Good evening. Here is tonight's viewpoint from me on the midday outputs of GFS, UKMO, GEM, NAVGEM and ECM for tonight Thursday September 12th 2013.
All models maintain the pattern of weather now up to and including Tuesday of next week. The next 24-36 hours will see an array of fronts cross all of the UK tonight and across the South later tomorrow as a wave depression runs East across Southern England late tomorrow. This will bring outbreaks of slight to moderate rainfall but with some heavier bursts possible here and there especially in the South later tomorrow. Once this clears early on Saturday a respectable period of weather will occur with some sunshine and light winds. However, this is the lull before the first Autumn gale of the season which batters the North on Sunday with troughs sweeping East across all areas with widespread rain, heavy in places. Following a squally cold front SE Monday will be a very windy day for all areas with squally, heavy and thundery showers likely almost anywhere but most frequent in the North and West. On Tuesday Northern areas see another showery day while Southern areas see another small but vigorous trough feature run East across Southern England through the day with a spell of more prolonged rainfall before a return to squally showers in NW winds ends the day.
GFS then shows further disturbances running SE across SW Britain through the remaining days of next week with further cool and rainy weather here at times while the North and East seem more likely to stay rather showery but all areas stay very cool. Later in the output the South becomes drier and brighter for a time as a ridge to the South edges into Southern Britain for a time. However, the North stays breezy and changeable with this windy and changeable theme extending back South across the rest of Britain late in the run.
The GFS Ensembles tonight show a period of rather cool weather with good consensus between the members of cool and changeable weather with rain at times for a good part of the run. Some drier spells look probable at times but Low pressure looks likely to hold sway over the UK with at least some rain and strong winds for the UK, even in the South.
The Jet Stream shows the flow moving East to the North of the UK over the next few days before it dives SE on a very strong flow through much of next week and even shows little sign tonight of leaving the UK continuing to blow from the West or NW for the next 10 days or so.
UKMO tonight shows Low pressure moving SE over the North Sea with a very showery NW flow following a very strong taste of Autumn in the way of wind and rain in the days before. With High pressure showing rising heights to the North of the UK it looks like further Low pressure crossing the Atlantic later next week could have the UK in it's trajectory.
GEM shows a very windy and unsettled week throughout next week before the emphasis on the most changeable conditions shifts to the North of the UK with generally less wind and rain in the South later in the run as High pressure edges somewhat closer to the South.
NAVGEM shows a very deep Low trundling down the North Sea early next week with the centre making it's home somewhere near Denmark late in the week pulling down continually cool or very cool and showery North or NW winds with the final day's charts showing further Low pressure moving across the Atlantic towards the British Isles at the close of the run.
ECM tonight shows an extended cool and unsettled spell through next week and possibly beyond with showers or longer spells of rain and very cool NW or North winds as High pressure over the Arctic forces the Jet South over the UK with the UK in the firing line for a succession of depressions running through on a brisk and cool West flow though conditions warming a little late in the run.
Tonight's Summary can best be described as a typical Autumn one with all models hardening their grip on the prospect of a very early taste of cool and potentially very windy weather next week when showers or longer spells of rain remain the order of the weather through the week. The prospect of High pressure building NE across the UK shown by previous output is looking a little less certain tonight with more members going for a continuation of changeable conditions albeit with something slightly less cool developing with time as winds become more westerly but still fresh to strong at times.
Martin G
Kilmersdon Radstock Bath Somerset