HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SUNDAY NOVEMBER 16TH 2014.
NEXT UPDATE MONDAY NOVEMBER 17TH 08:00
THE CURRENT GENERAL SITUATION. Slack low pressure continues to lie close to Southern England with a trough moving West over England and Wales tonight.
MODELS-2 WEEK HEADLINE Becoming generally less unsettled with a lot of dry and bright weather with just occasional rain. Temperatures near or a little above average. Perhaps becoming somewhat colder later
THE JET STREAM ENSEMBLE FORECAST The GFS Jet Stream Ensemble forecast shows a very complex and uncertain pattern over our part of the Northern hemisphere over the coming two weeks. In general there will be a tendency for there to be a split flow, one flowing East over the Arctic while a complex Southern arm undulates and disrupts towards the west and SW of the UK. Later in week 2 the flow simplifies to a single flow, blowing strongly across Greenland and Iceland before travelling SE over Scandinavia.
GFS OPERATIONAL The GFS operational this morning indicates High pressure becoming the dominant force affecting the UK weather over the two weeks. This starts the period over Eastern Europe extending a ridge across Scandinavia and the UK later this week before being reinforced by a new centre close to NW Brirain slipping South later. This wards off any major Atlantic attack though some fronts will make inroads from the West at first and the North later with a little rain. Temperatures will remain close to or a little above average to begin with but will probably fall off with time as the incidence of clearer skies permits more in the way of frost and fog at night to develop, slow to clear by day.
THE GFS PARALLEL RUN The GFS Parallel run shows a similar evolution in the short term with a gradual transition towards High pressure based dry if rather cloudy weather for most once this weeks weakening troughs move out of the way later. In Week 2 High pressure forms a new centre close to the UK drifting NE and allowing a colder feed of Easterly winds later which coupled with lower pressure developing brings rain to the South eventually extending to all areas later as the High to the East recedes away.
THE GFS ENSEMBLES. The GFS Ensembles show slightly less domination from the High over Europe this week with a slack if rather mild SE flow for many and occasional troughs moving North over the west of the UK maintaining ccasional rainfall here while the East stays largely dry. Then a more concerted push of rain and attendant Low pressure clears East and allows a new High to form over Northern Britain setting up a large UK based High pressure system for much of the rest of the run with colder and perhaps frosty and foggy conditions developing thereafter.
UKMO. UKMO today shows a slack SE flow later this week strengthening later as Low pressure and fronts approach the UK from the West by next weekend. East is best being the motto this week as weak fronts continue to affect these Western parts at times especially at first and again later while the East sees a lot of dry and cloudy, benign type conditions in temperatures overall close to if not a little above average.
THE FAX CHARTS The Fax Charts show the current complex Low pressure near Southern britain slowly giving way and filling as a benign ESE flow develops around High pressure to the East. Troughs continue to afflict the West at times even late in the week with occasional rainfall here whereas many Eastern areas become largely dry after tomorrow.
GEM GEM this morning shows a more simplified pattern reolving around High pressure over Europe and/or over Scandinavia. A SE flow will develop across the UK over the coming days and persist through to the end of the run. With pressure rising substantuially this week a lot of dry if rather cloudy weather is likely before pressure falls again towards the end of the run as Low pressure edges in from the west to bring rain back slowly East late in the period.
NAVGEM NAVGEM shows a very similar pattern with the UK under SE winds with the driest and brightest weather in the East while weak troughs continue to affect the West at times with occasional rain spreading further east towards next weekend.
ECM ECM this morning shows High pressure taking over control of the UK weather though it might take a while for the full effects to be shown to all areas as weakening troughs through this week continue to buffer the West of the UK at times. Later on High pressure shifts from being to the East to being to the North of the UK with cooler and frosty air developing in situ under clear skies in the North and a freshening NE breeze across the South where cloud and rain from Low pressure over East France and Switzerland could threaten the SE for a time.
THE ECM ENSEMBLES There is strong support for a shift towards High pressure based weather to develop across the UK around a centre of High pressure which is most favoured to end up centred close to Scandinavia. Weather at the surface will depend on how much cloud is trapped within it's circulation but with a light Easterly drift we have to look towards somewhat cooler conditions with a risk of frost and fog by night in places.
NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend continues to grow towards rising pressure across the UK with a shift towards drier conditions and though possibly cooler never cold.
MY THOUGHTS The models have really shifted away from the unsettled and Atlantic dominated wet and windy pattern shown a few days back to show a cross model agreement on High pressure to the East of the UK affecting all areas with time, though changes in the far West will be slow and erratic and hiccups could give a little rain at times to all areas too as the High pressure shuffles around. there also is some support for a new centre develop near Northern Britain with perhpas more in the way of frost and fog for us if that pattern evolves. However, in the short term a benign east or SE flow will maintain average if not slightly above temperatures but with a lot of cloud likely frost and fog by night looks limited in the short term. The one thing of note this morning is that despite a lot of High pressure around the UK and the NE there is little cold air to tap into but the caveat being that with High pressure in the positions shown a slight drift further North of the High pressure could allow something cold to drift South over Europe and advect West towards the UK. This is hinted at by some output but doesn't develop on this occasion but this could become a feature of the output over coming days if the High pressure support continues to grow between the models. So in the short term some relief from the wet pattern of stalled Low pressure to something not exciting but different in weather terms to look forward to with dry and rather cloudy weather likely to form a large part of many forecasts later this week in temperatures close to or a little above average before falling off somewhat later. At least the water table should start to fall slowly with the impact of less new rainfall becoming significantly welcome.
Martin G
Kilmersdon Radstock Bath Somerset