Model Output Discussion - 05/01/2016 18z onwards

[TSNWK]

3 minutes ago, Steve Murr said:

 

Yes mate it snowed all day sat although bexleyheath ( IMBY) the front fizzled a bit - where as to the SW on the downs they got 3-4 inches ( nearer 1.5/2 here )

This is a similar scenario here although perhaps not as condusive to snow - more prolonging the deep cold as its difficult to really see where the UKMO goes past 144 -

the atlantic shortwave is to accute to get into the UK but does stop the sinker - the high could respread Nw & NE so 168 is deffo still very cold but thereafter - unsure.... As no visibilty of shortwave pattern....

S

Many thanks Steve

[nick sussex]

Looking at the ECM postage stamps a real mix of solutions at T120hrs:

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016011200!!/

Theres quite a few that have a much better orientation and position of high pressure near the UK.

In terms of the pattern in the eastern USA which does impact on the troughing to the west of the UK.

MODEL EVALUATION AND PREFERENCES... MODEL GUIDANCE CONTINUES TO SHOW A LARGE AMOUNT OF SPREAD WITH THE EVOLUTION OF THE DEEP VORTEX EXPECTED TO DROP DOWN FROM CANADA AND ROTATE OVER THE UPPER GREAT LAKES THIS WEEKEND...RESULTING IN A GREAT DEAL OF UNCERTAINTY WITH THE TIMING/AMPLITUDE OF THE SHORTWAVE ENERGY LIFTING OUT OF THE SOUTHERN PLAINS AND THE EXACT TRACK/DEPTH OF ASSOCIATED SURFACE LOWS DEEPENING OVER THE OHIO VALLEY AND NEW ENGLAND COAST. THE GFS/GEFS MEAN HAVE GENERALLY BEEN SLOWER WITH SINKING THE VORTEX INTO THE UPPER MIDWEST/GREAT LAKES...WHILE THE ECMWF/ECMWF ENSEMBLE MEAN HAVE BEEN ON THE FASTER SIDE OF MODEL SPREAD. THE WPC DAY 3-7 FORECAST WAS LARGELY BASED ON ENSEMBLE MEANS/CONTINUITY TO ACCOUNT FOR THE UNCERTAINTY...WITH SLIGHTLY MORE WEIGHT TOWARDS THE ECWMF ENSEMBLE MEAN SINCE IT HAS BEEN A LITTLE MORE CONSISTENT WITH THIS FEATURE.

In terms of the ECM De Bilt ensembles, although theres a strong signal past day ten to lift temps over there still a large spread before then:

 

 

 

Edited January 12, 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 TUESDAY JAN 12TH 2016

THE CURRENT GENERAL SITUATION   Low pressure lies over the North Sea today with a strong NW flow across the UK backing Westerly and decreasing tonight as Low pressure and frontal troughs arrive from the West across the UK tomorrow.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the British Isles will lie around 1000m or 4000ft today and tomorrow with some snowfall in the form of showers on hills and mountains above around 2000-2500ft

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

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

MODELS-2 WEEK HEADLINE  Rain or wintry showers at first. Becoming colder and drier with frost and fog patches likely next week.

THE GFS JET STREAM FORECAST  The main theme of the Jet Stream today shows the Jet Stream continuing to stream East across France over several more days before it changes to flow South across the UK by the weekend and start to next week. This lasts as well for several days before the flow gradually returns to a more normal West to East flow to the North of Scotland from the middle and end to next week.

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

GFS OPERATIONAL The GFS Operational Run today shows a slow progression away from the current rather cold and unsettled weather as Low pressure slowly moves off to the East by the weekend allowing a strong ridge to cross the UK from the West with cold and frosty conditions. Then next week a slow return to less cold weather following a period of rain or snow moves slowly East over the UK followed by a return to mild SW winds, strong at times and rain at times towards the North and West in particular with some drier spells as well.

GFS CONTROL RUN The theme of the Control Run shows a similar sequence of events through the period with just small variances of timings. The main message is that the rather cold and showery conditions currently and the fine cold weekend soon gives way to Atlantic fronts next week with rain preceded by snow in places leading us into a much more changeable second half to the period with windy and mild weather with rain at times alternating with some dry and cooler conditions behind the fronts bringing the rain as High pressure to the South and Low to the North is maintained.

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

UKMO The UKMO model today is again much more robust and resolute in maintaining a cold theme across the UK well into next week as it shows the High pressure cell both further North and holding back the Atlantic fronts to the West. the resultant conditions will be cold conditions continuing across all areas with some wintry showers near eastern coasts and sharp overnight frosts developing for all inland areas. 

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

THE FAX CHARTS The Fax Charts show complex Low pressure clearing away slowly East late in the week but leaving a legacy of chilly North winds and weak troughs moving South over the UK with cold weather with wintry showers especially near coasts continuing well into the weekend.

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

GEM GEM this morning teams with the GFS theme of events across the next 10 days as the cold Northerly airflow until the weekend gives way to High pressure, cold and frosty weather over the weekend and then a slow retreat of High pressure away to the SE allows milder SW winds to strengthen across the UK with some rain largely across the North and West while the South looks likely to stay largely dry.

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

NAVGEM NAVGEM is broadly similar in theme to GEM and GFS too with the same sequence of cold North winds and then calm, cold and frosty weather slowly giving way next week to milder SW winds as the High pressure topples away to the SE.

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

ECM ECM today is unmoved in it's support to the general theme shown by the majority of output this morning although the breakdown to the eventual return of milder SW winds is a messy one and could result in a day or two of raw weather across the UK early next week with a messy mix of rain and snow around before the SW winds strengthen and push any residual cold air away by the middle and end of next week as High pressure is pulled to the SE of the UK. 

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

ECM 10 DAY MEAN The 10 day mean chart shows High pressure likely to lie to the South or SE of Southern Britain in 10 days time with milder conditions having spread to all areas. Pressure is unlikely to be very low so the South and East could be largely dry and benign but stronger SW winds across the North and West will more than likely lead to some rain at times here.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The models continue to show milder air penetrating the UK next week from the Atlantic with the exception still of UKMO.

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  and GFS at 99.4 pts respectively.  At 3 days ECM is leading with 97.5 pts to UKMO's 96.6 pts while GFS lags behind at 96.1 pts. At 5 days ECM leads with 89.6 pts to UKMO at 87.6 pts then GFS at 87.1 pts. Then at 8 Days ECM still leads at 66.5 pts over GFS's 63.5 pts. Finally at Day 10 ECM is ahead of GFS at 49.4 pts to 47.1 pts respectively. 

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 is a major stand-off in the models this morning which has now been going on for several days. The battle on the face of it is a very one sided one with the majority of all the output maintaining their stance on returning milder Atlantic SW winds across the UK from early next week. In among all this we have UKMO which shows much more resilience to any such breakdown illustrated by the rest of the output and had it been any other model other than UKMO with the exception of ECM I would more easily discount it but as it is and it's persistence and consistency in showing it's pattern I am not so sure. So dealing with the here and now first we have a rather cold and breezy period of weather still between now and the weekend to get through when some windy, rather cold and showery weather persists with some snow on the hills in the North extending to all areas for a time later in the week. Then pressure is shown to build across the UK at the weekend nudging the Northerly flow away over the North Sea and leaving the UK under High pressure with very frosty weather for a time. Then the favoured options shown by the vast majority of output shows a return to milder SW winds and rain at times, chiefly across the North and West whereas the South and East look like becoming largely dry and benign in lighter SW winds. Then as hinted at earlier we have UKMO isolated in showing High pressure further North and angled such that would hold back the Atlantic and maintain cold and frosty weather for longer and while winds remain NE in the SE some wintry showers could be maintained for longer there. It's difficult to ascertain how things would evolve longer term with UKMO as we only have access up to day 6 but using their extended outlooks issued daily I would suggest that it too would gradually fall into line with the milder theme albeit much slower to establish it across the UK than the rest shows. So a good few days of rather cold weather with showers, wintry in places then an undetermined length of period of frosty weather before a return to less cold weather in SW winds is the maintained message this morning with no real sign of anything 'winter wonderlandish' likely for many over the coming few weeks across the UK I'm afraid.

Next Update Wednesday January 13th 2016 from 09:00 

[mb018538]

At least if we do see a return to the dreaded SW'erlies in the near future, it appears we will be closer to the high pressure this time so it should prevent things being as disastrously wet as they were through December. Looks like we're pinning our hope on the UKMO being right, as the others don't want to play (snow)ball!

[Tim Bland]

Whilst discussing the reliability of the UKMO is interesting isn't the net result the same as the other models? All we are looking at here is how long the cold high lasts over the uk before the pattern flatterns and the Atlantic comes back in. We know the long term evolution of the UKMO model from the met office over night update - They say Atlantic returning by mid nxt week.  I think the high sinking into Europe and a return to zonality is inevitable here. Let's just hope Feb delivers something of interest ! 

[Nick F]

FWIW, the EC32 that updated late yesterday shows a predominantly high pressure dominated pattern in the locale of the U.K. through much of the 10 to 32 day period. Also the 00z EPS mean has a +height anomaly near the UK  days 10-15, albeit, weakening towards the end.

Be interesting to see whether or not on coming few runs GFS and EC pick up on a trend for more energy/troughing to undercut the SW side of the ridge building across the UK this weekend, as the UKMO shows early next week. Really need to see that upper trough pushing out across the Atlantic continuing to dig SE into early next week after that ridge builds north across the UK this weekend.

[carinthian]

23 hours ago, carinthian said:

Morning all. I think most on here would welcome this chart for next Sunday. A big dry up for the North and West and all with a lot of ice. Some  cold air entrenched over the UK, not only surface cold but lower uppers, particularly over SE Britain next weekend. Note the drop in heights moving westwards in Southern Europe, this should help hold back any fast sinking of the strong developing  high to the west of The British Isles. There is also evidence of a upper trough forming in the Euroland cold flow and maybe the best chance for next weekend for the SE to see snow showers.  For the rest of this week, showers or spells of sleet and snow could crop up almost anywhere, just nay impossible to pin point today, but maybe even the SW of England could have the deepest of cold flow tomorrow afternoon before the 528 dam line cover much of the Kingdom and Eire. Will try and update SE potential for next weekend after getting latest snow portal results later today. Mild here in the Eastern Alps his morning with wet snow conditions and thaw, however the boundary between mild and cold is narrow, so snow could return in a matter of hours.

 C

Morning all, massive difference between the main models this morning. The UKMO the pick for colder lovers with high pressure holding to the NE with fall of pressure to the SW. This can easily be seen on the comparison chart to yesterday. Will this be the correct chart ? Well as promised have now just spoken to our snow portal service over here about all options. I am pleased to say they have come down firmly with the UKMO option of prolonging the cold weather  for at least another 7 days including the UK and much of Europe. They cannot go much beyond that  other than what the seasonal models have produced. In fact the cold is likely to become quite intense in Central Europe by this time next week. I asked about the snow potential next Sunday for the Southeast following on from yesterdays report. Their high res snow model keeps the SE at risk of snow showers with-in the range 120 hours -144 hours.  The other feature to watch is the low now exiting Iceland, track its direction on the 850mb wind flow charts over the next 48 hours. During the period 48 hours to 96 hours its hard to mark the boundary layers between, rain , sleet or snow in the location of the British Isles, as the circulation will be a mixture of Am and Pm origin. However, the UKMO do say even snow could fall to lower levels in the south during this period, but certainly at elevation.

[Frosty.]

The ukmo 00z is another peach with the cold, frosty spell lasting well into next week. It's going to become colder everywhere with increasingly wintry ppn and snow down to modest levels as time goes on, even across the south and we will all see widespread frosts and icy patches..as for next week, there are indications we could see trough disruption as the Atlantic systems approach the UK. Enjoy this week coldies, we have waited long enough!

Edited January 12, 2016 by Frosty.

[SMU]

GFS 06 out to 66- already more incremental swings to the UKMO in terms of amplifcation-

I will post the 126 00z V the 120 06z for comparison...

s

[booferking]

Slightly more amplified this run out to 72hr small differences can make big difference if the trend continues.

[Nath]

I have seen some model disagreements over the years, but this is amazing and fascinating.   I am not discounting the UKMO being correct either.  

The most satisfying thing about this week is that mother nature can still confuse and be illusive to madkind's best technology, and I hope she always will!

[I remember Atlantic 252]

FI but surely snowy for the N midlands, even low level, as for snow here I need the 'dark blue' thicknesses

[SMU]

Upgrades continue - a net decrease of around -2c at 850 at just 102 v 108

before

after

S

[coldcomfort]

15 minutes ago, Steve Murr said:

GFS 06 out to 66- already more incremental swings to the UKMO in terms of amplifcation-

I will post the 126 00z V the 120 06z for comparison...

s

I'm confused here....I thought you didn't rate the GFS and had even less regard for it's 06 output, or have I missed something?

[northwestsnow]

Just now, coldcomfort said:

I'm confused here....I thought you didn't rate the GFS and had even less regard for it's 06 output, or have I missed something?

Not about that cc, more about the gfs moving towards the UKMO  

[coldcomfort]

1 minute ago, northwestsnow said:

Not about that cc, more about the gfs moving towards the UKMO  

Agh OK, thanks nws, tho I must say it doesn't look hugely different to me, just normal variances.

 

Edited January 12, 2016 by coldcomfort

[mickpips]

To my eyes the GFS 06Z appears to be bringing the SW'LYs in even earlier on Sunday !

[radiohead]

3 minutes ago, coldcomfort said:

I'm confused here....I thought you didn't rate the GFS and had even less regard for it's 06 output, or have I missed something?

Well the 06Z will have initial conditions 6 hours more recent than the 0Z.

[northwestsnow]

1 minute ago, coldcomfort said:

Agh OK, thanks nws.

Perhaps gfs6z pointing to a snowy breakdown

[Liam J]

6z out to T120 and still quite different to the UKMO, the GFS does bring in marginally colder 850's than the previous run.

[mountain shadow]

No point looking past here. The differences in the Western Atlantic are large.

[winterof79]

Heights to our N/E possibly building on this run?

[MP-R]

3 minutes ago, *Sub*Zero* said:

6z out to T120 and still quite different to the UKMO, the GFS does bring in marginally colder 850's than the previous run.

Really need those low heights over the Med to back westwards and prop up the high over the UK. May even bring that phantom easterly in later on. If not, the GFS' F1-speed arrival of southwesterlies may just come into fruition.

[northwestsnow]

gfs6z showing a snow event on monday as the atlantic disrupts

[swilliam]

The progression of the rain is slower and more energy going SE - also note the curve over N France. Slow progression makes a longer snow event

 

06

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