HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON MONDAY APR 18TH 2016
THE CURRENT GENERAL SITUATION A ridge of High pressure lies across the far South of England and will build further over the next 24 hours as well as extend further North tomorrow and Wednesday, killing off the weak trough currently moving South across Northern and Central areas
http://www.wetterzentrale.de/pics/Rtavn001.gif
CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will rise steadily through this week towards 6000-8000ft across the South later while the North will not be quite as high though comfortably above 3000ft in the North later
http://www.snow-forecast.com/maps/dynamic/uk
http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif
MODELS-2 WEEK HEADLINE A lot of dry and bright weather this week with cool nights then even chillier weather with sunshine and showers look likely with a continuing night frost risk thereafter.
THE GFS JET STREAM FORECAST The split flow in the Jet Stream will remain for a time through this week while later the flow simplifies by diving South across the UK and later still setting up a cyclonic flow around the UK.
http://www.netweather.tv/index.cgi?action=jetstream
GFS OPERATIONAL The GFS Operational Run today shows a lot of High pressure influenced weather this week as the centre drifts North from Southern England to lie across the UK through the working week. Then by and over the weekend to come it is pulled West and NW over the Atlantic opening the door to cold and showery weather to arrive from the North with some longer spells of rain too as Low pressure centres across the UK early next week filling only slowly in situ over the UK thereafter while maintaining rain and showers across the UK to end the period.
GFS CONTROL RUN The theme of the Control Run is pretty much the same as the High pressure zone this week is also pulled West and NW out into the Atlantic with cold and showery North winds followed by cyclonic winds all bringing a mix of rain and showers with perhaps some snow on hills especially at first in this phase. Towards the end of the run a brighter and drier period looks possible as Low pressure weakens but further unsettled weather looks poised to flood down from the NW at the final day of the run..
http://www.wetterzentrale.de/pics/Rtavn1441.gif
http://www.wetterzentrale.de/pics/Rtavn3841.gif
http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=144&mode=0&carte=0
http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=384&mode=0&carte=0
GFS ENSEMBLE DAY 14 DATA The GFS Clusters today once again appear to be a weak tool as there are few signals given this morning which give a clear guide as to where we might be meteorologically in two weeks time. Cyclonic conditions on the face of it seem more likely than not but infinite details about where pressure patterns will pan out in relation to the UK are unclear hence airflow patterns and sources make conditions at the surface hard to predict.
http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=
UKMO The UKMO model this morning shows High pressure well in control over much of this working week before it recedes to the West over the coming weekend with a chilly Northerly developing which brings the risk of showers, especially in the East but with plenty of dry weather still with some frost at night in the drier West and NW.
http://www.wetterzentrale.de/pics/Rukm1441.gif
THE FAX CHARTS The Fax Charts today agree with the theme of the Operational Run with High pressure through the week pushed out to the West by the weekend with a squeeze of troughs from both the South and North making the weather less reliably dry by the weekend as well as dropping temperatures downwards by the weekend as a North or NE wind takes hold.
http://www.weathercharts.org/ukmomslp.htm#t120
GEM GEM this morning also shows a largely dry and bright week to come before the same North winds develop by the weekend and accompanied by Low pressure moving in close to Eastern Britain rain and showers breaking out then too and under low temperatures some snow can be expected on the higher hills of the North. This pattern then largely remains locked into the midweek period next week with further rain or showers at times.
http://www.wetterzentrale.de/pics/Rgem2401.gif
NAVGEM NAVGEM too shows good support for a High pressure based week to come with fine days with some sunshine mixed with chilly nights with frost in places. It too by the weekend shows a slip into a colder Northerly wind though somewhat slacker than some other models but still capable of delivering showers as pressure falls across the UK and under any clear intervals overnight the light winds could give rise to night frosts.
http://www.wetterzentrale.de/pics/Rnvg1681.gif
ECM ECM today still maintains the theme of a relatively decent week of weather to come as High pressure across the UK slowly drifts West and NW by the weekend with a slow drift into a colder Northerly flow come the weekend with some showers breaking out in places. Then through the weekend and start of next week rather cold conditions with showers or rain at times looks more likely though on this run things might not turn quite as chilly as some of the previous versions of this model run has shown as the coldest temperatures become held further to the NW of the UK with more of an influence of Atlantic westerlies in the South though the overall weather pattern would become very unsettled for all.
http://www.wetterzentrale.de/pics/Recm2401.gif
ECM 10 DAY MEAN (12z) The 240hr mean Chart from last night shows n changes from the theme shown for days so the likelihood of a chilly North flow down across the UK is still a very likely one as we move towards the period 10 days hence.
http://www.wetterzentrale.de/pics/Reem2401.gif
NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS Changes are just small and subtle in the different ways in which a chilly Northerly flow is shown and as a result will likely be blowing down across the UK in the 10-14 day period.
31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with UKMO at 99.5 pts and GFS at 99.3 pts. At 3 days ECM is leading with 97.3 pts to UKMO's 96.7 pts while GFS lags behind at 95.6 pts. At 5 days ECM leads with 89.2 pts to UKMO at 86.9 pts and GFS at 83.6 pts. Then at 8 Days ECM has the leading spot from GFS with 65.7 pts to 58.9 pts. Finally at Day 10 ECM has the lead from GFS with a score of 44.9 pts to 39.9 pts.
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png
http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.png
MY THOUGHTS Still no major changes in the overall patterning between the models this morning. However, not all of the output is quite so strong in supporting really chilly air across the UK and ECM has thrown up a common scenario in this sort of setup where the coldest air stays to the NW of the UK as the Low pressure responsible moves across the UK from the NE and cuts off a direct Northerly feed that had previously been shown due to Low pressure holding out to the East. Nevertheless, this is just crumbs of comfort in an otherwise persistent pattern which nearly has a 100% of chance of verifying this morning. In the interim period High pressure lying across the UK will deliver some quite pleasant conditions this week with sunshine breaking out again by midweek after a couple of cloudy but largely dry days today and tomorrow. Then as winds freshen from the East later in the week there is still a decreasing threat of some rain moving up briefly from the South into the South though this looks a receding risk and it's not until winds back NE or North at the weekend when notable changes take hold. Colder air will plunge South again towards the weekend with an increasing risk of showers, first in the East and probably anywhere later and with air from such a cold source it will still be cold enough for some snow on Northern hills and mountains. The main concern for me is that once established there is little desire within the models to break us out of the pattern and as long as High pressure remains strong near Greenland it maybe that much of next week too remains cool and showery although there will be a fair amount of dry and bright weather too between the cold showers and it's at these times it will probably feel OK.
Next Update Tuesday April 19th 2016 from 09:00
Martin G
Kilmersdon Radstock Bath Somerset