Good morning. Here is the report on the 12 midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Tuesday October 8th 2013.
All models show the same pattern that's been shown for some time now. After a sustained period of above average temperatures across the UK things are set to change as a couple of cold fronts move South through Britain today and tomorrow. Pressure then rises to the West and NW of Britain with a chilly and strong Northerly flow developing, especially in the East where showers will be heavy and prolonged in places on Thursday before the risk of these becomes restricted towards more Southern and SE areas by the weekend as High pressure builds back NE over the North. Away from the South and East the weather will become dry and bright with clear or sunny spells and temperatures on the low side with frost and patchy fog possibilities at night.
GFS then shows next week as becoming more changeable and sometimes windy after a short spell of higher pressure has collapsed over the UK by midweek. Thereafter rain at times moves in off the Atlantic in association with Low pressure areas moving NE across the UK. Temperatures would be close to average though rather chilly in the wake of cold fronts having passed through.
UKMO today continues it's approach to more modified influence from Low pressure to the SE at the weekend, filling it up and leaving a spell of slack winds and pressure to start next week with a lot of dry, cloudy and probably misty weather with the risk of a shower almost anywhere.
GEM today shows most Southern areas of England and possibly South Wales cool and showery at the weekend before these conditions ease to quiet and rather cool weather at the surface with a lot of cloud and mist around. Later in the run the trend is for Southerly breezes to develop with occasional rain moving in from the West towards or over the South and West later.
NAVGEM shows a more meaningful attack from the Low pressure over the South of England at the weekend with most Southern areas seeing rain or showers at times in rather cool conditions while the North stays dry and bright if cool. At the end of the run this drier and benign weather extends South to all as a weak ridge of High pressure ridges down from the North with light winds and mostly cloudy weather but foggy if skies clear by night.
ECM this morning shows the showery Low near the SE at the weekend filling up to allow the ridge of High pressure in the North to extend South to all with fine and dry weather for all when there will be a lot of cloud, mist and fog or all three in temperatures just about scraping to average values if conditions brighten. Late in the run fronts approaching the SW could bring a little rain into these parts later before High pressure returns on Day 10 killing any rain and returning the UK into fine and quiet weather with fog looking likely to ebcome a major issue later next week should this pattern evolve.
The GFS Ensembles this morning indicate an unsettled spell to come from this weekend with some rainfall for all areas at times for the rest of the run. The operational run was one of the drier members with some members opting for more Low pressure dominance with most members showing average temperatures in the second half of the run once the influence of the cold Northerly has been lost at the weekend.
The Jet Stream Ensemble forecast this morning shows the flow to the North diving South over the UK today and tomorrow to the East of which forms the Low pressure near the SE. This circualtion draws a new arm of the Jet towards in and begins a spell when the Southern arm of the Jet crosses the Atlantic well South of recent positioning.
In Summary today the pattern shown over yesterday is maintained this morning. There are variances on how much influence the Low to the SE affects the weather in the South at the weekend with UKMO showing very little spread while GFS and NAVGEM are more bullish in potential wet weather in the South. Meanwhile the North look more guaranteed to stay dry if rather chilly with some night frost and fog. Next week looks fairly benign as what's left of the Low near the SE fills up leaving a legacy of cloud and mist across the UK in very light winds. In the outer limits the Atlantic does look at least interested in playing a part in our weather later in the month but there looks nothing distinctive about this at the moment with only the South and West likely to see some rain from this scenario. However, GFS does show much more push from this supported greatly by it's ensembles with all areas seeing some rain too later next week. Whatever happens all models share the fact that the unseasonably warm weather of recently willbe a thing of the past after today with much more average and at times below average temperatures more likely with some fog and frost issues if skies clear by night. having said that there seems little sign of anything desperately cold to excite folks as yet.
Transcript taken from:-http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm
Martin G
Kilmersdon Radstock Bath Somerset