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 TUESDAY AUG 11TH 2015
THE CURRENT GENERAL SITUATION A ridge of High pressure will lie across the UK for the next 24-36 hours. Thundery Low pressure will move up towards the South of England later tomorrow.
http://www.wetterzentrale.de/pics/Rtavn001.gif
MODELS-2 WEEK HEADLINE Remaining rather changeable with some rain at times. Some dry and at times warm, humid conditions are likely for all areas as well.
THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow weakening across the UK in the coming days and resetting to the NW of the UK brieflywith another arm crossing the Atlantic towards Spain. The pattern remains complex through the period with the flow always lying close to or over the UK in a NE direction and occasionally West to East flow across the UK in response to Low pressure often to the North or NW.
http://www.netweather.tv/index.cgi?action=jetstream
GFS OPERATIONAL The GFS Operational Run today shows a thundery Low moving North within 48 hrs across the South of the UK and then continuing North to become absorbed by general Low complex to the North or NW with thundery rain and showers for most areas from Thursday to Sunday. Thereafter pressure is shown to build for a time across Southern Britain with warm sunny spells before the end of the period sees Low pressure take command again, centred over the UK with cool, breezy and unsettled weather for all.
http://www.wetterzentrale.de/pics/Rtavn1441.gif
http://www.wetterzentrale.de/pics/Rtavn3841.gif
THE GFS CONTROL The GFS Control Run shows a changeable week to 10 days to become as thundery Low pressure moves North and as the operational becomes absorbed in genearal Low pressure to the North of the UK. The rise in pressure from the South is shown but more gradual on this run taking until midweek next week to take hold over he South. Then several days of set fair weather under a ridge slowly pulls back South towards the end of the run returning the North to westerly winds and rain at times to end the run.
THE GFS CLUSTERS(14 Days) The GFS Clusters this morning still indicate a lot of High pressure out to the SW of the UK in two weeks time with a ridge stretching influence across the UK especially the South. Just a 15% of members show something much more unsettled with Low pressure near Scotland and rain at times for all under Westerly breezes.
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 today shows a thundery Low moving North across the UK on Thursday and Friday opening the door to a fresher Westerly flow with embedded troughs delivering some rain or showers to all at times but with some lengthy dry and bright spells too especially over the South.
http://www.wetterzentrale.de/pics/Rukm1441.gif
THE FAX CHARTS The Fax Charts this morning show the same thundery Low moving North with it's attendant warm and humid unstable airmass ahead of a cold front moving east across the UK by the weekend returning cooler and fresher air with more occasional rain and showers across the UK through the weekend.
http://www.weathercharts.org/ukmomslp.htm#t120.
GEM GEM today is not particularly inspiring if it's a different pattern than of late your after. It too shows thundery Low pressure migrating North later this week which then opens the door to fresher Westerly winds and occasional rain or showers with just brief drier and more settled interludes in the South.
http://www.wetterzentrale.de/pics/Rgem2401.gif
NAVGEM NAVGEM too holds Low pressure in control over the UK throughout the latter stages of it's run this morning as the thundery Low moves to the North and then settles a trough near or over the UK in cool Westerly winds with rain or showers at times for many.
http://www.wetterzentrale.de/pics/Rnvg1681.gif.
ECM ECM this morning looks a little different in it's latter stages. The first week of the run is much as the rest of the output with thundery Low pressure moving North with Westerly breezes moving across the UK in it's wake with showers especially across the North and West. Improvements are then shown to take shape later next week as High pressure builds across the South from the East with warm and humid weather returning to the South though it does look like the risk of a further thundery breakdown may not be far away after Day 10.
http://www.wetterzentrale.de/pics/Recm2401.gif
ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last evening shows the trough to the NW weaker and less in control over the UK as a large High pressure bias to the South of the UK could ensure plenty of dry, fine and warm conditions with any rain or showers from the trough to the NW focused on the NW.
http://www.wetterzentrale.de/pics/Reem2401.gif
NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models trend changeable today with various options between the models still desiring a return to Atlantic airflow domination.
31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 95.8 pts followed by UKMO at 95.4 pts and GFS at 94.6 pts. At 5 days ECM is stll king at 86.0 pts followed by UKMO at 84.6 and GFS at 84.0 pts. Then at 8 Days ECM still leads at 58.6 pts over GFS's 55.3 pts. Finally at Day 10 ECM leads GFS at 39.7 pts to 34.4 pts from GFS.
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 The models remain very mixed especially in the longer term though the first week of the output does offer some consistency. In the immediate future all interest focuses on thundery Low pressure advancing North from Biscay and Spain across Southern and Central Britain on thursday and Friday. My own feeling about this is that I'm not convinced there will be a lot of electrical activity from this but there will certainly be some, areas to be determined yet. more likely areas of thundery rain will move North ahead of an opening door to a return of fresher and cooler Westerly winds for the weekend and beyond. When the thundery weather exits the North it looks like all areas will have a mix of sunny spells and occasional rain or showers especially towards the North and West. As in previous days it's from that point on things become much more difficult to pin down as some output wants to build High pressure across the UK at some point while others want to keep a stronger Atlantic influence with a continuation of the North/South split we have encountered of late. Which is right is still impossible to call with I'd say about an equal chance of verifying. I think that until we have moved this continental feature out of the playing field by the weekend conditions for later August may look clearer but unfortunately though there is some waarm or even very warm charts to drool over again this morning they don't come with much cross model support as yet so expect up's and down in long term analysis to continue for some days yet in subsequent runs. What none of the models show is anything particularly out of the ordinary so standard late Summer conditions look more likely than not for most for most if not all of the time.
Next update from 09:00 Wednesday Aug 12th 2015
Martin G
Kilmersdon Radstock Bath Somerset