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 SUNDAY SEP 13TH 2015.
THE CURRENT GENERAL SITUATION Low pressure will become dominant and complex near to SW England tomorrow with cyclonic and in places strong winds across the British Isles.
http://www.wetterzentrale.de/pics/Rtavn001.gif
MODELS-2 WEEK HEADLINE Becoming unsettled and often windy with rain or showers at times though perhaps drier for a time especially in the South early next week.
THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow well to the South of the UK blowing strongly West to East or SW to NE over France and Northern Spain keeping the UK on it's northern flank and under a trough. after a week or so the flow migrates North to Scotland at the same time as weakening with hints of it moving further NW still at the end of the period.
http://www.netweather.tv/index.cgi?action=jetstream
GFS OPERATIONAL The GFS Operational Run today shows a very unsettled week to come with several Low pressure areas making the UK their home over the next week, each offering their own version of wet and windy weather with some heavy and thundery rain at times, most concentrated across Southern areas with brighter more showery weather at times too. By next weekend and beyond the emphasis of wind and rain shifts towards the North as High pressure desperately tries to move into the UK from the SW. It is shown to be a painfully slow progress but by the end of the run many places look to have become dry, bright and relatively benign for a time.
http://www.wetterzentrale.de/pics/Rtavn1441.gif
http://www.wetterzentrale.de/pics/Rtavn3841.gif
THE GFS CONTROL The theme of the GFS Control Run this morning is copycat of the operational for the next 5-7 days with unsettled and windy weather for all with heavy rain at times. It too then shows a brief improvement over the South in just over a weeks time before unsettled weather returns from the NW as Low pressure slips SE over Britain last to leave the SE. Pressure then rises from the North and several days of benign conditions look likely before Low pressure over the Atlantic edges troughs towards SW Britain again before the end of the period.
THE GFS CLUSTERS(14 Days) The GFS Clusters this morning are very diverse as members offer conflicting messages ranging from wet and windy to calm and settled weather. The emphasis though is around 50/50 perhaps with a slight bias towards influence from Low pressure more than High pressure being dominant.
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 Low pressure well in control of the UK weather throughout this week with heavy rain and showers mixed with occasional gales likely for many at times. It does show better conditions moving across the UK next weekend though as a ridge of High pressure builds across the UK from the South.
http://www.wetterzentrale.de/pics/Rukm1441.gif
THE FAX CHARTS The Fax Charts this morning show complex areas of Low pressure moving North into the South of the UK where they become slow moving before being reinforced by further centres following a similar track meaning very unsettled and often very windy weather for the UK especially over the South
http://www.weathercharts.org/ukmomslp.htm#t120
GEM GEM today looks very changeable through it's 10 days with very wet and windy spells across the UK over the next 5 days under complex UK based Low pressure before cool and showery NW winds ahead of a ridge lead to a better period to start the second week. It isn't long though before Low pressure, this time to the NW is shown to move SE across the UK to return unsettled and sometimes wet weather to all by midweek of the second week.
http://www.wetterzentrale.de/pics/Rgem2401.gif
NAVGEM NAVGEM shows wet and windy conditions at times too throughout this week as various Low pressure areas affect the UK as they pass over. Then as with much of the other output pressure rises somewhat next weekend with a better period especially over the South under a simplified Westerly flow with some rain at times still over the North.
http://www.wetterzentrale.de/pics/Rnvg1681.gif
ECM ECM this morning also looks very unsettled through the working week with rain, gales and sunshine all possible as deep low pressure areas cross the South at times. then by the weekend pressure is shown to rise markedly with dry and fine weather developing for many next weekend. How long it lasts is unclear as the model shows just a tenuous hint of a continuation of this drier spell as High pressure to the NE and SW link under conflictingly falling pressure over the UK.
http://www.wetterzentrale.de/pics/Recm2401.gif
ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last night shows Low pressure up to the NW and a generally Westerly flow across the UK with no doubt rain at times, heaviest towards the North and West with some drier spells in the South and East closer to High pressure to the SW and France.
http://www.wetterzentrale.de/pics/Reem2401.gif
NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models are universally supportive of 5-6 days of often wet and windy weather followed by something of an improvement over next weekend with no clear pattern of any improvement lasting or not from then on.
31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM show at 24 hours ECM leads UKMO at 99.4 pts to UKMO's 99.3 pts with GFS coming in third at 99.1 pts. At 3 days ECM ties at 96.1 pts with UKMO while GFS lags behind at 95.2 pts. At 5 days UKMO is king at 85.7 pts followed by ECM at 85.2 and GFS at 83.2 pts. Then at 8 Days ECM still leads at 59.6 pts over GFS's 50.2 pts. Finally at Day 10 ECM leads GFS at 38.9 pts to 32.9 pts from GFS.
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.prig
MY THOUGHTS Though details from run to run are sometimes quite stark in the positioning of individual Low pressure areas over the coming week the message is the same from all output in that we are all going to see several spells of rain this week mixed with brighter showery conditions. What is less clear is whether that will be accompanied by potentially gale or severe gales. The positioning of Low pressure this week will be crucial in facilitating high winds with a more Northerly aspect to their passage giving the South a real battering while if they stay over the English channel or France then high winds are more unlikely. However, whatever happens through the week there remains a strong message that things may improve for a time next weekend as all models show a ridge of High pressure at least making an unusual if temporary weekend visit to our shores with dry and benign conditions likely. Then as we look into the longer term there is also a suggestion that Low pressure will reignite up to the NW and bring back more unsettled and windy weather with rain at times in Week 2 probably most focused towards the North and West. To be honest though with so much complexity in the atmosphere from ex tropical storms over the western Atlantic details of a period of time more than a week from now become quite futile and need to be explored later this week when the worst of this week's pool of Low pressure starts to move away and a clearer indication of the extent and longevity of next weekend's improvements are better understood. So in a sentence a wet and potentially very windy period of weather at times is likely over the next 5-6 days with less volatile and more benign Autumn weather arriving next weekend and possibly lasting for a time into the second week.
BEST CHART OF THE DAY 00z RUN
http://www.wetterzentrale.de/pics/Recm1681.gif
In selecting the best Chart of the Day today I have gone for the Day 7 Chart from ECM with a High pressure ridge having built strongly across England and Wales over the preceding 24 hours. Though in this run the ridge weakens in the following days it offers a period of relatively dry and benign typically quiet early Autumn conditions for several days across the UK.
WORSE CHART OF THE DAY 00z RUN
http://www.wetterzentrale.de/pics/Recm961.gif
For the worst chart I have gone for the ECM 4 day chart for midnight on Thursday although I could of picked any model's chart at that time point to highlight what is likely to be the pinnacle of the worst weather of the week. While the Low on this chart is harmlessly crossing NE over Southern England with SW gales kept across France any deviation further to the NW of this Low's movements could result in SW gales of some magnitude across Southern Britain and more especially the South Coast which could lead to some disruption. This Low is the one to watch this week as it has the potential to become newsworthy while on the other hand it may not depending in a shift of movement to that shown above by just a 100mls or so to the NW.
Next update from 09:00 Monday Sep 14th 2015
Edited by user
13 September 2015 08:26:43
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Reason: Not specified
Martin G
Kilmersdon Radstock Bath Somerset