Hi everyone. Here is todays account of the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday December 16th 2013.
All models show an unstable and relatively mild SW flow across the UK. This slackens off over the next 24 hours as a series of troughs finally clear the SE tonight. Then a 24 hour or so window of dry and bright weather with clear spells by night could give rise to the only frost of the week tonight in the North. Late tomorrow and Wednesday a new Atlantic storm winds itself up to the NW carrying renewed gale or severe gales to parts of Britain with rain sweeping East on Wednesday with colder and more showery air on Thursday when wintry showers could affect the North. On Friday, windy and milder air will return with more heavy rain with a rinse and repeat pattern of rain followed by showers looking likely over the coming weekend.
GFS then shows the run up to Christmas as unsettled and windy with rain at times. Conditions will be relatively mild in the South but colder at times in the North with wintry showers in between the spells of wind and rain. Christmas itself will be very windy and stormy across the NW as well as becoming generally rather less mild. Periods of rain look likely on Christmas Eve and Christmas Day followed by squally wintry showers across all areas later on Christmas Day and Boxing Day with gale force Westerly winds. The final days of the year are then typified by further rather cold and unsettled weather with an increasing risk of snow at times in the North as winds turn more NW'ly towards the New Year.
UKMO today ends next weekend on a windy and rainy note with an active and squally cold front crossing East next Sunday with heavy rain followed by rather chilly and showery WNW winds by night time.
GEM today shows High pressure building over Eastern Europe next week with winds backing Southerly or even SE'ly towards Christmas. With Low pressure ganging up to the West the Southerly flow would be very unstable with heavy rain moving North across Britain and more slowly East in temperatures close to average.
NAVGEM keeps strong WSW winds over the UK in the run up to Christmas with spells of rain alternating with showers, wintry in the North.
ECM keeps things very mobile and stormy at times with Christmas Day looking very worrying as an unusually intense Low near the Hebrides through the Day would bring damaging storm force winds to the West and NW in a spell of very heavy rain followed by squally and wintry showers before things moderate somewhat over Boxing Day.
The GFS Ensembles show a very turbulent period of weather over the next few weeks taking us through Christmas and up to the New Year. There is plenty of rain shown by most members throughout the period with the pattern having changed little 14 days from now. There is no indication of any fall off in uppers to levels that would give us anything more wintry to look at though in the colder polar maritime incursions over the next few weeks some short-lived snowy surprises could occur at times especially in the North.
The Jet Stream remains very strong exiting the States and crossing the Atlantic on a collision course for the UK for this week and probably next too with little sign of any major shift of axis and strength to get us out of this very volatile weather pattern.
In Summary it's more of the same today with plenty of wind and rain the talking points of the weather over the 2 week period. There is some output that worryingly suggests a powerful storm system near the UK over Christmas itself with the potential for disruption from strong winds and heavy rain over the period should it evolve as shown. However, rain and gales look like occurring with frequency throughout the period and it will be cold enough at times for some wintry showers as the storm systems recede away each time, only to quickly be replaced by milder and wet weather once more. GFS does show a more NW feed at the end of it's run prolonging a colder and more showery phase at the end of it's output but this is a long way out and to be honest there is little evidence of any pattern shift to what we have now when looking at those charts that go out to 10-14 days from now.
Martin G
Kilmersdon Radstock Bath Somerset