So what happened to the hot weather we going to get this weekend? If this LP over France allow them seeing high temps and dry while us on Sunday with a ridge of HP get low temps instead of high 20's low 30's as shown recently.

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON THURSDAY AUG 27TH 2015

THE CURRENT GENERAL SITUATION A trough of Low pressure will lie across Northern France today, clearing away to the SE tonight. A showery WSW flow will continue to affect all parts of the UK.

http://www.wetterzentrale.de/pics/Rtavn001.gif

MODELS-2 WEEK HEADLINE Gradually becoming less unsettled with longer dry spells and some sunny spells next week.

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast pattern shown this morning indicates a slow shift of the SW to NE  moving flow across the UK currently to move towards Europe while over and around the UK the flow becomes weak and ill defined for some considerable time from next week onward. Late in the run the flow realigns to a point well South of the UK allowing pressure to fall over and around the UK.

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS Operational Run today shows rather changeable conditions over this weekend with some showers and rain around in slack synoptics. Then through next week and the rest of the run High pressure takes control over the UK. The High cell is shown to edge in only slowly giving several days of cool Northerly winds and jolly chilly nights but bright, sunny days. Then later in the period temperatures rise as the Northerly flow is cut off by the High cell settling over the UK. Very late in the period the High migrates to the NE allowing pressure to fall across the UK with some rain or showers returning to the South and SW in particular.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif

THE GFS CONTROL The GFS Control Run today is in many ways very similar in theme to it's operational companion this morning indicating a strong influence from High pressure affecting the UK through the period. Things start slowly as the cool North or NE flow for a while tempers any warmth and gives rise to some very cool nights and the odd shower in the East. Then through Week 2 the High settles across the UK with a warming trend in light winds with days of warm sunshine coupled with cool and perhaps increasingly misty nights.

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show a bias of approximately 65%/35% in favour of High pressure across or near the UK in 14 days time. 35% of the members show High pressure over the UK while another 30% show High pressure affecting the South most while the other 35% indicate varying degrees of influence from Atlantic Low pressure to the North or NW.

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 UKMO today shows the changeable Bank Holiday Weekend under shallow Low pressure  giving way to a large mid Atlantic High developing next week and on this run it keeps it well West of the UK out to next Wednesday maintaining the developed Northerly flow across the UK ensuring temperatures stay somewhat suppressed but being compensated by some dry and fine weather with just a few daytime showers towards the East and jolly chilly nights under any clear skies.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts this morning show a lot of slack pressure patterns over the UK come the weekend with a stubborn trough slow moving near the South on Sunday with rain at times here while the North and West see sunshine and showers in a SW breeze. Things remain rather showery looking on Bank Holiday Monday under Low pressure to the NW and an exiting Low to the East.

http://www.weathercharts.org/ukmomslp.htm#t120.

GEM GEM today also show slow improvements next week with slow being the buzz word. High pressure in the Atlantic with Low pressure over Northern Europe show Northerly winds and showers for quite a portion of next week slowly giving way to dry and fine weather next weekend as the High pressure to the West finally comes to rest across the UK.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM also shows a similar theme to the rest with the painfully slow ingress of High pressure from the West tempering the cool Northerly flow down across the UK for the early and mid week days with the High pressure still lying West of Ireland next Thursday.

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

ECM ECM this morning is still showing strong indications of a pattern change next week with High pressure gradually becoming more influential across the UK, this felt most by those in the Summer long afflicted NW where dry and fine weather will predominate from early next week with dry, bright days and jolly cold nights. Improvements will be felt elsewhere too with the cool North or NE flow and the odd shower in the East during the week falling light by next weekend.

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening continues to endorse the prospect that the UK could lie close to or under High pressure in 10 days time

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models have strengthened their theme towards High pressure based weather developing next week from off the Atlantic.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 96.2 pts followed by UKMO at 96.0 pts and GFS at 94.9 pts. At 5 days UKMO is king at 87.1 pts followed by ECM at 86.3 and GFS at 83.3 pts. Then at 8 Days ECM still leads at 61.2 pts over GFS's 55.2 pts. Finally at Day 10 ECM leads GFS at 43.9 pts to 38.0 pts from GFS.
 
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.prig
 
MY THOUGHTS At last this morning I can report on the strong possibility of a pattern change in the weather across the UK most welcome of all for those living in the NW. We still have several more days to go on the current rather changeable theme of weather and although the Holiday Weekend looks far from a write off temperatures could be a bit better and the patchy rain and shower risk for most areas is an unwanted ingredient of the weekend forecast. Nevertheless, it could be worse as the  threat of UK wide wind and rain moving up from the SW on Sunday has receded somewhat so to affect more Southern areas only for a time. We then finally see pressure building out over the Atlantic next week at much higher latitudes than of late spawning some better weather for the UK. The down side of this in the short term is the persistence of a Northerly flow down across the UK for much of next week as Low pressure by then out over Northern Europe holds up the migration East of the Atlantic High into the UK. The resultant weather looks set fair next week for many with some sunshine by day with odd showers still flirting with Eastern areas in particular at times, also a chilly North wind will likely be blowing holding temperatures back at average levels but probably most notable of all will be some very cold nights for early September with frost a real possibility for many, certainly in the North and frost hollows elsewhere too. Then looking further ahead the High pressure should make landfall across Britain by next weekend which would cut off any cold Northerly feed with light and warming winds then especially by day but with the risk of mists and fogs by night. Any suggestion of a breakdown following this stage is at this range futile so I will not mention any methology on how this might occur on output shown today.

It really is nice to report on something positive for the UK in terms of better weather for all of the UK as a whole and not just the SE and I'm sure the NW will salivate over the real prospect of a sustained dry spell commencing next week after recent months monotony. While improvements in the SE will be less notable under the Northerly flow expected next week it's nice to see High pressure largely dictating the weather events here too rather than Low pressure up to the NW or SW. Lets hope I haven't given my predictions the kiss of death in my positivity this morning but I do feel for once that with such a lot of cross model support for High pressure to become dominant from the West next week we can say with reasonable confidence that a marked improvement is on the way even if it's not on this occasion in the shape of a late season heatwave.

Next update from 09:00 Friday Aug 28th 2015

Looks like next week the first week of Autumn is starting off on a cool if not very cool note with N/NW winds for much of next week with temps into the low to mid teens.

At least it will be (mostly) dry, if the models have it right.

Should do as a big HP on the west side is my favourite set-up as it keep all LP out of reach from hitting UK and by September under northerly flow would bring very clear skies and temps around 20 to low 20's as the sun still strong enough while nights get cooler.

GFS shows the pattern changing again after about a week under the cool northerly flow:

This happens to be the type of setup that a strong East-Pacific (rather than central) El Nino promotes during the winter months. It would be quite something to see it in September - mid to high 20's widely with a chance of 30*C in the south. Slow to break down as well!

ECM doesn't look to keen on following such a route from its day 10 chart it has to be said, with the high over the UK actually looking to become a cut-off feature as Atlantic LP gains a negative tilt (leading edge aligned SE to NW rather than SW to NE) with hints of trough disruption (where LP develops a secondary disturbance on the leading edge which then breaks away and potentially becomes a cut-off low, separated from the usual westerly progression of systems):

GFS gets where it does by having a strong area of LP develop in the Atlantic, tilting the jet back to the usual SW-NE orientation. It then 'flattens' the UK high, but after toppling into Europe it gains broad-scale support as the polar jet digs south well west of the UK and meets with the subtropical jet. That second jet stream tends to become more vigorous during El Nino events, and is one of the reasons why Euro Highs tend to become stronger and more persistent... but as I said earlier, this response usually occurs in winter, rather than autumn.

This particular El Nino really flew out of the starting blocks in March, a month or two earlier than most events get underway, so perhaps that means an earlier awakening of the subtropical jet. For it to be earlier by four months seems way to soon, but hey - every El Nino has its own unique characteristics so there's room for all sorts of variation I expect!

Most likely GFS drops this on the 18z and it doesn't come back again for quite some time, but you know what, I'd really like this to be a case of GFS picking up on the establishment of an unusual setup well in advance, because hot days in September are a real novelty, what with the sun getting lower in the sky and packing less of a punch.

Hot days in September are excellent - It would be well appreciated especially after a poor August which this has now turned out to be.

http://www.meteociel.fr/modeles/ecmwf/runs/2015082712/ECM1-240.GIF?27-0 

If only it was winter  nice settled and warm for the start of autumn though.

http://www.wetterzentrale.de/pics/Rhgfs664.gif

That the story of poor 2015 summer continue with real heat all over the continent and UK left out.  I think the continent will be hit hard by September with lot of unsettled weather while UK becoming the best place for HP long term settlement.  

Ensembles painting as dry a picture as I've seen for a long time (after the weekend low).

The west especially looks to have some good weather coming up   

Classic September harvesting weather for spring sown cereals. 

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON FRIDAY AUG 28TH 2015

THE CURRENT GENERAL SITUATION. A showery SW flow will blow across the UK today and tomorrow within the influence of Low pressure to the NW of the UK.

http://www.wetterzentrale.de/pics/Rtavn001.gif

MODELS-2 WEEK HEADLINE Becoming drier and brighter for many especially towards the NW. A cool breeze at times with a few showers in the SE with some very cool and misty nights for many.

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast pattern shown this morning indicates the flow running NE across the South of Britain for a few more days before the flow weakens and migrates away East leaving the flow disjointed and weak with the main core well North of the UK next week. The flow then rejuvenates late in the period, location uncertain but probably to the South of the UK again.

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS Operational Run today shows High pressure developing to the West of the UK after the weekend and maintaining influence throughout the rest of the period. The changeable pattern of late will continue for a few more days as the Low to the NW and a disturbance running NE over the South on Sunday moves away NE on Monday and sets up a cool Northerly for several days next week. The developed High to the West is then shown to drift slowly ENE into Scotland later next week and through Week 2 with a cool NE flow for much of the time over the South with a few showers while the North and West see the best of the weather with long sunny spells and dry weather but with cool and misty early Autumn nights for many.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif

THE GFS CONTROL The GFS Control Run today also shows High pressure developing West of Ireland from the end of the weekend and remaining influential to the UK from then until the end of the period. The position to the west of Ireland also means a cool North and then NE flow is likely across the UK next week before the High shifts slowly East across Scotland and into Europe cutting off the cool flow over the South and meaning light winds for all and a continuation of largely fine and dry conditions as a ridge still lies West across the UK from it at the end of the period

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show an overwhelming odds in favour of fine weather likely to lie across at least the South of the UK in two weeks time as a High pressure ridge is likely to lie close to the South in 14 days time. There are some members who show more unsettled weather especially for the North and a fewer still who show Low pressure close to the South with rain at times.

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 UKMO today shows the changeable Bank Holiday Weekend under shallow Low pressure  giving way to High pressure, building over the Atlantic early next week and drifting close to NW Scotland by midweek delivering a lot of fine and rather cool weather especially by night. Daytime showers are possible towards the East and SE in the cool NE breeze.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts this morning show the complex trough structure to the South of the UK in the coming days nudging up into Southern Britain for a time before drifting away East as the chilly North flow develops next week in association with High pressure to the West.

http://www.weathercharts.org/ukmomslp.htm#t120.

GEM GEM today also shows High pressure building slowly from the West next week with the chilly North flow through much of the week gradually being replaced by light and variable winds as the High moves across the UK by next weekend. A lot of dry weather would prevail with just odd showers drifting down in the flow next week before all areas become dry and less cool by next weekend.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM follows the same path as the rest of the models in bringing High pressure into the mix positioning it to the West of the UK early next week with a cool North flow over the UK. this veers towards the NE late next week as the High inches in closer to the NW of Britain. Apart from a few showers through the week confining themselves to the East and SE later a lot of dry and fine weather is expected, best in the NW.

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

ECM ECM this morning completes the set in showing High pressure becoming influential across the UK from early next week. It too shows the High settling to the West of the UK, moving in closer towards NW Britain at the end of next week before weakening and slipping to the East by Day 10 as pressure falls to the West. All this means a lot of fine, dry of somewhat cool temperatures especially by night. A few showers are possible in the SE for a while before all areas become fine, benign and less cool late in the period as the NE feed is cut off.

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last evening continues to endorse the prospect that the UK could lie under High pressure in 10 days time.

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models continue their theme towards High pressure based weather developing next week from off the Atlantic.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM. This morning's verification statistics show ECM leading the way at 3 days with 96.2 pts followed by UKMO at 96.0 pts and GFS at 95.0 pts. At 5 days UKMO is king at 87.3 pts followed by ECM at 86.7 and GFS at 83.8 pts. Then at 8 Days ECM still leads at 61.7 pts over GFS's 54.1 pts. Finally at Day 10 ECM leads GFS at 43.1 pts to 37.6 pts from GFS.
 
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.prig
 
MY THOUGHTS The models continue their theme of much more High pressure based weather likely to affect the UK next week and probably well beyond. This may come a little to late to benefit the Bank Holiday Weekend which still looks a little changeable with some rain in places especially on Sunday. Then it looks like a Northerly flow will develop across all areas next week, preventing warm conditions but delivering a lot of fine and sunny weather but with the risk of some showers too in the East and SE. As I indicated yesterday the biggest benefits of this pattern change will affect the NW most where after Monday mostly dry conditions will prevail thereon with some fine sunny days but with some jolly chilly nights with grass frosts and mist and fog patches possible. As we move towards next weekend many models drift the High into the NW or North of the UK with still something of a nagging and cool NE breeze across the South with isolated showers. Then looking further ahead still the models maintain a HIgh pressure based pattern with the centre then having probably migrated to the east or NE of the UK which both ECM and GFS show with perhaps the first inclination towards change shown after Day 10 as pressure falls to the West. All this of course is a long way off and there will of been a lot of fine and dry weather to have been enjoyed before we reach that point. So all in all a fine spell to come and while there are unlikely to be any record breaking high temperatures to report on there could be some jolly chilly nights for this stage of Autumn with some early grass frosts and the introduction of mist and fog patches too for some. Nevertheless it is nice to report on some nice weather for many and to take a break from chasing areas of cloud and rain around to which we have become so accustomed of late.

Next update from 09:00 Saturday Aug 29th 2015

Thank you Martin for the fine weather output.. Not liking the idea of frosts...  Must look for my bubble wrap ...

Your model analysis is always my first read of the day Martin. Thanks for doing this. A rare post from me these days but I just wanted to say that I am not convinced we are going to get large amounts of sunshine from this high pressure system. Large high pressure systems moving in off the Atlantic always seem to draw large cloud amounts with them. In addition, cool air will be pulled south over the UK which generally encourages cloud development as the day progresses. Finally, I'm expecting cloud off the North Sea as an east/north easterly flow develops.
I'm not saying we're in for a cloud fest but I think favoured locations for sunshine will vary over the course of time. I also think that we'll get the usual UK pattern of cloud clearing overnight too. Hopefully I'll be proved wrong!

Lo and behold - 3 days later and that's how things are now starting to manifest in the model output 

Luck. Pure luck. I haven't got any time for these trumpet-blowing LRF'ers.

Thanks for the support and though I don't get time to post much during the days I always read this model forum page each evening as a nightcap. With regard to the cloud amounts you could be right of course but I'm hoping the High stays far enough to the NW to prevent any infill of cloud moving around it's Northern flank and down over the UK. At the moment it looks like the air from it is going to be quite clean and cool so sunshine is highly probable though some infill of daytime cloud is inevitable and maybe a few showers towards the East and SE In respect of the ENE flow off the North sea later we are at the time of year when low cloud and haar is at it's least likely stage as sea temperatures are close to their maximum for the year at the moment which restricts the amount of it able to form and makes it easier to burn off in the still relatively warm land temperatures at this stage of the year.

Interesting to see the 06z GFS op, along with several of the high-res models (ARPEGE, WRF-NMM included), developing the Euro Low a fair bit further SW than previous runs.

That allows the hot, humid air to nudge in a little further than had been looking to be the case. Mid-20's are projected as far west as Bournemouth by the 06z GFS, though temps drop off quickly as you look north.

This brings with it the threat of some very heavy rain developing overnight into Monday, perhaps with some thunderstorms for a time although CAPE doesn't look all that high. With hourly precipitable water amounts potentially reaching as high as 50mm, there could be some very intense rain rates if it all comes together in the right (i.e. wrong for the sodden south*!) way.

Longer term, ECM's suddenly got on the progressive bandwagon, as a burst of N. Atlantic westerlies shoves the large area of high pressure over to Scandinavia by day 9. Things look at risk of destabilising going forward, as the Atlantic jet muscles into the region just SW of the UK. Perhaps there could be an attempt by low pressure to undercut the high?

Whatever the longer-term outcome would be, the 8-10 day evolution is quite a contrast to GFS' 00z op solution which had the high holding its own to our NNW for a number of days. Temperatures for the first half of the month produced an estimated CET more than 2*C below the LTA.

Thankfully, the 06z GFS has reverted to shoving the high east, and has also brought back the idea of the Atlantic troughs riding over the top of the high, the ridge then becoming entrenched over Europe. The mid-Atlantic jet remains too flat for the dramatic results seen in yesterday's 12z GFS op run, but the prevalence of largely dry, often warm conditions in the 10-16 day range will please many I'm sure.

I'm wary of the Atlantic jet really kicking into gear before too long though - I've been analysing zonal wind and SST data from previous years, and it's starting to look like the anomalous cold in the N. Atlantic this year could have the effect of promoting stronger than usual zonal winds at latitudes a little way south of the UK, with weaker than normal zonal winds to the NW of the UK. The jet stream is essentially a concentration of the zonal wind at high altitude (around 925hPa), so this zonal wind signal can be interpreted to mean that the jet stream will be inclined to get its act together and become strong unusually far south in the Atlantic. Meanwhile, high pressure may be more likely than usual to turn up NW of the UK.

I know it all sounds worryingly like a variant of what we saw in winter 2013/14, but that pattern was driven more by anomalously high Indonesian rainfall, so hopefully we're not looking at something so persistent this autumn.

Assuming, of course, that what I'm seeing in past years is significant. Analysis of further years (I'm only a dozen in) will hopefully clarify matters.

* I use this term metaphorically - the ground surface here is actually remarkably dry now and the local streams have fallen back to almost as low as they were before the drenching began last Saturday. Behold the power of evapotranspiration!

September coming very soon and once it arrive the 2 weeks dry spell commence and temperatures next week should be warmer feel while lower uppers than this BH weekend despite faux uppers temps to 14C with raw mid teen maxes and rain all day.  Nights will be noticeable colder than late but it mean lot of wall to wall sunshine by day and last time to see all day sunshine back in May and April under the same set-up with large HP that block any unwanted LP from entering the UK for a long time.  Also it take a long time to move east so that give us 2 full week dry weather nationwide. much needed for the recent soggy south recently and the north after a long run of poor summer there. My 1 week off in mid September are appearing on the FI and show massive HP area but may this time keep this theme than recent summer runs that kept downgrading it.  I never take a holiday in August, never ever! Last time was in 1993 in Cyprus.