Good evening. Here is the Christmas Eve report on today's NWP midday output.
All models show an intense Low close to NW Scotland moving slowly North and filling slowly. A rather cold SW flow covers the UK with most showers over the Christmas period hugging coastal areas facing South and West and it maybe that many inland areas stay largely dry and bright with some sunshine by day with a touch of frost by night. Where showers do occur they could be heavy and wintry over any high ground above 250 mtrs. By the end of Boxing Day a new storm is shown to move in off the Atlantic with further very strong winds and heavy rain commencing 48 hrs from now in the SW and spreading quickly NE to all areas overnight. On Friday the rain will clear East to sunshine and showers in a strong WSW wind again and snow will fall from these showers too over the hills in the North. This showery theme then continues over next weekend with the showers dying away on Sunday as a weak ridge is shown to cross from the West.
GFS then shows another storm system to take us up to the New Year with yet another Low pressure coming into the UK from the West. This then fills in situ over the days up to the New Year and into 2014 itself with showers or outbreaks of rain, falling as snow over the hills in decreasing winds over the period. Low pressure then pulls down from the NW and settles towards the SE of Britain by the end of the run with a change to much colder and unsettled weather with sleet and snow becoming much more prominent should it verify in a cold and blustery NE flow with High pressure having built North through mid Atlantic.
UKMO tonight shows next Monday with a new Low pressure in the Central North Atlantic with a WSW flow over the UK. Troughs in the flow will continue to bring rain at times and it will fall as snow for a time over Northern hills. In the South it looks somewhat milder later.
GEM shows a continuing flow of Low pressure moving West to East across Britain from a weeks time though with less explosive force as recently. There would be spells of rain and showers for all but it should be less windy than recently.
NAVGEM closes it's run with Low pressure still well in control with centres close to or over the UK with plenty of wind and rain for many areas under temperatures close to average.
ECM keeps the unsettled and changeable theme going later in it's run though the charts look far less stormy than recently. Nevertheless there will be troughs crossing East in the Westerly flow with rain or showers at times in temperatures never far from average though it may turn rather cold towards the end of the run in a more NW flow.
The GFS Ensembles show that the weather remains changeable for the next 10 days. There is some support between it's own members of a cool off at the end of the run when it would become rather less wet though the operational is at the extreme end of this scenario.
The Jet Stream shows the flow remaining close to or just to the South of the UK tonight keeping the UK under a trough throughout the run meaning Low pressure close by. Evidence of a build of pressure in the Atlantic is shown towards the end of Week 2.
In Summary tonight the weather stays on an unsettled track for a good while to come. After a relatively quiet and showery Christmas another powerful storm looks likely later this week and the weekend before less stormy conditions are trended thereafter. Nevertheless there seems little evidence of any settled conditions with further rain expected off and on throughout the next few weeks with the saturated ground having little chance to recover. GFS does show some signs of a pattern change late in it's outputs supported by some of it's own ensemble members. However, I feel that we need such a trend developed on over the coming days and given more cross model support once such a change comes within all models time range.
A Very Merry Christmas to you all.
Martin G
Kilmersdon Radstock Bath Somerset