HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8PM TODAY THURSDAY AUGUST 7TH 2014.
NEXT EXCLUSIVE UPDATE ON MY WEBSITE FROM 22:00HRS TONIGHT
THE CURRENT GENERAL SITUATION. A light Westerly flow across the UK will continue through the day. Fronts will approach the SE from the SW overnight.
MODELS-2 WEEK HEADLINE Changeable and sometimes windy and cool with showers and some longer outbreaks of rain at times. Perhaps drier across the South later.
THE JET STREAM FORECAST The Jet Stream Forecast taken from the GFS Ensemble data shows the flow continues blowing West to east close to northern France strengthening markedly over the weekend and start of next week. It's trend then is for it to weaken and become much more fragmented but with a tendency to trough over the UK.
GFS The GFS operational this morning continues to show the weekend storm moving NE across the UK on Sunday and joining a deep Low pressure complex near Northern Scotland next week which slowly weakens under a slow pressure build from the SW. As High pressure slips East to the South on a week or so time Low pressure re-establishes from the North with Westerly winds to end the run. All this means very changeable conditions with rain or showers at times with a drier, brighter and warmer interlude towards 10 days time. The GFS Ensembles this morning endorse the above sequence of events well with Low pressure well in control of the weather bar a period in the middle of the run when a brief ridge brings a drier and warmer interlude.
UKMO UKMO this morning also shows the deep Low moving NE on Sunday being absorbed by a deep Low complex lying near Shetland and the Northern North Sea through the early part of next week with the heavy rain and strong winds of Sunday chased away by cool and very showery NW winds afterwards.
THE FAX CHARTS The Fax Charts show the small but vigorous Low cross Southern England later on Sunday with a cool and showery West or NW flow developing behind to start next week.
GEM The GEM operational throws a different complexion on events following the weekend storm which is interpreted to move NE across the South on Sunday and join the intense Low pressure zone near Northern Britain for some time early next week. Through this period wind and rain will be the main features and it will feel cool. Later in the run the weather settles down as High pressure ridges across from the South with the South and East becoming very warm and humid with the risk of thundery showers moving North by day 10.
NAVGEM NAVGEM this morning shows nothing more than a trough crossing Southern Britain on Sunday in an otherwise complex Low pressure structure which intensifies early next week over Northern Britain bringing strong winds and showery rain to all areas at times in cool weather. The end of the run supports a cool and showery WNW flow with the parent Low slipping across to Scandinavia.
ECM The ECM operational too supports less development of the Sunday feature and shows a more modest blow from the NW next week as pressure steadily recovers from the SW through next week. as a result some heavy rain and showers will be around for a while on Sunday and early next week before the trend towards drier and less cool conditions move across Southern and Western areas later.
NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models continue to struggle with the course and development of the remains of ex hurricane Bertha which throws the outlook beyond this feature wildly different from model to model.
MY THOUGHTS We are now three days away from the widely talked about ex-tropical storm and the models seem no clearer on either the development or path the system will take. This then makes predictions beyond Sunday speculative and unreliable as the development of the storm will have far reaching implications on the synoptic pattern next week and beyond. For example we have a strong split this morning between the camp that develop the system well and end up with a deep low complex over the UK (ala GFS, UKMO and GEM) for much of next week with cool, windy and showery weather while NAVGEM and ECM in particular make far less of the whole pattern and bring the UK back into fairly benign mid August weather soon afterwards with sunny spells and just well scattered showers. While personally I feel we will share some of the bad weather this ex tropical storm brings on Sunday and early next week I also feel that ECM and NAVGEM might have a better drift on the aftermath as the desire of pressure wanting to rebuild back from the SW later looks strong and joined by GEM later. However, having said that confidence in this and any other outcome has to be unusually low at this point and until the exact course and depth of this Atlantic storm on Sunday is nailed upon events shown thereafter can only be described as pure speculation.
Martin G
Kilmersdon Radstock Bath Somerset