Good evening everyone. Here is the report of the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Monday Deceember 9th 2013.
All models continue the theme of dry and fine weather for the remainder of this week as High pressure is maintained to the SE and Low over the Atlantic. However, NW Britain will be the exception to this with cloudy skies from troughs just to the West with outbreaks of rain at times along with strong winds. It will be mild here. Further South and East it will be brighter with some pleasant sunshine in between cloudier spells and by night clearer skies could give rise to patchy frost and fog in places, slow to clear by day. By the weekend things may begin to turn somewhat more unsettled for rather more of the UK with the East alone staying dry. However, it's here where the models diverge a little in how this transpires.
GFS then sets up a very mobile pattern for the second half of the run with rain at times for all. With winds permanently from a positions between South and NW the temperatures will remain quite respectable for December with little chance of significant frost, fog, sleet or snow.
UKMO closes it's run for next Sunday with a very deep Low near Iceland with a stronger and strengthening SW flow with most areas having become more changeable with some rain at times, especially in the North and West. Temperatures would remain near to or a little above average for most.
GEM tonight brings a change too next weekend with some rain ahead of a decline into potentially quite stormy conditions as intense depressions cross quickly NE over or just to the NW with very wet and windy conditions developing fr all, especially but not exclusively to the North and West. Temperatures would remain close to average but it would feel chilly in the wind and rain next week.
NAVGEM also shows a period of more unsettled weather at least for a time with some rain likely for all as winds freshen markedly from the West in response to low pressure crossing East to the north of Scotland. Temperatures look like being close to average overall.
ECM tonight shows a much more Wintry looking set of charts for next week as High pressure influence to the SE is lost in preference to deep Low pressure covering the North Atlantic. Very unstable WSW winds would bring spells of rain and showers, some heavy later with thunder and hail as somewhat colder conditions take hold with temperatures close to average at best. Winds would be starong at times too with gales in the North and West.
The GFS Ensembles show a steady decline towards more average December levels from later this week with rain developing at times in all areas with time though amounts in the South will be largely suppressed.
The Jet Stream tonight's most notable attribute is the strength of it's flow as it powers NE to the NW of Britain through this week. It then shows a continued trend to bring the axis further SE to run NE over the UK next week hence the incursion of more mobile Atlantic weather type with rain and showers and storm systems to the NW of the UK.
In Summary tonight there is definitive trend that things may begin to change from the weekend. While we are unlikely to move towards anything wintry in the way of snow and ice we will probably get out of the rut of dry and mild weather as many of us will see this week into something more interesting with wind and rain becoming much more widespread through next week along with some strong West or SW winds at times. Some models do show the effects to the South as still quite limited while others suggest the South will also share in some heavy rain and gales at times. It will be interesting to see how this growing trend develops or subsides again over the coming model runs.
Martin G
Kilmersdon Radstock Bath Somerset