Good morning. Here is my view of the midnight outputs supplied by GFS, UKMO< GEM, NAVGEM and ECM for today Friday August 2nd 2013.
The General Situation. All models show a warm and moist SSW flow over the UK being replaced by a cooler and fresher SW flow following a cold front East across the UK today. The showery flow lasts through the weekend before an active frontal system approaches the SW later on Sunday and ambles it's way NE across the UK on Monday. The rest of the week is then dominated by the legacy left behind by this feature in the shape of a slack and benign spell of light winds and showery conditions lasting pretty much out to next weekend. There are small differences in the specific pressure pattern shown between the models through the week but they all point to a very similar weather type at the surface with just differing opinions on the location of the most showers from day to day in a week that will see temperatures very close to the seasonal average.
GFS then progresses on through next weekend with a developing Westerly flow with fronts crossing East over the UK attached to Low pressure North of Scotland. The most rain will be in the North and the South may be dry if rather cloudy for a time at the weekend before a larger surge of Low pressure tightens wind strengths and digs rain down further South over the UK towards the middle of the week and again the following weekend with showers in between.
The GFS Ensembles show tight support for a period of very average temperatures and rain at times driven in by Atlantic winds later and slack, cold pool showery type conditions in the first half of the run.
The Jet Stream continues to be shown to blow across the UK in one shape or form for the duration of the output. It does undulate North and South at times especially early in the run though any signs of a migration to a better position well North of the UK looks unlikely at the moment.
UKMO today closes it's run with a slack and cool Northerly flow over the UK. there would be some warm sunshine to be felt in the light winds but some large slow moving daytime showers and thunderstorms would be likely in places.
GEM today keeps the showery theme too next week though there are hints of a drier and warmer spell towards the end of the week over more Southern areas of the UK, albeit briefly.
NAVGEM this morning shows this improvement too with it's reach extending across much of Britain for a time in the shape of a ridge of high pressure. This means the showers would largely die out by next weekend with some warm sunny intervals for many and dry weather too with the temperatures nudging up for a time in the South at least.
ECM shows a showery first half of the week before a ridge brings a drier and brighter interlude on Thursday before Atlantic fronts attached to a depression to the North spreads wind and rain through most areas. the rain would be heaviest in the North and the South may not see much from this. By the weekend winds are shown to turn towards the NW bringing clear and clean air SE across the UK with a mix of sunshine and showers, heaviest in the North. On Day 10 there is a hint with the Azores High having shifted slightly further North that the following days would see the weather settle down and warm up slowly from the SW.
In Summary the models are trying desperately hard to bring fine weather back into the UK at some point later next week. Until then it's full support from all models on showery conditions at best with some longer spells of rain too early in the week and temperatures close to average. GFS then offer an almost 'no hope' situation with it's turbulent run of westerly winds in Week 2 in it's typically progressive long term patterns. Some of the other output does show at least a glimmer of light though with GEM, NAVGEM and ECM offering ways out of the cooler and unsettled conditions towards next weekend or soon after. Whether this is just a glitch or the start of a new trend of change will remain to be seen in future output.
Martin G
Kilmersdon Radstock Bath Somerset