Hi everyone and good morning. Here is my no frills text account of the midnight outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Saturday November 30th 2013.
All models continue to show High pressure in control of the UK weather for the next 3-4 days with a fine day today with plenty of sunshine but overall cloudy conditions developing from tonight with benign and quiet conditions lasting thereon until the middle of next week with temperatures close to average.
The GFS operational then shows winds increasing across the North on Wednesday and further South on Thursday. A band of rain will be moving South across the UK on Wednesday followed by another on Thursday/Friday with clearer and colder conditions reaching the North briefly with wintry showers in places. This dry and cold weather may reach the South too very briefly before it is swept away NE by Low pressure along with milder, wet and windier weather later next weekend. This then sets up a much more mobile pattern with details irrelevant at this range but the general theme would be wet and windy weather alternating with brief colder interludes with wintry showers across the North at times. Overall temperatures would return to average but maybe returning rather colder later.
UKMO this morning ends next week with cold weather plunging South on Friday with rain in the South clearing to showers of sleet and snow, albeit briefly and mostly across the North and coastal areas in the East and West next weekend with frosts at night and a cold and strong Northerly wind.
GEM today shows no more than a glancing blow from the cold weather next weekend across principally Northern and Eastern areas where wintry showers may occur for a time with frost at night. Further South and West changes will be very tempered and in any event the trend from the start of the new week is for all areas to become mild and rather cloudy with Southerly winds from the Canaries to embalm the UK in mild air as we move into next week, perhaps with some rain in the North and West.
NAVGEM shows a brief encounter with colder air next weekend preceded by some rain and a fresh West wind as a depression moves steadily East across the North. A day of wintry showers look possible before a brief ridge crosses East drying things up perhaps with a night frost or two next weekend with temperatures below average at that time.
ECM today shows the most coherent cold snap next weekend with a two to three day window from next Friday of cold NW then North winds with snow showers, appreciable over Northern hills likely for a period. A ridge of High pressure moving steadily SE to our SW does show the flow being moderated by milder air rounding the High and down across the UK on a NW flow by the start of the new week with rather cloudy and benign conditions returning for many away from the far East where it may well still feel cold and breezy at times perhaps with a few showers, mostly of rain by then.
The GFS Ensembles show that (leaving the operational run to one side as it looks very suspect this morning) the weather looks like staying generally close to average temperature wise as we move through the run. The cold snap though still present for the North and East makes little inroads over the South before SW winds and more changeable weather looks the favoured consensus between the members through the second half of the run. As mentioned with SW winds predominating later in the run and with High pressure likely to be to the SE it will be mild for many especially to the East of high ground with most of the rain towards the North and West.
The Jet Stream currently travelling East at high latitudes well to the North of the UK slowly sinks further South as we go through next week as High pressure tries to give way somewhat. However, after a brief lull a surge of strong jet energy is then sent across the Atlantic and across the British Isles later in the run pumping up the potential for some deep Atlantic depressions to our NW later in the run, borne out by some of GFS's output this morning.
In Summary there is still a period of quiet anticyclonic weather for most areas between now and Wednesday. However, all eyes are on events thereafter with potential for a cold plunge of air to occur over Britain next weekend albeit rather brief. The American models seem to want less to do with this and allows the South to escpae almost entirely while the North sees something of a glancing blow at colder weather for a time. The Euro models are more productive though with ECM leading the field in producing a 2-3 day window of very cold and wintry weather with snow showers and very sharp night frosts. Nevertheless, it looks nothing more than a brief affair with the Jet Stream shown to power up to our West later throwing the potential for the Atlantic to create some large depressions out to the NW with all areas looking favoured to come under their influence with spells of rain and showers along with occasional gales. Though technically mild towards the end of the period some colder injections could affect the North at times with wintry showers over the hills.
Martin G
Kilmersdon Radstock Bath Somerset