HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY TUESDAY NOVEMBER 18TH 2014.
NEXT UPDATE WEDNESDAY NOVEMBER 19TH 08:00
THE CURRENT GENERAL SITUATION A light Easterly airflow across the UK will slowly veer SE as a front approaches Western Britain tomorrow.
MODELS-2 WEEK HEADLINE Generally less unsettled for a time with a lot of cloudy but dry weather, perhaps becoming more unsettled and windy again later from the West.
THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows a weak and disrupted pattern over Europe as the Jet flow exits the USA, crosses the Atlantic and is diverted both North and South of mainland Europe with the UK lying in the Western periphery of this pattern. Little overall change is shown to this disrupted pattern as far as Europe is concerned.
GFS OPERATIONAL The GFS operational this morning shows a persistent block of High pressure over Eastern Europe with strong ridging towards Scandinavia persisting through much of Week 1 and preventing and major Low pressure from crossing Britain. However, some ingress of this is made into the UK delivering rain to some later in the first week before High pressure builds briefly from the SW with clearer and colder weather for a time ahead of strong winds and rain which evemtually is shown to power through as the High block collapses to the East. At the end of the run a strong WSW flow over the UK bring spells of rain in relatively mild weather for all.
THE GFS PARALLEL RUN The GFS Parallel run is broadly similar to the operational in Week 1 with only small but subtle differences in sequential and specific details before it diverges away from the operational in Week 2. High pressure on this run fails to decline to the East and a Scandinavian High pressure block is shown to develop later. As a result Atlantic Low pressure is diverted to the SW of the UK opening the door to a much colder wedge of air to move West across the UK from Europe.
THE GFS ENSEMBLES The GFS Ensembles lie much closer to the operational camp as the benign pattern of the first week with a little rain at times gives way to a more aggressive and deep Low pressure attack from off the Atlantic later next week. This then delivers spells of rain and very strong winds for all mixed with spells of squally showers and rather colder weather with snow on Northern hills.
UKMO UKMO today shows a trough crossing slowly East over the UK at the weekend with some rain for all before clearer and fresher air crosses the UK under a strong ridge from the SW. Frost and fog could develop for a time before SW winds increase in the NW late in the run heralding a new and stronger push of unsettled and windy weather into the UK next week.
THE FAX CHARTS The Fax Charts show a series of weakening occluded fronts slowly moving into the UK and decaying over the next 4-5 days. A little rain from these is likely in the West especially but a lot of dry and benign weather is shown in a slack SE flow with relatively trouble free temperature levels.
GEM GEM this morning shows the stand off continuing between High pressure to the East and later NE warding off the Atlantic low pressure with a steadily strengthening SE flow delivering rather cloudy weather but a lot of dry weather too apart from a few brushes from Atlantic fronts and resultant rainfall in the far West and SW. Towards the end of the run pressure falls and with Low pressure engaging both from the East and West some rain is likely for all in progressively lower temperatures.
NAVGEM NAVGEM this morning looks a lot like UKMO as it brings a ridge up from the SW over the weekend following a weakening front having previously moved East over the UK. After a little rain from this the weather would clear and become fresher with some frost and fog at night for England and Wales before SW winds and cloud invade from the NW later.
ECM ECM this morning takes the road towards much more unsettled weather in the latter stages of it's run as Low pressure tmbles SE across the UK later bringing wet and windy conditions at times and it would feel colder too with some snow possible on Northern hills. in the meantime we continue with a benign spell of weather under mild SE winds ad a weak cold front crossing East at the weekend with just a little rain for all at some point before a ridge from the SW introduces a change to fresher air and the subsequent aforementioned unsettled and windy weather later.
THE ECM ENSEMBLES The Ensemble run this morning's indicate a trend towards Low pressure gradually becoming more dominant again later next week as Low pressure out to the NW pushes South or SW winds across the UK with troughs delivering occasional rain from troughs in relatively mild conditions.
NOTABLE TREND CHANGES FROM PREVIOUS RUNS There still seems a lot of confusion between the models as we move through the second half of the output with the threat of deep Low pressure near the UK later just holding sway in trend this morning.
MY THOUGHTS There are marked differences still being shown in the second part of this morning's output as models struggle to decide on how to if at all they see the demise of the persistent block of High pressure over Eastern Europe. While this is there the passage of our normal West to East flow of depressions and fronts is thwarted and instead a benign and quiet spell of weather under a SE flow is maintained. However, they do all agree that a front will bring a shift in emphasis away from that High to the East, at least for a time as after the front a ridge of High pressure from the SW brings fresher and cleaner air across from the West perhaps with a night or two when frost and fog patches might develop. It's from that point early next week that differences in evolution emerge with the biased opinion leaning more towards Low pressure moving down over or close to the UK with strong winds and rain for all mixed up with more showery and chilly spells when some snow could fall on northern hills. This theme is supported by the GFS operational and Ensemble run together with the ECM operatational while GEM and to some extent the GFS Parallel run show Low pressure further to the Southwest engaging a colder pool of air from the East which could in theory bring some cold weather across the UK from the East but at this stage temperatures still don't look low enough to produce anything other than cold rain from all but the highest ground in the destabilising airmass though the theme will catch the eye for those lokking for colder weather. The ECM Ensembles which have been very volatile of late shows a sharpening of the trough stretching from a point SW of Iceland down across the UK and as a result of this it means a much more unsettled and potentially windy spell of weather being the most likely evolution likely after week 1 when taking all this morning's output as a whole.
Edited by user
18 November 2014 08:54:06
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Reason: Not specified
Martin G
Kilmersdon Radstock Bath Somerset