Good morning everyone. Here is my interpretation of the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Sunday December 8th 2013.
The General Situation. All models show a pattern of High pressure over France with a Westerly flow of winds across the UK, strongest in the North. Through the coming week the trend will be for winds to back more towards the SW and then South with even milder air affecting the North and West in particular through the coming week with some further rain at times towards the NW as Atlantic fronts brush by. In the SE there are still some signs that it may be a little less mild than elsewhere with a drift off the Continent for a time midweek and mist and fog could be present on some nights between now and Thursday. Towards the end of the week though High pressure remains stubbornly to the SE and mild SW winds will affect all areas with further rain in the NW which may extend further SE next weekend in what could become very windy weather in the NW.
GFS then shows next weekend as windy and mild with rain at times. This extends into week 2 with the trend for winds to veer more towards the West and later NW drawing colder air South and East across the UK behind successive depressions and cold fronts with temperatures returning to normal and a little below in the North. With rain at times likely for all by then some of this will fall as snow over Northern hills before the end of the run.
UKMO for next Saturday maintains High pressure down over SE Europe with a broad and mild SW flow over Britain with troughs out to the West delivering some rain to the North and West of the UK while the South and East remain largely dry but cloudy.
GEM today keeps High pressure over Germany next weekend very much in control with just local variations on temperatures and cloud cover the only likely items of interest in an otherwise benign pattern. The High does show signs of weakening for a day or so before intensifying again near SE Britain at the end of the run with a renewed period of fine weather but maybe a little colder with mist and fog possible in light winds.
NAVGEM is resilient to showing any major changes either as it ends it's run with mild SW winds bathing the UK in dry and rather cloudy weather though a rogue weak trough could deliver a little rain for a time next weekend and rather more frequently over the NW.
ECM does also show a rather windier spell for all next weekend but still potentially very mild in a strong SW breeze. Occasional rain could occur almost aywhere as weak troughs pass NE but this becomes restricted to NW Britain later as High pressure remains in total control stretching in a belt from the Azores to Southern Europe by early next week and lockning the UK in a mild SW flow for some considerable time to follow Day 10 if verified as shown.
The GFS Ensembles this morning show little change to that being shown in previous runs. There seems little support to exit the UK out of this locked pattern of mild SW winds which only slowly lose their very mild uppers status late in the run. However, a drift to average upper levels is unlikely to make much difference down at the surface as SW winds just become more unstable with rain at times for all likely later with winds still blowing for the most part over the UK from a mild Atlantic point.
The Jet Stream this morning remains at odds with delivering cold weather with the flow running NE strongly between Scotland and Iceland. Over the coming week this flow moves even further North for a time before the continuing trend to slip it back further SE to be crossing NE over the UK in Week 2. It's orientation does change slightly late in the run to a more direct East flow over Britain as High pressure collapses over Europe and relocates near the Azores, Southern France and Spain.
In Summary this morning there remains little sign of change in conditions over the UK for the next few weeks. In such conditions it is unlikely that anywhere above mountain top location will see a white Christmas this year if this morning's charts verify. The UK seems locked in a South or SW flow with High pressure persistent over SE Europe bathing the UK in potentially very mild and cloudy air. Some local low level cold inversions may affect the South briefly midweek but other than that cold remains on hold for now. Rainfall amounts will be small in the South though the NW could see quite a bit of rain at times as troughs brush past in a strengthening SW flow here later in the week. There are then small signs of this sinking SE to affect many areas through Week 2 with rain at times for all should it occur but it looks unlikely that such a change would result in anything very wintry soon afterwards as High pressure is shown remaining locked strongly over Southern Europe and the Azores.
Martin G
Kilmersdon Radstock Bath Somerset