Good morning. Here is my interpretation of how and what to expect weather wise from the midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Friday July 26th 2013.
All models show low pressure to the West of the UK with a light Southerly or SE drift over the UK. Many Southern areas will see dry and fine weather over the coming 24 hours while the North sees further heavy and sometimes thundery showers. Through tomorrow an area of Low pressure will move North from France over England with spells of thundery rain moving North too with thunderstorms embedded in places particularly in the SE. As the South moves on the Southern flank of this Low later in the weekend cooler and fresher air will move across from the West with brighter and breezier conditions with scattered showers. Through Monday and Tuesday the weather is shown to become cooler and fresher for all as winds settle SW with showers at times and the occasional longer spells of rain too here and there.
GFS then shows further unsettled weather through the remainder of the week, especially in the North and West while Southern and Eastern parts may become rather warmer and drier again for a time before a cold front brings thundery rain across from the West at the weekend and a return to fresher air once more. Later in the run the trend towards warmer weather is shown again as a High pressure ridge over the North develops drier weather there while areas in the South see thundery Low pressure from the Continent bring outbreaks of thundery rain, clearing later as warm High pressure rebuilds from the SW at the end of the run with attendant fine and warm conditions by then for all away from the far NW.
The Ensemble data from GFS shows a variable pattern of temperatures in the South for another week often bordering warm before the South joins the North in a basic Westerly regime with average temperatures and rain at times.
The Jet Stream shows the flow blowing NE across the South of the UK from Biscay for some time to become before the trend evolves to send it on a West to East course across Southern Britain in Week 2 of the output.
UKMO today has a showery SW flow midweek before it opens isobars out to give a slack period of weather with light winds and thundery showers in the North while Southern parts see a lot of dry weather. The SE close to the still hot conditions over Europe would remain under risk of pulses of thundery rain moving NE close to the coast on occasion.
GEM today shows very warm air extending North midweek at the same time as Low pressure moves into it from the West. The potential for heavy, thundery rain is there for many with very warm and humid weather extending on through the weekend with the risk of thunder sustained as further Low pressure edges into the hot air over the UK from the SW over the weekend.
NAVGEM is less dramatic with a generally NW/SE split developing next week with most of any rain in the North and west while the South and east see lengthy periods of dry, bright and quite warm weather with just brief flirtations with rain as an occasional front edges over from the West later.
ECM this morning shows a warm up across the UK midweek with Low pressure to the West edging in giving rise to the potential for further thundery rain or storms late next week before cooler, breezier and fresher air follows behind the depression later. The end of the run shows a cooler NW flow in the wake of the Low bring a day or two of cooler, showery weather before the end of the run raises optimism on a return to warm High pressure in the period immediately following the end of the run.
In Summary details are very different between the models this morning once we get through the mostly agreed pattern of events over the coming 5 days or so. So after the warmth and potential thundery weather of the weekend has passed a cooler phase looks likely with showers. Beyond that the output is varied with some output quickly bringing warm weather back across Britain with further thundery incursions at times while other show a more Atlantic dominance with rain at times in cooler westerly winds. Personally I feel that warm weather is never going to be far away from many Southern areas over the coming weeks given that the Continent remains very warm for a long while to come. It's all a matter of how the cooler Atlantic air always present on this morning's runs interacts with any warmer weather fed up from Europe. The result of such an interaction could result in copious thundery rainfall on occasion most likely towards the SE. Of course less interaction will mean the majority of rain stays in the North and West with the most pleasant conditions towards the SE. Forecasting these small differences in synoptics could be very difficult over the coming 10-14 days and only possible at short range but could have major implications on events at the surface.
Originally Posted by: GIBBY