HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY FRIDAY NOVEMBER 21ST 2014.
NEXT UPDATE SATURDAY NOVEMBER 22ND 08:00
THE CURRENT GENERAL SITUATION A complex series of troughs will move slowly NE across the UK today and become slow moving near to SE Britain from tomorrow morning with wave disturbances running North along it at times over the weekend. Pressure rises strongly across the North from tomorrow.
MODELS-2 WEEK HEADLINE Slowly becoming windier and more changeable next week and beyond with rain or showers and strong winds at times moving down from the NW. Temperatures near or a little below average.
THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows the disrupted flow to the West of the UK continuing over the next week with something of a split flow over Europe-one arm high over the Arctic and another one well South over the Med or North Africa. The pattern simplifies in Week 2 as the pattern flattens and a strong flow crosses the Atlantic and Southern Britain later in the period.
GFS OPERATIONAL The GFS operational this morning shows asteady trend towards a more unsettled spell as Low pressure develops and moves down from the NW later next week. There will be spells of rain and showers as a result in temperatures close to or slightly below the seasonal average in increasingly blustery winds. Through Week 2 the winds remain strong and from the West with further spells of rain with temperatures recovering to average or somewhat above in the South as the pattern flattens to a more traditional West to East flow of Low ressure to the North of the UK.
THE GFS PARALLEL RUN The GFS Parallel run is basically similar in trend and sequence of events with the unsettled and breezy weather revolving around deepening Low pressure over the UK later next week gradually simplifying as pressure rises from the South with Low pressure then to the North carrying wind and rain to more especially Northern areas later while the South sees longer drier phases when temperatures will reach and exceed normal values at times.
THE GFS ENSEMBLES The GFS Ensembles agree with the first half of the partner runs in as much as deep Low pressure develops close to Southern Britain later next week with much wind and rain for all as a result. It then diverges away from the operational and parallel runs in as much as it maintains deep Low pressure sweeping East over the UK rather than to the North with potentially quite stormy conditions at times in periods of rain and showers and temperatures close to average overall.
UKMO UKMO today shows very benign conditions under a slack pressure area from Days 4 to 6 with variable conditions as a result with a mix of sunshine, mist, fog, frost and a little rain all possible with a little sunshine too for the lucky few. Conditions do look like deteriorating from the NW soon after close of the run.
THE FAX CHARTS The Fax Charts continue to show a complex pressure pattern under basically High pressure over the weekend and start to the new week. Complex frontal activity will prevail near the SE of the UK for the next 72 hours and again by 120hours as well as new versions approaching from the West at the end of the Fax period.
GEM GEM this morning shows the UK remaining the battleground between a block of High pressure over Europe and repetitive Low pressure moving in off the Atlantic and disrupting SE while filling over the UK. This means that after a quiet period early next week more wind and rain is likely thereafter in temperatures close to average but feeling chilly in blustery winds at times.
NAVGEM NAVGEM also shows the theme of Low pressure developing and sliding down towards the UK from the NW later next week with rain and wind increasing in intensity and extent with time in blustery winds too but average temperatures overall.
ECM ECM this morning remains in the habit of being somewhat different to the majority, this morning making rather less of the disrupted Low pressure pattern of later next week before pulling Low pressure further towards a position North of the UK and subsequently taking a lot of it's rain with it while the majority of the UK remain bathed in a relatively mild and Westerly pattern.
THE ECM ENSEMBLES The Ensemble run continues to show a deep trough lying from Southern Greenland through the West of the UK to the Meditteranean with cyclonic South or SW winds across the UK with spells of rain and showers for all likely in average tmperatures overall.
NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend still is relatively one of Atlantic Low pressure gradually taking control of the weather with some disagreement on the positioning and resulting surface conditions in what remains a largely wintry free run.
MY THOUGHTS The output remains very mixed in detail between the models but the general message from them all is similar in that all areas are going to see rain at times across the period. For a time with Low pressure predicted to lie close to or indeed over the UK later next week some very wet weather is likely in places with winds occasionally strong but variable in direction. At this time temperatures may be held back close to or a little below average at times. Thereafter the general trend with exceptions is for Low pressure and the Jet Stream to move North and flatten. There is some evidence that Low pressure will go far enough North in Week 2 to bring drier air across Southern areas from High pressure developing to the South which of course means mild Westerly winds as a result. However there remains enough support too for very unsettled and windy and at times wet weather to persist for all under deep Low pressure lying close to the UK. The High pressure block to the East remains in situ but has shifted away from supplying too much influence to the UK later as the barrage of Atlantic Low pressure overrides it and displaces any chance of cold from a Continental source reaching the UK on this occasion. A more worrying trend is the rise of pressure to the South which is shown on several outputs this morning which coupled with High pressure over Eastern Europe could form an unwelcome Euro High block to the SE of the UK with a mobile Atlantic setup developing delivering most wind and rain to the North and West later. Once this pattern has formed it can prove stubborn to shift and delay a shift towards a more seasonal pattern while maintaining the string of warmer than average months that have occurred this year. However, there is a lot of water to pass under the bridge before we reach that stage and we still have the ECM Ensemble data this morning showing more support for a more entrenched and deep UK trough keeping things volatile and unsettled for all.
Originally Posted by: GIBBY