Good evening all. Here is the report from the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday August 12th 2013.
All models continue to show a similar pattern for the remainder of the week. The NW flow will weaken as a weak ridge crosses East tomorrow but an equally weak warm front will edge East over Central parts tomorrow. On Wednesday another warm front introduces warm and humid air across the UK with some very warm sunshine developing in the SE over Thursday into Friday. the warm fronts may bring a little rain to Central Britain tomorrow and more generally on Wednesday. Then as the humid air takes hold some thundery showers could develop ahead of a cold front crossing SE across the UK on Friday with a brisk Westerly flow following for the weekend with wind and rain advancing from the West as a deep Low develops to the NW of Britain.
GFS then builds High pressure North across the UK early next week with fine, sunny and very warm weather developing over most areas from Tuesday. The weather becomes hot later as the winds turn Southerly with an increasing risk of thundery showers over Southern Britain late in the run.
The GFS Ensembles show the operational was a wild warm outlier in it's second half bucking the trend of the majority of members who keep things rather cooler and closer to what would be normal for mid August. Rainfall events are quite rare with very little overall in the South and decreasing amounts too over the North.
The Jet Stream continues to flow across the Atlantic and the UK for some considerable time before it is shown to move North and become diffuse and light in strength later.
UKMO shows a showery Westerly flow across the UK on Sunday with a Low pressure moving East to the North. The heaviest showers will be in the West through the morning and the East later as pressure rises in the West late in the day. Temperatures will be rather cool , especially in exposure to the fresh West wind.
GEM tonight shows a cool and breezy weekend with heavy showers. then through the early days of next week High pressure builds up from the South with increasingly warm and sunny weather extending to most areas by midweek. Towards the end of the week it becomes hot in the South and East with only a little cloud and rain in the far NW.
NAVGEM shows High pressure slowly building across Southern Britain early next week but looks like struggling to extend far enough to reach Northern areas where cloud and a Westerly breeze could still bring some occasional rain while the South becomes dry and bright and warmer.
ECM tonight also shows High pressure building across Britain early next week. The centre holds to the SW of the UK keeping the warmest weather over the continent and keeping the UK under broken cloud and sunny spells and light winds and mostly dry weather.
In Summary there is still some strong signals from different outputs of High pressure building up from the SW early next week following a blustery and showery weekend when temperatures are held at normal values or just below. There are though some opposing signals that High pressure might not be quite so keen on building right across the UK which would keep warmer conditions at bay. However, whatever happens it is unlikely there is going to be any significant rain once we pass the Low pressure blip at the weekend.
Martin G
Kilmersdon Radstock Bath Somerset