks like another climbdown from the ECM which has now failed twice within one week. That is very rare to see it do this, if it was on the Stock Market there'd be a mass sell off and heads would roll at boardroom level!

Whats quite unusual is that the troughing to the nw has some decent 850's quite far se in terms of cold however these won't be as cold as similar values from the ne so we really want any Atlantic incursion to graze the UK producing some frontal snow but not making too much progress eastwards.

The GFS does have much more potential going forward as it builds a link between the Scandi ridge and Arctic ridge and so  theres more trough disruption and less energy spilling over the top.

Edited February 11, 2016 by nick sussex

[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 THURSDAY FEB 11TH 2016

THE CURRENT GENERAL SITUATION  A Slack West or SW flow lies across the UK with a weakening trough slipping South over Scotland and a Low pressure area slipping SE towards Northern France tonight and tomorrow with a strengthening Easterly flow over the North by then.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the British Isles remains at or around 1500ft across the North of the UK and nearer to 4000ft across Southern England. Some snow showers may occur over the mountains of Wales North England and Scotland over the next 24-48hrs.

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

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

MODELS-2 WEEK HEADLINE  Mostly unsettled with rain or showers. Fluctuating temperatures with some snow at times over higher ground especially in the South at the weekend.

THE GFS JET STREAM FORECAST  The Jet Stream is blowing due east to the South of the UK today. It maintains this position for several more days before the flow splits next week with one arm under a deep trough to the South and a weaker arm going North of the UK. This pattern then persists for some time before towards the end of the run the flow becomes more defined in a West to East flow across the UK at the term of the run.

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

GFS OPERATIONAL The GFS Operational Run today shows benign conditions over the next few days as it stays rather chilly with a few showers. Over the weekend the South sees rain as Low pressure slides ESE across Southern Britain with some of this turning to snow as it engages developing cold East and then North winds across the UK by early next week. Following this a period of cold, clear and frosty weather under a strong ridge of High pressure becomes displaced by further cloudy and rainy weather coming in from the West later next week. This develops a battle with the increasingly high Scandinavian Pressure and disrupts the troughs away SE and again producing the risk of colder weather with some snow for some. It's then not until towards the end of the second week that Westerly winds finally take command in bringing milder winds with rain at times especially across the North and West

GFS CONTROL RUN The theme of the Control Run again largely follows the theme of the Operational Run with the weather pattern finally changing next week as the South in particular comes under and maintains the influence of High pressure by then to the East with any fronts moving in from the West weakening and disrupting SE as pressure builds back across the UK. On this run too it's not until the end of the second week that wet and windy Atlantic Low pressure moves across all areas from the West. 

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 all support High pressure lying just to the South or SW of the UK in 14 days. 15% of these support a cold North or NW flow as a result with cold conditions and showers as a result. Another 15% show High pressure close to the SE with much milder air for many with 70% showing High pressure to the SW with most of the unsettled Westerly winds affecting the North more than down here in the South.

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 shows Sunday and Monday being very cold across the UK with wintry showers near windward coasts of the North and East following Saturday's wet and windy conditions with snow on hills. Then as a strong High pressure ridge slips SE to lie across the South by midweek at the same time as milder SW winds re-establish across the North and West with some rain at times. The fine weather does look like it could hang on rather longer across the far South and East into late next week.

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

THE FAX CHARTS The Fax Charts today illustrate the difficult task that the models are having in the positioning of the Low pressure area expected to cross SW and South Britain at the weekend. This morning charts have adjusted the centre of Low pressure very close to the South coast before it gently moves away East into Europe early next week. Rain and sleet as a result in the South should slowly clear SE by Monday with a cold North or NE flow bringing wintry showers to the North and East for a time early next week.

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

GEM GEM today offers a much more straightforward evolution of high pressure sliding SE across the UK after this weekends Low complex moves away SE by early next week. The wind, rain, sleet and cold weather will be replaced later next week by milder Westerly winds with some rain at times especially in the North by the second weekend.

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

NAVGEM NAVGEM takes a much more complex route as High pressure having moved it's way SE across the UK early next week remains strong and influential to the East of the UK later delaying the progress of milder SW winds and in fact reversing the theme back towards colder and still somewhat unsettled weather across the UK as we lie under shallow Low pressure by the end of next week as a result of disrupting Low pressure around an Atlantic trough soon after midweek

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

ECM ECM also delays the milder weather reaching the UK next week as like NAVGEM it disrupts the trough that would otherwise bring milder Westerly winds and no doubt giving a day or two of raw, cloudy weather with a little rain instead before the Westerly flow eventually takes hold across the UK proper late next week with wind and rain spreading through all areas at times by the end of the run.

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

ECM 10 DAY MEAN The 10 day mean chart today has taken a marked turn to bringing the Jet flow further North than has been shown in recent days with a North/South split in conditions in the weather looking more likely. So in 10 days I would suggest the greatest chance being that ECM thinks we will lie under a milder Westerly flow with rain at times chiefly over the North but to all areas at times

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The overall message is a little mixed but with the theme of milder Westerly winds in 10 days following a messy period when milder air may be delayed for a time through midweek next week being the main disagreements behind today's output.

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 97.7 pts to UKMO's 97.1 pts while GFS lags behind at 96.6 pts. At 5 days ECM leads with 91.3 pts to UKMO at 89.3 pts and GFS at 88.5 pts. Then at 8 Days ECM has the leading spot from GFS with 67.5 pts to 64.4 pts. Finally at Day 10 GFS leads today at 49.2 pts to ECM's 48.2 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   The most complex part of today's output is the way each model handles the complex situation of the Low pressure areas slipping across the South of the UK and the way they remove this away early next week with a period of cold North winds and the eventual High pressure ridge which follows with very cold frosty air. This period as it stands currently shows rain most likely in the South with a messy mix of rain and snow over Wales and the Midlands before all areas turn bright, frosty and cold with some snow showers for a day or two near Northern and Eastern windward coasts early next week. There is then some further disagreements between the models as to how they remove that High pressure away to the SE and East as the milder and stronger Westerly winds moving down across the UK from midweek. Some output shows a strong build of pressure being maintained to the East which could prevent much progress of any milder winds with even the chance from some output suggesting further trough disruption late next week delaying the progress of milder air and resulting in a couple more cold and raw days before it seems a unison message towards the end of the forecast period that mild westerly winds win out. So a very complex set-up this morning none of which show anything particularly dramatic anywhere but could result in subtle differences weather and temperature wise day to day dependant upon which way the dice falls throughout the period and particularly later next week.       

Next Update Friday February 12th 2016 from 09:00

[johnholmes]

An interesting statistic from the statistics Gibby shows above is this.

GFS has for 4 days now outscored ECMWF in the 10 day statistics. I can never recall this happening before?

 

Picking up on the synoptic outputs over the last couple of runs, overall showing a return of milder weather in the 10 day time scale. If it does happen then the synoptic charts will have another feather in their cap over the anomaly charts, quite a rare achievement. All 3 anomaly charts that I use every day show the 500mb ridge in the Atlantic and a fairly marked trough east of this from over/just east of the Uk into Europe and the Mediterranean.

Edited February 11, 2016 by johnholmes

[Ben Lewis]

48 minutes ago, terrier said:

Think model fatigue has set in for a lot of people to be honest. Yes the gfs and ecm show colder conditions next week with some scattered wintry showers in coastal areas. But snowmaggedon and deep freeze it is not. Personally high pressure setting up throughout the model output isn't a bad thing and will allow areas to dry out. 

I completely agree, very hard to even get remotely upbeat about a chart thats 7 days away. The form this winter has been to downplay any potential cold, let alone snow. Only 3 days ago was there some fairly good support from the models that tomorrows and Saturdays slider may deliver (and was even backed by BBC weatherman John Hammond) Of course thats now disappeared off the face of the earth, to be restricted to tops of welsh/Derbyshire hills at best.

Lets hope the models continue with the theme of delivering potential Snow next week. Although I have a feeling that will become diddly squat as well.

[nick sussex]

Just now, johnholmes said:

An interesting statistic from the statistics Gibby shows above is this.

GFS has for 4 days now outscored ECMWF in the 10 day statistics. I can never recall this happening before?

Yes I just saw that. Very unusual and you're right I can't remember the last time that happened. If you add on the problems it had earlier in the week and todays backtrack the ECM is in danger of losing its no 1 status. It might just be one of those bad weeks that all models can have from time to time.

[Frosty.]

The Ecm 00z really is a peach of a run if you like cold weather..and I really love cold weather! There would be plenty of frosts, some severe and some of us would see wintry showers and snow at times..this would make a very nice change from what we have endured for much of this winter!

[snowice]

18 minutes ago, nick sussex said:

Yes I just saw that. Very unusual and you're right I can't remember the last time that happened. If you add on the problems it had earlier in the week and todays backtrack the ECM is in danger of losing its no 1 status. It might just be one of those bad weeks that all models can have from time to time.

And this week's new number 1 is 

GFS TOP OF THE POPS 

[Alexis]

Does anyone know the mean wind directions for winter months? I'm sure easterly winds are more common in February and March than any earlier. I know NW winds are more common in March than any other month.

[SMU]

A much improved 06z run in short - medium term

The flow allignment between 60 & 84 is more Easterly - with less mixing & the slider low at 48 on a more southerly route-

a very good run for wales as potentially a bit of snow sat -

Perhaps even some wintry / snow flurries in the ESE sun-

all setting up to be a very cold run-

T84

s

[Polar Maritime]

A cold start to the new week continues to show from the 6z.

Edited February 11, 2016 by Polar Maritime

[Timmytour]

43 minutes ago, snowice said:

And this week's new number 1 is 

GFS TOP OF THE POPS 

It would be nice to say that, having been at No.1, the ECM was now sliding.....!

Edited February 11, 2016 by Timmytour

[Chris101]

Gfs 06z has -5 850's reaching my region a lot faster than previous, any showers on the back of Saturdays slider could be much more wintry by Sunday morning.

A small area of -10 air down to the SE corner by 120, that with SST's would hopefully bring the shower trains as it moves down.

[Nouska]

The MJO influence in action?

March last year. weather pattern on the 15th 

This year, projected path of MJO      

leads to this in the GFS 00Z run                 

 

 

[Lukesluckybunch]

Could somone please give me a rough idea of what -6uppers would represent in terms of normal temperatures c? I mean would it be like 4/5c slightly milder ,or colder?

[Paul_1978]

17 minutes ago, Nouska said:

The MJO influence in action?

March last year. weather pattern on the 15th 

This year, projected path of MJO      

leads to this in the GFS 00Z run                 

 

 

But not on the 06z unfortunately which has less of an easterly influence than the 00z :-(