Good evening folks. Here's my evening attempt to disect the 12 noon outputs from the NWP for today Friday December 27th 2013.
All models shape a broadly similar pattern between now and New Year with the deep depression close to Northern Scotland filling and moving away slowly North tonight and tomorrow. In it's wake lies a showery WSW flow with the most showers in the West and near the coasts with some lengthy dry spells in the East. Later on Sunday a new trough moves in from the West with another band of wind and outbreaks of rain for all areas over Sunday night returning to sunshine and showers on Monday. On Tuesday Low pressure close to the West sends a new spell of rain and strong winds NE across all areas with New Years Day seeing much more of the same mix of outbreaks of rain and showers in brisk SW winds and temperatures close to average.
GFS then shows the post New Year period with a sustained windy and unsettled picture as Low pressure continues to be shown crossing the UK or within the proximity with unrelenting spells of rain and showers in average temperatures. Late in the run pressure is shown to build down from the North or NE and allow troughs from the West to come up against a tongue of colder air over and to the NE of Britain meaning a much increased chance of a break in the Atlantic train to something which could see some places receiving some snow at times in much colder air as mild Atlantic troughs come up against this colder air.
UKMO tonight closes it's run next Thursday with Low pressure out to the NW with a cyclonic SW flow over Britain carrying troughs NE overall areas with rain, heavy at times in brisk SW winds.
GEM shows a trend towards something colder too later as pressure builds over the Arctic and forces Low pressure areas further South and sends them SE over Europe. On this run the UK is in the battleground area with rain coming up against cold air over North and East Britain and potentially giving rise to some snow for some.
NAVGEM unavailable tonight
ECM shows a mobile Atlantic flow as Low pressure continues to pass Eastwards over or to the North of he UK with rain and showers for all in sometimes very windy conditions and temperatures close to average.
The GFS Ensembles remain uninspiring for cold fans as the vast majority of members still maintain a very active Atlantic sending frequent bands of rain across Britain in average temperatures. The colder outcome of the operational member was not supported by hardly any of it's colleagues but shouldn't be discounted as it has some support from GEM later.
The Jet Stream shows a much more mobile pattern as it continues it's unrelenting path across the Atlantic towards Southern Britain and on to Europe. It does show strong signals of sinking further South over Europe through Week 2 and this may involve sinking the flow a little way South of the UK too.
In Summary there is still a lot of support for the mobile Atlantic and sometimes stormy weather type to continue with spells of rain and showers along with temperatures close to average. However, there are a few grains of comfort for cold fans as the GFS operational and GEM shows some build of pressure to the North and NE late in their runs but they look very much in isolation at this stage. Having said that from small acorns big oak trees grow so if these rogue signals increase in frequency between the output in the days to come and gain more cross model support then they might be taken more seriously.
Martin G
Kilmersdon Radstock Bath Somerset