Good evening. Here is the report on the midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Thursday July 25th 2013.
All models show a slack Southerly flow over the UK in association with Low pressure West of the British Isles. A basic showery pattern is shown with most of the showers in the North. Then on Saturday a large area of thundery rain moves North out of France with thunderstorms, severe in places. The question is how far West into the UK this comes with some output just suggesting SE England and East Anglia affected while some other output brings it further West into Central Southern England and the Midlands as well as the Eastern part of the west Country and SE Wales. By Sunday the pattern simplifies as somewhat cooler and more showery conditions move in from the West behind it with some sunny spells in between, a pattern that then lasts well into next week with the heaviest showers in the North and West.
GFS tonight shows Low pressure winding up from the SW by late sunday with the early part of the week windy and unsettled with rain then showers moving NE over Britain. Then after several days of average temperatures and rain at times warm weather develops again in the SE with humidity on the rise and thundery showers returning to SE areas by or over the weekend. Longer term changeable weather returns to all with temperatures returning to the seasonal average in broadly Westerly winds.
The GFS Ensembles fluctuate a lot in the South over the coming week as warm uppers engage with cooler Atlantic air with varying degrees of success in week. Agreement then firms up on a spell of cooler more average temperatures with rain at times thereafter.
The Jet Stream continues to show a more Southerly aspect to it's flow over the coming few weeks. For the first week the flow turns NE over the UK and around the top of the hot plume over Europe before a more definitive West to East push develops across the Atlantic, Southern UK and Europe later in the run.
UKMO tonight keeps Low pressure close to NW Britain midweek with a sunshine and shower mix continuing across the UK with temperatures holding well up to average or slightly above.
GEM tonight shows a showery start to the week before Southern areas become warmer and more humid again for a time before a return to cooler and somewhat unsettled conditions late in the run especially affecting the North and West with some longer drier spells still in the SE.
NAVGEM maintains Low pressure to the West or NW of the UK throughout though it does migrate as far away as Iceland later in the run with any rainfall by then in the SE not very noteworthy with temperatures close to or a little above normal overall.
ECM tonight looks quite unsettled next week with rain at times as Low pressure moves over or close to the UK. With fresh winds blowing from the SW much of the week the weather will become cooler everywhere. The rain will come in bands interspersed by showers, heavy in places. The end of the run keeps things fairly unsettled and showery with slack Low pressure continuing to be centred close to or over the UK.
In Summary there is still a lot of support for the UK to lose a lot of the very warm conditions after the weekend with temperatures returning to average along with the typical Summer mix of sunshine and showers in mostly SW winds. However, warm air resists moving far away from the near Continent and could infiltrate SE England at times with the risk of some thundery rain too while most other areas stay unsettled and cooler with rain at times.
Martin G
Kilmersdon Radstock Bath Somerset