Hi folks. Here is today's report on the midnight outputs of GFS, UKMO, GEM, NAVGEM and ECM for today Monday July 29th 2013.
The General Situation. All models show Low pressure to the NW of the UK with a showery SW flow over the UK. This situation is maintained for the next 24 hours before a waving frontal feature moves up into Southern Britain tomorrow with occasional rain. This then is shown to extend North across Britain through midweek followed by an increasingly warm and moist SW then Southerly flow through the remainder of the week. A weak cold front will lie close to western Britain by the weekend with a plume of thundery weather likely to affect the SE late in the week and for a time at the weekend with thundery rain or storms.
GFS then shows slightly fresher weather for a day or two as the weak cold front crosses East displacing the very warm conditions for a time. Through the following week High pressure builds East from the Atlantic with increasingly settled and warm conditions developing with long sunny spells and dry conditions for all. Later still the fine and by then hot conditions will be tempered by a migration of cooler and more unsettled weather gradually working its way in from off the Atlantic.
The GFS Ensembles still show the sharp rise in uppers later this week. Thereafter the operational I have described above is a wild warm outlier with nearly all of the other members preferring something much cooler and nearer to average for early August with occasional rainfall.
The Jet Stream continues to be pumped NE across the UK and towards Scandinavia over the coming days and becomes weaker later as it tilts on a more West to East flow across the vicinity of the UK next week.
UKMO today shows a SW flow over the UK at the start of the weekend with some showers in the North and West. Although the very warmest of the weather will of left the SE it will still be reasonably warm and likely to become dry as High pressure builds to the South of the UK.
GEM today shows a slightly fresher weekend as the very warm air is temporarily displaced from the SE early in the weekend. As we move into next week the trend for warm and humid weather increases as a ridge builds towards the NW from an Atlantic High and Low pressure develops over NW Europe with some thundery rain or showers breaking out in the south and east in particular for a time.
NAVGEM also shows a SW flow at the weekend with Low pressure up to the NW. Scattered showers would be likely for most Northern and western parts while the South and East could escape with quite a lot of dry, bright and reasonably warm conditions.
ECM this morning shows a build of pressure at the weekend and having displaced the hot air at the end of the week from the SE our own home grown heat develops as a small High develops over England. This becomes quickly removed as more humid and thundery conditions develop in response to a strong build of pressure to the NW with a thundery Low just to the South of the UK at the end of the run with showers and thunderstorms in the South and east and hot conditions for the SE.
In Summary today there is a growing trend to build High pressure from the Atlantic early next week probably towards the NW which could promote another period of warm or very warm conditions for parts of the UK should it evolve. Current projections show it not too last too long before thundery weather breaks out though warmth could still be maintained with high humidity levels. Discounting the GFS operational this morning in it's isolated form may not be as far from the pattern balance as it might first seem as it does include some support from the other models. The one clear message from this morning's runs are that the weather is going to maintain itself on the warm side of average with the continuing chance of thundery weather particularly towards the SE and some fairly decent and useable weather at times for nearly all of the UK.
Martin G
Kilmersdon Radstock Bath Somerset