Good morning. Here is the report on the midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Wednesday July 17th 2013.
All models show a fine and very warm or hot period still to come with at least 5-6 days more of fine weather still to come before some changes begin to take place. High pressure will remain centred over the UK with very warm uppers over the UK and the persistent cloud and drizzle in the far NW should finally move away North soon. As always in hot weather there is always the chance of the odd thundery shower at anytime in the heat of each day but these will never be a widespread feature over this period. Later in the weekend as the High drifts further north cooler and more cloudy conditions could begin to move into Eastern and central parts from the East.
GFS then shows next week as a week when pressure slowly leaks away over the UK as the high pressure becomes less defined with a slack flow allowing some thundery showers to become more prevalent later in the week though temperatures will remain very warm for many. Through next weekend and the further outer reaches of the run the weather looks like it could finally break down with rain at times and rather cooler air feeding in from off the Atlantic as Low pressure begins to take more control.
The GFS Ensembles shows a more definitive indication that cooler weather may move into Southern Britain around the 26th-27th. There is in the meantime plenty more hot and sunny weather to come before Low pressure makes inroads from the Atlantic with outbreaks of rain, innitially thundery and cooler air following from the West.
The Jet Stream shows the flow maintained to the North of the UK for another week at least before indications suggest it may move South towards the UK in Week 2 albeit never particularly strongly.
UKMO this morning looks very warm and humid to begin next week with High ressure having become less defined and located near Norway with a slack windflow across the UK and pressure having fallen somewhat. There will be a lot of dry weather still to be found but the risk of thundery shwers will be increasing with time almost anywhere.
GEM shows much more diffuse methods of bringing any changes across the UK with the basic message being that a few thundery showers early in the week will lead to a North/South split in the weather later in the run with some cooler and somewhat unsettled conditions likely in the North while the South stays dry and bright with some warm sunshine still.
NAVGEM shows a trend towards cooler and potentially more showery weather later next week though the South and West would see very little rain as High pressure remains dominant to the SW of the British Isles.
ECM today shows that pressure leaking way next week will result in a lot more cloud, very warm or hot weather in the first half of the week but with some well scattered but heavy and thundery showers around too. later in the week cooler weather looks likely with showery rain in places as a cooler NW drift develops over the UK.
In Summary there is some shift this morning to somewhat cooler and more showery weather looking likely to develop at some stage next week. Whether this is the catalyst for a more definitive breakdown in the very warm and hot spell remains to be seen at this early stage and it maybe that many places stay dry and very warm for much of the time. Any rainfall looks scattered but potentially heavy and thundery with light winds continuing to be a feature over the UK. Despite all this talk about rain and cooler air there is no major weather events shown in the outputs today with changes local and probably temporary for many with reasonably warm and dry conditions still holding balance over the UK as a whole.
Martin G
Kilmersdon Radstock Bath Somerset