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 JULY 21ST 2015
THE CURRENT GENERAL SITUATION. A WSW flow across the UK will generally persist for the next 24-48hrs delivering scattered showers and bright conditions.
http://www.wetterzentrale.de/pics/Rtavn001.gif
MODELS-2 WEEK HEADLINE Still rather changeable with some dry and bright conditions mixed with occasional rain or showers. Becoming drier and warmer everywhere later in the period.
THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast keeps the flow blowing West to East across the South of the UK this week albeit quite lightly. Towards the start of next week it strengthens and if anything troughs further South than the UK for a time before it finally breaks up or shifts North in much lighter conditions by the end of the period.
http://www.netweather.tv/index.cgi?action=jetstream
GFS OPERATIONAL The GFS Operational Run today is not dissimilar to yesterdays morning's output in that this weeks slack and benign weather pattern becomes replaced by a deep Low early next week with rain and showers in abundance then as well as some quite cool weather. It then becomes replaced by High pressure from the West, on this run across northern Britain while the South sees the remains of a cut off Low pressure area just to the South possibly delivering some thundery showers in the extreme South.
http://www.wetterzentrale.de/pics/Rtavn1441.gif
http://www.wetterzentrale.de/pics/Rtavn3841.gif
THE GFS CONTROL The GFS Control Run is fairly similar in many respects, certainly in the early to mid run while the end of the period is less clear cut in detail as the High pressure build shown by the operational run at the end of the period being a little more ragged with an eventual pull of it back West out into the Atlantic with some showery rain in the NE on a cool NW flow again.
THE GFS CLUSTERS(14 Days) The GFS Clusters at 14 days still indicate a lot of support for High pressure to be lying close by, most likely just to the West with a lot of fine weather suggested for most areas. As always there is some conflicting charts to this pattern in the shape of Atlantic Low pressure towards the North but only amounting to around 20% of members today.
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 benign conditions over the weekend as Fridays threat of Low pressure looks restricted to showers in the South before a fine weekend develops with some pleasant sunshine for many. By the start of next week though Low pressure steams in from the West with rain and showers for all in cooler and breezier conditions overall.
http://www.wetterzentrale.de/pics/Rukm1441.gif
THE FAX CHARTS The Fax Charts this morning show a somewhat showery theme between now and Friday with the impending Low pressure to the SW on that day pulled further South on this morning's run leaving much of the UK unaffected. The weekend then shows a weak High pressure area near the South with fine and dry conditions likely as a result.
http://www.weathercharts.org/ukmomslp.htm#t120.
GEM GEM today shows showery Westerly flow with Friday's Low a little more influential to the South than other models suggest with some rain and cool conditions Friday. A quiet and largely dry weekend is then shown under a ridge with next weeks Low further North than other output, this time being most influential to the North where the most wind and rain from this falls while the South sees little. Then all areas become fine, warm and settled later next week as High pressure builds strongly across the UK.
http://www.wetterzentrale.de/pics/Rgem2401.gif
NAVGEM NAVGEM today shows slack Westerly breeze, sunshine and showers for the remainder of this week with Friday's Low amounting to nothing before a ridge gives a decent weekend for many. next week's Low on this run though looks a fairly potent feature given the time of year crossing the UK and delivering rain, showers and cool conditions for all for a time.
http://www.wetterzentrale.de/pics/Rnvg1681.gif.
ECM ECM is encouraging longer term again today with High pressure building across the UK late in it's run following a spell of cool and unsettled conditions in West then NW winds next week, all this following the rest of this week's rather benign and slightly changeable conditions..
http://www.wetterzentrale.de/pics/Recm2401.gif
ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last night shows Low pressure over Scandinavia with winds from between West and North across the UK with a typical pattern of sunshine and showers in average temperatures at best most likely by Day 10.
http://www.wetterzentrale.de/pics/Reem2401.gif
NOTABLE TREND CHANGES FROM PREVIOUS RUNS There is a growing trend with cross model support from those models that look aheadthat far that High pressure is likely to build across the UK as we enter August.
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 95.4 pts followed by UKMO at 94.9 pts and GFS at 94.0 pts. At 5 days ECM is stll king at 84.2 pts followed by UKMO at 80.7 and GFS at 80.5 pts. Then at 8 Days ECM still leads at 53.1 pts over GFS's 46.9 pts. Finally at Day 10 ECM leads GFS at 33.9 pts to 28.3 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 main theme of this morning's runs are the trend towards a different pattern synoptically showing up across the UK on a UK wide basis from later next week. In the meantime there is still a lot of days to come of indifferent conditions, often benign and quiet with sunny spells and the odd shower but occasionally rather wetter for some. The models have backed away from this Friday's earlier predicted Low pressure with only a glancing blow likely if any across the far South before a decent weekend turns up within rising pressure. It's next week when the interest begins with a deepening Low supported by most output crossing the UK and away to the NE through the early days of next week with a cool NW flow in it's wake giving rise to cool conditions along with sunshine and showers. Thereafter a pattern change is signified as High pressure builds into the UK from the Atlantic, settling over the top of us and bringing the best chance for some considerable time of a nationwide spell of fine and warm weather. My only worry is that the high centre may stay a little too far to the West or SW always maintaining something of a North or NW feed across the UK hence lower temperatures but this is speculation at the moment. Of course at this range there is a lot of water to cross under the bridge anyway before definintive certainties can be applied but the signs are encouraging with good support from ensembles, clusters etc. So while we have a week or so to go with weather as mixed as ever we should all look forward to something much more universally better across the UK from later next week.
Next update from 09:00 Wednesday July 22nd 2015
Martin G
Kilmersdon Radstock Bath Somerset