Good morning. Sorry no report last night but too busy with work. However, here is todays account of how the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM look for today Sunday December 1st 2013.
All models show a large annticyclone close to Ireland with a gentle Northerly flow over the UK. A lot of cloud is trapped under this HIgh pressure and will continue to dominate conditions over most areas for the first few days of the week with limited brightness and just a little overnight frost and fog if skies happen to clear somewhat overnight. By midweek most models show High pressure weakening slowly and allowing a weak cold front to slip South on Wednesday with a little rain travelling North to South over all areas. This is then followed by another one on Thursday, this time more marked with a switch to cold and strong NNW winds with wintry showers travelling South all the way down to Southern England by Friday. Frosts would return at night and snow showers would be falling thick and fast across some Northern and Eastern areas at times with even a few possible in the South for a time. Through next weekend all models illustrate High pressure moving in close to the South of the UK with the Northerly flow becoming cut off with a legacy of cold air over the South with clear skies giving rise to sharp night frosts and freezing fog patches while the North becomes less cold as winds settle from the West with more cloud spilling in too.
GFS, in Week 2 shows High pressure moving away SE into Europe and allowing all areas become under the influence of an increasingly mild and strong SSW flow with Low pressure spiralling around in the Atlantic sending troughs towards the North and West with rain at times, though amounts in the East and SE would be small or non existent at times. At the very end of the run ssomewhat colder air may reach Southern and Eastern areas as a SE continental drift to the wind reaches these areas.
UKMO today closes it's run next Saturday showing High pressure over Western Ireland with a decreasing but still very cold straight Arctic Northerly flow over the UK delivering snow showers to Northern and Eastern coastal areas in particular, all the way down to Essex and Kent. The West would become largely dry but cold with sunny spells and overnight frosts.
GEM sinks High pressure away South from late next weekend and into the second week with a strong and less cold Westerly flow developing for all with rain at times too, chiefly but not exclusively in the North and West with average vlue temperatures by midweek.
NAVGEM holds High pressure over the UK with a centre much further NW towards Greenland with a ridge SE across the UK. The end of it's run would be typified by very cold and frosty weather with snow showers dying away from NE areas apart from the far NE coast. Some sunny days would probably compensate for the very cold conditions.
ECM today shows High pressure holding firm across Southern England having arrived here next Sunday. The North would slowly become less cold following the cold snap and a lot of cloud would encompass these areas off the Atlantic with little in the way of frost and fog then. These benign conditions will gradually extend South to Southern Britain too by the middle of Week 2 replacing the frost and fog patches of early in the week.
The GFS Ensembles shows good support this morning for a short cold snap late this week and coming weekend to be followed by a NW/SE split in the weather with a long fetch SW'ly looking the most likely option. All areas would be at risk of some rain at times, only a little at times in the SE but with some wetter conditions to the North and West along with strong winds and temperatures everywhere recovering to above average.
The Jet Stream shows the flow tilting to a more SE direction later this week down across the UK from it's current location which is well North of the UK. It then resets in a NE directions across the Atlantic and across Scotland through Week 2 indicating Low pressure to the NW and High pressure to the SE of Britain.
In Summary the weather is set to turn colder briefly at the end of this week and next weekend with some snow possible for a time in the North and East and sharp overnight frosts in the cold North wind. In the meantime the weather will stay cloudy and benign with dry weather until a couple of weak fronts deliver the cold snap soon after midweek. Then through Week 2 it's all about where the High killing off the cold North feed ends up. The Americans seem to want to sink it SE over Europe quite quickly next week setting up a changeable and relatively mild and breezy SW feed with rain at times, mostly in the North and West while ECM shows High pressure holding across the South with a return to benign and increasingly cloudy and less cold conditions following a frosty start to the week. Which is right? It's a case of more runs needed I'm afraid.
Martin G
Kilmersdon Radstock Bath Somerset