Good evening. Here is tonight's account of the 12 noon outputs from the midday outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Friday September 13th 2013.
All models show a rippled front across Southern Britain will move away East overnight with it's heavy rain clearing away East with it. The North already rather drier and fresher than further South and these conditions extend South to Southern areas too tomorrow with some sunshine and light winds. On Sunday all models show a deep depression crossing East to the North of Scotland with a spell of rain and strong winds sweeping East across the UK through the day with gales in the North. By Monday clearer and more showery weather will have swept across all of Britain with some heavy and squally showers for all with hail and thunder possible through the day. On Tuesday another disturbance looks like crossing Southern Britain with another spell of heavy rain and the chance of strong winds before all of the UK return to a more showery regime midweek as Low pressure slips SE down the North Sea.
GFS then shows a steady improvement developing from the SW as High pressure builds in later next week though a complication from an ex tropical storm could return unsettled and wet weather briefly at the weekend as this feature passes across the UK. Thereafter the South sees a lot of dry and bright weather close to High pressure to the South. However, further North and West depressions and fronts passing close by could maintain some spells of cloud and rain at times. It should become somewhat warmer as winds back more towards the SW.
The GFS Ensembles look somewhat different to this morning with considerable variation from day to day. There is alternating cool and warmer phases shown tonight with the operational a particularly prime example showing as a warm outlier towards the end. Rainfall amounts as far as Southern Britain are concerned are lower too than was shown this morning.
The Jet Stream continues to show a strong jet flow across the Atlantic and down over the British Isles from the NW over the coming week or more.
UKMO shows a changeable weather pattern across the UK in the middle of next week with Westerly winds and occasional rain as troughs pass East in the flow but lighter winds by then and probably a little less cool.
GEM tonight also shows changeable weather continuing throughout next week. The cool and windy theme of the beginning of the week does lessen in the second half of the week as the cool flow is eventually cut off as winds back West. GEM also shows the remnants of an ex tropical storm move East over the UK next weekend.
NAVGEM continues to show the Low held up over the North Sea next week with cool and showery weather for all before winds decrease and back towards the West next weekend with less in the way of rainfall in the South for a time.
ECM looks much better too tonight as High pressure is programmed to build from the SW to replace the cool and unsettled spell next week with a much better weekend especially in the South.
In Summary tonight the pendulum has swung back towards a shorter unsettled spell with quiet and standard High pressure based Autumn fayre more likely from next weekend as High pressure is shown with some cross model support to build up from the South or SW with temperatures returning to normal if not a little above in the South. The North though looks like maintaining a more unsettled feel though even here improvements are shown over this morning's output.
Originally Posted by: GIBBY