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 SUNDAY MAY 8TH 2016
THE CURRENT GENERAL SITUATION Low pressure over Spain and later France will push troughs up across Southern Britain over the coming days in a warm and moist Easterly flow. The North will be largely set fair in the same Easterly flow though here the air will be more stable than in areas further South.
http://www.wetterzentrale.de/pics/Rtavn001.gif
CURRENT SNOW FORECAST AND/OR FREEZING LEVEL OVER THE UK The UK continues to see the freezing level across the UK range between 8000-10000ft over the following three or four days and these levels will extend to the far NW too today where values have been rather lower than elsewhere across the UK recently.
http://www.snow-forecast.com/maps/dynamic/uk
http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif
MODELS-2 WEEK HEADLINE Rather warm with thundery showers in the South. Perhaps rather cooler later.
THE GFS JET STREAM FORECAST The Jet Stream's main core is situated well South of the UK near Southern Spain and North Africa in association with a large depression down there. This remains for much of this before a rise in pressure over the Eastern Atlantic pushes a thread of the flow South across the UK in a Northerly flow. Then late in the period a rather complex Jet stream pattern emerges with the main energy still wanting to lie to the South of the UK rather than elsewhere.
http://www.netweather.tv/index.cgi?action=jetstream
GFS OPERATIONAL The GFS Operational Run today shows Low pressure down to the South and later to the SE of the UK this week with Easterly winds and showery weather for many Southern areas with rather warm and in places humid conditions prevailing. In the North it will stay largely dry and this will extend to Western areas further South towards next weekend as the Low to the South moves East and winds back to a cooler Northerly though with further heavy showers across Southern and later Eastern areas of the UK. Then through the second week details look elusive but in essence the UK looks to remain close to showery Low pressure with some bright and sunny intervals in between but with temperatures more likely to have returned to normal values by then at the same time as being less humid as winds back more to a Westerly at times.
http://www.wetterzentrale.de/pics/Rtavn1441.gif
http://www.wetterzentrale.de/pics/Rtavn3841.gif
NEW GFS PARALLEL RUN Using the GFS Operational Run above as a template for the coming two weeks the GFS Parallel Run today differs in that higher pressure is shown to extend East into the UK next weekend with a fine and bright spell lasting for several days and perhaps longer across the South before a return to unsettled and possibly windy conditions spreads down across all areas later, this time from the NW with temperatures after a warm start reverting to nearer to average values.
http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=0&runpara=1
http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=384&mode=0&runpara=1
GFS CONTROL RUN This run follows closer to the Operational rather than the Parallel Run through the phase surrounding next weekend and the start of the second week with continues showery conditions in winds from a cooler Northerly source. However, late in the period this run shows warm and sunny conditions developing across England and Wales as the Azores High extends NE into Southern Britain with any wind and rain held across the far NW.
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 clustering today for day 14 remains distinctly useless as a tool into what conditions will be like over the UK in two weeks time with an equal split of both Low and High pressure scenarios on offer meaning everything from potentially dry and sunny weather to cool and showery conditions in a Northerly flow.
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 the thundery Low pressure area currently over Spain dominant across Southern and later Eastern areas of the UK throughout this coming week as it slowly trundles it's way East to lie over SE Europe by next weekend with contrasting High pressure centred up to the NW of the British Isles by then resulting in a fall off in temperatures under the Northerly or NE'ly aspect to the flow by then with many North-western areas of the UK having an entirely dry and warm week while the South and East see further heavy showers at times right out to and probably including next weekend.
http://www.wetterzentrale.de/pics/Rukm1441.gif
THE FAX CHARTS The Fax Charts show quite a complex scenario revolving around the movement of Low pressure over Spain and it's effects on the UK. The basic message is for the NW to see the best conditions with fronts moving into the South at times with some heavy and thundery rain in humid conditions until later in the week when an attack of fronts from the North looks like reducing temperatures to average with the risk of further showers at times in winds becoming more from the North by next weekend lowering the humidity values.
http://www.weathercharts.org/ukmomslp.htm#t120
GEM GEM this morning shows slow but subtle changes in it's patterning over the next week to 10 days as the current warm and humid SE flow backs away towards the NE and later North with the showery conditions across the South and East too later this week breaking down under High pressure inching in from the West by next weekend with fine and less warm conditions for all for several days before High pressure to the WSW sets up a WNW flow across the UK with rather more unsettled conditions affecting the North and NE late in the run with the SW seeing the driest and warmest conditions by then.
http://www.wetterzentrale.de/pics/Rgem2401.gif
NAVGEM NAVGEM today also shows the slow decline in conditions from the South affecting the UK as winds back more towards the NE and North through the coming week. However, thundery showers will affect many Southern and Eastern areas for a good few days yet and it will feel warm in any sunshine. Then by next weekend a cooler North flow and showers transferring towards the East will spell a slow change to a more Atlantic based west or NW pattern by the start of the second week.
http://www.wetterzentrale.de/pics/Rnvg1681.gif
ECM ECM today also shows High pressure inching in from the West next weekend and into the second week but it never quite makes it maintaining something of a Northerly drift down across the UK with perhaps a few showers still in the East and more importantly cleaning up the air into a cooler fresher feel. As we approach the end of the run it shows more instability being injected into the air across the UK with showers returning to all this time from the NW.
http://www.wetterzentrale.de/pics/Recm2401.gif
ECM 10 DAY MEAN (12z) Last nights 10 day Mean Chart has backed a ridge West from earlier versions of this chart which leads me to believe that any advancement of High pressure into the UK from the West from next weekend will be slow, painstaking or at worst non-existent...more runs needed.
http://www.wetterzentrale.de/pics/Reem2401.gif
NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The theme remains for a warm and humid period of weather across the UK before a gradual reduction in both temperatures and showers look likely later though conditions beyond next weekend still come with low confidence.
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 99.4 pts and GFS at 99.2 pts. At 3 days ECM is leading with 97.1 pts to UKMO's 96.2 pts while GFS lags behind at 95.5 pts. At 5 days ECM leads with 88.3 pts to UKMO at 86.5pts and GFS at 83.2 pts. Then at 8 Days ECM has the leading spot from GFS with 61.2 pts to 51.3 pts. Finally at Day 10 ECM has the lead from GFS with a score of 44.5 pts to 36.2 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 Although the overall patterning of the weather over the next week looks pretty much set in stone the method and in particular local detail that gets us out of this pattern for the period surrounding next weekend and beyond remains very uncertain. So step by step what we have now is Low pressure down over Spain and Portugal which incidentally is giving some pretty inclement May weather down there and some of this is heading up towards Southern Britain to affect these areas between tomorrow and Wednesday. The warm and humid feed of air surrounding this will affect much of the UK but the North looks like getting away with a largely dry spell over the coming 3-4 days with the highest temperatures to the NW. Then as the week progresses the trend will be for winds to back away from the SE to more of a NEy feed by the end of the working week lowering both temperature and humidity values somewhat while maintaining some showery weather to include eastern areas too by that time. It's from then that the confusion between the models start as colder air will be moving South across Scandinavia and with High pressure to the West and NW of the UK this could be driven our way with the models in total disarray about how much of that cold and showery air will affect conditions over the UK. Some output suggests not much while others maintain a cooler Northerly drift with further showers eventually culminating in further unsettled weather fed down from the NW with rain and showers at times to end the forecast period. However, this is not the only option with other output suggesting High pressure ridging towards the South and setting up more of a NW/SE split at least for a time with the SE half of the UK becoming warm and dry with rain and wind towards the NW. It will be interesting to see how the models handle the changes through the coming week as all options shown look to me totally feasible. However, to end with the more definitive part of the forecast it looks a showery week to come especially across the South and East where they could be heavy and thundery at times. The best weather looks to be towards the NW this week and after a very warm start for some the conditions look set to turn rather cooler by next weekend with temperatures closer to the seasonal average at the same time as feeling less humid.
Next Update Monday May 9th 2016 from 09:00
Edited by user
08 May 2016 07:56:27
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Reason: Not specified
Martin G
Kilmersdon Radstock Bath Somerset