Good morning folks. Here's how I see the 12 midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday December 11th 2013.
All models show a slack Southerly flow with a continental influence in the SE making for a foggy start for many with a touch of frost under clear skies for others. Elsewhere the air will be maritime and milder with a lot of cloud and some rain in the far NW. Through tonight cloud will extend East to many areas and troughs will begin to make headway across the British isles from tomorrow changing the weather to more changeable with rain at times, principally on Friday and Sunday with a colder and drier interlude lasting through Saturday as a ridge crosses by from the West.
GFS then shows all of next week with Low pressure out to the NW and troughs rushing NE across the UK in a strong to gale force SW flow. rain at times would occur everywhere and it could be very wet in the NW with copious totals through the period over hills and mountains. There will be less rain in the SE at first though even here towards the end of the run it will become very wet and potentially stormy at times as we move towards Christmas. A white Christmas looks unlikely away from Scottish mountains due to temperatures being near to or above average throughout.
UKMO closes it's run today showing a Low pressure trough swinging East across the UK next Tuesday with some rain and wind for all before clearer and colder conditions temporarily spreads in from the West through the day.
GEM is similar on Tuesday before an intense Atlantic depression spawns some powerful Low pressure areas which zip NE across the heart of the UK later with rain and storm force winds at times followed by squally showers on a strong Westerly breeze. Though technically quite mild in would feel cold in the strength of the wind and rain which in itself could be copious at times.
NAVGEM this morning shows Low pressure well to the NW in a week's time but with a strong SW flow over the UK ahead of a squally trough moving it's way slowly SE across the UK through next Wednesday. It would remain mild for many through the day.
ECM offers very changeable conditions next week with spells of strong and mild SW winds alternating with brighter and drier interludes when it would be briefly less mild. Overall the heaviest rain would be to the NW with the longest dry spells towards the SE.
The GFS Ensembles today show complete support for a relatively mild and unsettled spell to commence this weekend and last until Christmas at least. With winds often strong and from the SW the wettest weather will be in the North and West but even the SE will see some heavy rain at times if this run is to verify.
The Jet Stream remains very strong throughout the run and maintaining it's NE orientation firstly located NW of Britain but moving further SE over the UK and on towards Scandinavia next week keeping the UK under the influence of mild and string Atlantic winds throughout.
In Summary today there is an unsettled spell on the way. As the High to the SE migrates further away several hundred miles the UK is able to tap into more in the way of Atlantic mobility and aided by a powerful Jet Stream there is the potential for some powerful storm systems to develop over the North Atlantic and the North of Britain over the period. Details differ between the output but the general message is plenty of wet and windy weather to come with the usual caveats that the heaviest rain will be in the North and West while the SE sees the best of any drier interludes while all areas are at risk of gales, severe at times. It will remain generally mild though a few days of colder weather may be thrown in at times behind cold fronts when temperatures return to average briefly.
Martin G
Kilmersdon Radstock Bath Somerset