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
Martin G
Kilmersdon Radstock Bath Somerset