HERE IS MY LATEST EXTENDED SUNDAY ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SUNDAY NOVEMBER 9TH 2014.
NEXT UPDATE MONDAY NOVEMBER 10TH 08:00
THE CURRENT GENERAL SITUATION. A slack and cyclonic Westerly flow covers the UK today. Winds back Southerly and strengthen tomorrow as an active front edges slowly East across the UK.
MODELS-2 WEEK HEADLINE Unsettled with rain at times across the British Isles with strong winds too and temperatures near to normal. perhaps becoming a little colder and drier from the North later.
THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows the flow continuing to be forced to a position to the South of Britain over the next week keeping the UK in a cyclonic flow. Later in the period the flow splits into two with a Northern and Southern arm, the latter weakening and ridging North over and around the British Isles later in Week 2 and linking with the Northern arm over Iceland and Northern Scandinavia.
GFS OPERATIONAL Today's GFS operational run shows the UK continue to see areas of Low pressure crossing the Atlantic and into the UK from the West where they become slow moving and fill slowly bbringing spells of rain, heavy at times along with strong winds in average temperatures. Through the period the desire to build pressure from the North remains and succeeds through week 2 with winds switching Easterly and bringing further rain at times to the South and drier conditions near High pressure close to the North later. Temperatures would probably fall to a little below average in this new setup.
THE GFS PARALLEL RUN The GFS Parallel run carries the same sequence of events though differs in Week 2 by collapsing High pressure to the North SE over Europe and cutting off any route to colder and prolonged drier conditions for the UK as well as bringing the UK back under attack of Atlantic Low pressure from the West and SW later with it's subsequent wind and rainfall.
THE GFS ENSEMBLES. The GFS Ensembles are broadly similar in message with a wet first week under slow moving UK Low pressure being forced South in Week 2 in rising pressure from the North and NE with an ESE flow developing with drier and chillier weather as a result, chiefly in the North and East. Low pressure over the Atlantic will continue to run up against this block centred over Europe by then and keep the risk of rain and strong SE winds going for the South and West.
UKMO. UKMO today shows Low pressure deep and persistent out to the West and NW of the UK through this week with spells of rain and heavy, thundery showers going into next weekend in relatively mild conditions.
THE FAX CHARTS The Fax Charts show a series of occlusions and showery troughs edging slowly East across the UK through this week each bringing their own variety of wind, rain and thundery showers across the UK all connected around deep Low pressure anchored to the West of Ireland.
GEM GEM shows Low pressure in total control of the UK weather over the next week spinning in from the West towards SW Britain with heavy rain and showers at times as a result in average temperatures if not somewhat mild in places. Later on pressure rises over Northern Europe and a SE wind setsup with Low pressure then to the SW with further rain here at times while Northern and Eastern parts become drier and less mild.
NAVGEM NAVGEM keeps Low pressure in complete domination over the UK through next week with the main centre out to the NW next weekend with showers or longer spells of rain in relatively mild and strong South or SW winds for all as a result.
ECM ECM this morning shows unsettled and relatively mild weather over the next week with rain and showers, heaviest and most prolific across Southern and Western areas. Over next weekend and the following week pressure is shown to rise to the North and NE with winds switxhing towards an Easterly point as well as being quite strong. Although feeling colder temperatures will only fall modestly and with Low pressure still entrained across the Atlantic to the South and SW further rain at times looks like it would edge up into Southern Britain at times too in the mostly cloudy flow.
THE ECM ENSEMBLES The ensembles point to a continuation of broadly unsettled weather with rain at times across the UK in average temperatures and a SE flow as Low pressure continues to stretch from Southern Greenland to the SW of the UK. Some of the rain will be heavy and winds look like continuing quite strong at times. Pressure remains High to the NE of the UK at that time.
NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend today still shows a chance of High pressure developing to the North and NE bringing drier conditions to the North and East in Week 2 with slightly colder weather.
MY THOUGHTS The synoptic pattern over the UK and surrounding waters remain very complex over the next few weeks. The UK remains in the firing line for deep Low pressure moving across the Atlantic and stalling near our shores through this week with rain and showers for all areas as a result and it will stay generally windy and relatively mild. I guess the interest for many occurs from around next weekend when pressure builds strongly to the North and NE of Britain and this theme is shared by all output. This then forces Low pressure out of Britain and to the South and SW with a SE or East flow likely to develop across the UK in some shape or form through week 2. This would normally introduce much colder and potentially wintry weather to the UK but this looks unlikely as Europe remains much milder than average and the orientation of such High pressure does not permit any interaction with cold Arctic air as things are shown currently plus of course we are still very early into the Winter Season. So due to all these factors the most likely pattern to evolve will be of a chillier East or SE wind bringing drier conditions to North and East Britain but with a lot of cloud and the brightest conditions towards areas such as West Scotland on the leeward side of high ground. It also looks like Low pressure will never be far away from the South and SW and the desire to pull this back across the UK late in the period is hinted at by some output and it maybe that Southern Britain remain unsettled with rain at times anyway. My own thoughts at the moment are that it looks unlikely that this pattern will evolve in such a way that brings cold weather to the UK on this occasion and could end up being just a cloudy and benign coolish period before the Atlantic wins back. Nevertheless, like last night's ECM operational showed there is always potential when the synoptics setup in the way and it only needs a change of orientation of the High and Low pressure features to change my opinion to something rather colder but I conclude that this is not shown this morning so I don't expect the Met Office to indicate any note of particular change in the mid range forecasts unless cross model support for something more wintry is shown consistently for several days at least and we're not even on the treadmill to that goal yet.
Originally Posted by: David M Porter