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 APR 14TH 2016
THE CURRENT GENERAL SITUATION Low pressure down to the SW of the UK will begin to move NE towards the English Channel tonight accompanied by an occluded front which will move North over Southern England later. Another front will move South over Scotland tonight with very much colder air moving South behind it towards England and Wales over the weekend.
http://www.wetterzentrale.de/pics/Rtavn001.gif
CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The upper air temperatures are now in the range of 3000ft-5000ft across the UK currently with the pattern of the lowest uppers of 3000ft across the North lowering further to under 2000ft in a few days time and these very low uppers moving down across all of the UK over the weekend with snowfall a risk for a time over higher ground even in the South.
http://www.snow-forecast.com/maps/dynamic/uk
http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif
MODELS-2 WEEK HEADLINE Slowly becoming drier and brighter from the weekend but with the risk of cool nights and some frost for a time next week. Perhaps more showers again later.
THE GFS JET STREAM FORECAST The Jet Stream pattern will slowly change over the coming days as the steep trough in the flow weakening and simplifying as the main arm of the flow is pulled further South with the UK lying in a much slacker North to South drift for a time. Then later next week it looks like the trough could realign across the UK as Low pressure to the South moves back towards the South of the UK for a time.
http://www.netweather.tv/index.cgi?action=jetstream
GFS OPERATIONAL The GFS Operational Run today shows the current showery flow across the South with low pressure to the SW give way over the weekend to colder High pressure feeding in from the NW. This then sinks down across the South and away to the SE next week as Low pressure and showery conditions return later. However, changeable is a good term to use because High pressure is shown to return across the UK later and this time it could be rather warmer with light winds from the SE and some pleasant Spring weather towards the end of the period.
GFS CONTROL RUN The GFS Control Run is somewhat different in the way of maintaining the next week unsettled phase a little longer spliced by higher pressure later this weekend especially in the South whereas later in the run the theme towards warmer and drier conditions again across the South in particular is brought about by rising pressure over nearby Europe and winds backing towards a warm Southerly at the end of the run.
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 still show a real mixed bag of options with the biggest share of the pack keeping Low pressure in control either just to the East or SE of the UK. in balance though there is some High pressure shown too with a 20% group in contrast putting High pressure close to the SE so confidence in long term predictions remain low.
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 High pressure developing across the UK late in the weekend and start to next week following the expulsion of Low pressure away from the East of the UK on Saturday. This will bring fine and chilly weather with frost at night for a while before warmer SE winds develop in response to High pressure moving away to the East and possibly spelling a return to more showery conditions again from the SW by midweek next week.
http://www.wetterzentrale.de/pics/Rukm1441.gif
THE FAX CHARTS The Fax Charts show the transition from unsettled and showery weather to cooler and High pressure based conditions later in the weekend and start to next week. Some weak troughs across the North early next week could cloud things over there with some light rain at times.
http://www.weathercharts.org/ukmomslp.htm#t120
GEM GEM today shows High pressure building across the South of the UK later in the weekend with a weak westerly flow for a time across the North. The current showery theme will dissolve over the weekend with cool and fair conditions. Then next week High pressure migrates North and showery weather could return from Iberia across the South and later east too as High pressure finally moves out into the Atlantic and setup another cool and showery flow across the South and East with the best weather then in the North and west while staying chilly everywhere.
http://www.wetterzentrale.de/pics/Rgem2401.gif
NAVGEM NAVGEM also shows the same build of pressure at the weekend slowly giving away again by the middle of next week from the South as showery Low pressure from both the South and North regain control of the weather over the UK by this time next week.
http://www.wetterzentrale.de/pics/Rnvg1681.gif
ECM ECM today looks a bit like GEM as it jostles High pressure around the UK over the latter half of the weekend and start to next week before Low pressure from the South returns warmer but showery air north across Britain midweek leading on to High pressure drawn out into the Atlantic later with a chilly and showery NE flow developing then across the South and East while dry but cool conditions with frost at night looks possible still across the North and West.
http://www.wetterzentrale.de/pics/Recm2401.gif
ECM 10 DAY MEAN (12z) The 240hr mean Chart from last night continues the theme of High pressure likely over the Atlantic in 10 days time with Low pressure to the east and NE meaning a cool Northerly flow likely over the UK with some showers by day and frost by night
http://www.wetterzentrale.de/pics/Reem2401.gif
NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS There is a more definitive agreement shown between the models this morning of High pressure becoming much more dominant across the UK next week, eventually positioning to the West and ensuring cooler air for many following a somewhat warmer phase midweek next week.
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 97.4 pts to UKMO's 96.8 pts while GFS lags behind at 95.8 pts. At 5 days ECM leads with 89.9 pts to UKMO at 87.6 pts and GFS at 85.1 pts. Then at 8 Days ECM has the leading spot from GFS with 64.9 pts to 59.4 pts. Finally at Day 10 ECM has the lead from GFS with a score of 42.4 pts to 38.3 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 models seem to be getting a good handle on the course of events over the next 4- 5 days across the UK although the longer term outlook still looks a bit mixed between the different models. In the short term there looks like a change to cooler but drier weather across the South and I know many have had a very pleasant couple of days others have seen some very heavy showers and these showers will if anything become more numerous and widespread in the coming days before colder and clearer air spreads down from the North over the weekend as the Low pressure that's been down to the SW finally exits east into Europe. The air will be very chilly for mid April and frosts at night under clearing skies will be a big feature early next week in the South whereas the North might turn more cloudy with a little rain as troughs brush East to the North. Thereafter it's all about how the High pressure responsible for the better conditions in the South moves North and allows a period of warmer SE winds ahead of a return to heavy showers later next week as Low pressure finds it's way North from Spain. The general theme then is for the possible return of colder NE winds as there is a lot of support for High pressure to become anchored out to the West of the UK with cool showery winds from Low pressure near the SE to affect Southern and Eastern areas at least but we are talking a long way out by then and confidence on any one evolution from late next week verifying comes with lower than usual confidence. What is more certain is that frosts at night remain a big risk at times over the coming few weeks with any Northerly influence escalating the risk further so gardeners beware. For the rest of us the next few weeks will probably end up having seen a lot of dry and fair weather for many just punctuated by April showers but if I had to be picky I would prefer to see rather more of a Southerly influence to the air-flows across the UK rather than the North especially given we are edging towards May.
Next Update Friday April 15th 2016 from 09:00
Martin G
Kilmersdon Radstock Bath Somerset