HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON THURSDAY MAY 7TH 2015.
THE CURRENT GENERAL SITUATION A weak ridge of High pressure moves NE over the Uk today replacing the showery westerly flow followed by a trough of Low pressure edging towards the SW tonight.
http://www.wetterzentrale.de/pics/Rtavn001.gif
MODELS-2 WEEK HEADLINE Changeable with some rain at times but a dry and warm period across the South and East early next week.
THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream will ridge North across the UK to be blowing in a NE direction across the British Isles over the next 4-7 days. It then is shown to change trajectory at the same time as moving back South under a UK trough in Week 2 before becoming less defined in both strength and location at the end of the period.
http://www.theweatheroutlook.com/twodata/datukgfshires.aspx?display=jetstream&model=gfs
GFS OPERATIONAL The GFS Operational this morning shows a period of warmer and more humid conditions developing over the latter half of the weekend and start to next week as pressure builds to the SE sending rain bearing troughs towards the North and West only in a Southerly or SW flow. However, this is shown to be shortlived as Atlantic Low pressure sweeps the warm air away East over Europe with a very changeable and cooler period following with strong Westerly winds and rain at times thereafter. In the latter stages of the run the unsettled theme continues with Low pressure close to the East of the UK and cool winds blowing over all areas.
http://www.wetterzentrale.de/pics/Rtavn1441.gif
http://www.wetterzentrale.de/pics/Rtavn3841.gif
THE GFS CONTROL The GFS Control run once more closely follows the theme of the operational with the warm and dry theme for a time next week across the South and East slowly giving way to more unsettled and windy weather with rain at times as Low pressure crosses east to the North of the UK before the desire to bring cool uppers down across the UK late in the run is less marked than with the operational but still shown to affect the UK in a modified way.
THE GFS CLUSTERS The GFS Clusters show an 80/20 split in likely conditions two weeks from now in preference of a likely ridge lying across the UK from an Atlantic anticyclone with any rain restricted to the far NW but temperatures held close to average by a West to NW breeze. Only 10% of output shows anything resembling unsettled weather spreaading further South across the UK rather than just the NW.
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 UKMO this morning shows things warming up at the start of next week as High pressure to the SE sucks up some warm and humid air across Southern and Eastern Britain. However, it looks unlikely to last long as the warm air is pushed away East by growing influence of Low pressure to the North and NW with stronger cooler winds and some rain for many by midweek.
http://www.wetterzentrale.de/pics/Rukm1441.gif
THE FAX CHARTS The Fax Charts show a similar evolution with a complex array of troughs and Low pressure at the weekend with attendant rain and showers dissolving as a warm surge of air from the South embraces Southern and Eastern Britain early next week when 25C could be reached in the SE for a time.
http://www.weathercharts.org/ukmomslp.htm#t120.
GEM GEM this morning also shows the surge of warm air across the South and East early next week rather slower to give way to more unsettled conditions from off the Atlantic. However, it does eventually remove it away East with all areas eventually coming under the influence of a strong Westerly flow with rain at times, heaviest over the North.
http://www.wetterzentrale.de/pics/Rgem2401.gif
NAVGEM NAVGEM too shows warmer air across the South and East early next week shunted away East by a cold front midweek and a deep Low pressure to the NW of the UK by next weekend with strong winds, rain then showers for all together with cooler conditions.
http://www.wetterzentrale.de/pics/Rnvg1681.gif.
ECM ECM shows warm and muggy air sucked up across the UK early next week, lasting several days before a thundery trough moves NE over the UK around the middle of the week with fresher cooler air moving NE over all areas. Conditions then continue to be shown to deteriorate as a deep Low moves East to the North of Britain with strong and cool West winds and rain or showers at times for all gradually clearing away from the SW late in the run.
http://www.wetterzentrale.de/pics/Recm2401.gif
ECM 10 DAY MEAN(12z) The ECM 10 Day Mean Chart from last night shows quite a cool and changeable pattern looking likely in 10 days time with a West to East Jet flow likely to be blowing across the South of Britain, Low pressure close to the North and a blustery and chilly WNW flow across the UK with some rain or showers a risk for all.
http://www.wetterzentrale.de/pics/Reem2401.gif
NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models continue to suggest that changeable conditions look likely to continue for the next two weeks at least.
31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.2 pts followed by UKM at 96.6 pts and GFS at 95.9. At 5 days ECM leads UKMO with 87.8 over UKMO's 86.6 pts with GFS at 84.1. At 8 days ECM remains the leader with 56.8 pts over GFS's 55.0 pts. Then at Day 10 ECM gains superiority at 38.2 pts over GFS at 37.6.
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.prig
MY THOUGHTS Things still look very changeable across the UK over the two week period of the output this morning with something for everyone at some point or another. The current theme of showers and rain at times have another couple of days or so to run yet as a new Low and troughs drift NE across the UK with rain tomorrow and showers on Saturday and blustery winds in places. Then the most pleasurable period of weather across the South and East of Britain looks like taking place between Sunday and Wednesday as building High pressure to the SE sucks up some warm and humid conditions from the South when 25C is possible in places for a time in the SE. Unfortunately it increasingly looks only a shortlived event and never reaches the NW as the Atlantic looks like biting back from midweek. The breakdown will probably take the shape of a band of thundery rain crossing England and Wales midweek and then followed by windier and fresher conditions as a deep Low sets up near North or NW Britain with cool and strong breezes for all bringing spells of rain and showers West to East across all areas late next week. The longer term models then look like carrying this theme on through Week 2 too with rain and showers and quite cool charts shown from the GFS extended runs and although some output show High pressure not too far away in the extended outlook the positioning of the Jet stream forecasted for that time along with poorly aligned High pressure probably to the West or SW indicates the threat of chilly winds from a NW point look most likely to be keeping the average temperatures going right out to the end of the run with the further threat of rain at times especially towards the North.
Next update from 08:00 Friday May 8th 2015
Martin G
Kilmersdon Radstock Bath Somerset