Good evening. Here is the report on the 12 noon outputs of the regular five model outputs for today Wednesday November 20th 2013.
All models look very similar in synoptic set-up for the next week or so as High pressure settles across the UK and nudges away Low pressure from the SE over the next few days removing the shower risk as it goes. Instead variations in the weather over the next week will be on a much more local scale with varying amounts of frost and fog jostling with otherwise sunny and bright days. Overall temperatures will be on the low side of average with daytime values entirely dependant on whether freezing fog patches form and become resistant to clearance through the day or not.
GFS then shows High pressure persisting across the UK for the majority of the run tonight with only small day to day movements of the position of the centre. Late in the run a temporary breakdown takes place with a period of rain at times in rather chilly conditions with the threat of something rather colder weather persisting with frost and fog at night.
UKMO shows High pressure over Southern Ireland with a moderate Westerly flow over Northern areas. Fog and frost would gradually become more restricted to Southern areas as cloud moves in from off the Atlantic across the North then slips slowly South. Temperatures would be close to average across the North but rather chillier in the South.
GEM tonight, like this morning shows High pressure over the South gradually slipping further South later in the run opening the door to the Atlantic wind and rain moving across the North and then areas further South as a cold front passes. Temperatures will recover to nearer the average at the onset of the more unsettled conditions.
NAVGEM shows High pressure just about holding control over the UK for the next week with the end of the run suggesting more cloud cover and perhaps a little rain as weak fronts cross SE down over the UK. Frost and fog would become rather less of a problem should this evolve and daytime temperatures as a result could approach the average.
ECM tonight shows High pressure either over or to the West of the UK with fine and settled weather but with overnight frost and fog patches to clear away at first each day which could prove problematical at times. The run ends with High pressure still out to the West of the UK and with a colder plunge over Europe the UK could be on the periphery of this maintaining temperatures below average but removing the fog risk with the extra wind flow.
The GFS Ensembles tonight show a sustained period of High pressure over or near the UK with light winds throughout and little in the way of rain shown by most members throughout. Temperatures remain close to average at the 850 level and somewhat below in stagnant surface air.
The Jet Stream remains at high latitudes for the foreseeable future forced North by the presence of High pressure over or near to the UK.
In Summary it's another set of High pressure based model output tonight. It is hard to see anything other than a sustained and prolonged period of quiet weather with light winds, frost and fog at night and some sunshine by day over the coming week to 10 days. As one would expect some cracks in the pattern do begin to turn up late in the run from various outputs but there looks unlikely to be any significant or noteworthy events to mark anything other than a partial breakdown.
Martin G
Kilmersdon Radstock Bath Somerset