Forecast for Bank Holiday Monday steadily deteriorating for the south with a developing low. A few days ago monday was dry with scattered showers. Somethings gone awry recently with forecasting. 

Yep the weather forecasts recently have been as much use as a chocolate teapot. No wonder the Met Office has lost it's contract with the BBC, though I doubt any other forecaster would manage any better tbh.

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 SATURDAY AUG 29TH 2015

THE CURRENT GENERAL SITUATION. A weak SW flow covers the UK today with slack pressure developing over the South as a warm front edges North into Southern Britain later tonight and tomorrow..

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 split weak and North and South of the UK. It then strengthens late in the period to blow West to east just to the North of Scotland later in Week 2.

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. Low pressure to the East and SE will aid the setup of a cool Northerly flow across the UK next week with jolly chilly nights and sunny spells by day with just a few showers towards the East and SE. The High pressure to the west is shown to edge closer day by day eventually cutting off the cool northerly feed and replacing it with clam conditions in the South. As a result it would become warmer by day and night but with some night fog patches possible. The end of the period sees the High slipping SE but maintaining fine weather across the South while the North becomes breezier under a Westerly flow with some Atlantic rain creeping in at times.

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 almost the end of the period. The positioning of the High in the second week is further to the North sitting across the UK for a time before slipping to the East late on and allowing a more general breakdown in conditions with rain at times to move in from the Atlantic by the end of the period.

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show a fairly even split on conditions in two weeks time with almost half still showing some High pressure influence across the South from a centre to the South, SE or SW while the threat of rain and Atlantic winds looks greater this morning for the North and NW in particular.

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 a cool week across the British Isles with the UK sandwiched between High pressure to the West of Scotland and Low pressure over Germany and the continent in general. A NNE flow across the UK should deliver a lot of fine and cool weather with jolly chilly nights but some showers are possible in the East and South at times.

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

THE FAX CHARTS The Fax Charts this morning show a complex and slow moving warm front across the South of the UK over the coming 72 hours, edging slowly NW then east by Tuesday of next week. Pulses of heavy and thundery rain within it's proximity look probable before the whole system moves away east and allows the setup of a cold northerly flow and with Low pressure quite close to the East for a time further showers are possible but with High pressure to the NW the West and NW in general will become dry if quite cool.

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

GEM GEM today shows High pressure developing to the West of the UK in the coming days but with Low pressure moving NE across the far SE over the coming days with some thundery rain at times in the South and East. Thereafter the High to the West is shown to agonizingly creep closer in to the west of the UK, never quite making it as a cool North or NE flow across Central and SE Britain is maintained.

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

NAVGEM NAVGEM follows a similar theme with High pressure inching in from the west towards Scotland later in the coming week with the frontal system in the SE to start clearing East fairly early in the period to leave a cool NNE flow for the remainder of the week for most parts.

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

ECM ECM this morning shows High pressure influence across the UK dominant throughout this morning's run with the positioning always I'm afraid too far West into the Atlantic to give the very best conditions across the UK. For the next few days we have to await the exit of a stubbornly slow moving frontal trough from the SE early next week then all areas fall under the influence of a cool Northerly feed with bright days and the odd shower in the East. Then as a ridge from the High slips South the weather will be dry for all and with time the cool North wind supply is cut off and rather cloudy Atlantic winds but dry weather looks like affecting the UK as they round the Northern flank of the High and move down over the UK in a NW flow.

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

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from this morning 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 95.9 pts and GFS at 95.0 pts. At 5 days UKMO is king at 87.1 pts followed by ECM at 86.6 and GFS at 83.7 pts. Then at 8 Days ECM still leads at 62.0 pts over GFS's 53.3 pts. Finally at Day 10 ECM leads GFS at 43.1 pts to 36.6 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 We have universal support from the models today that a pattern change is finally under way and the NW/SE split in the weather we have seen what seems endlessly of late is disappearing or being reversed for a time at least. Low pressure to the NW is finally being displaced by a rise of pressure over the Eastern Atlantic and while a thundery Low to the SE at first and Low pressure to the East later will not be beneficial to the UK improvements for the NW of the UK especially are going to be quite marked this week. On the negative side the positioning of the High is far from ideal from a UK perspective as it is too far West and aids a very chilly Northerly flow across the UK suppressing temperatures and allowing some daytime showers to affect the East and SE for some considerable while into next week. In the West and NW the best weather will be achieved with sunny days but with jolly chilly nights with rural frosts and mist patches. As we then look further forwards into the second week conditions may improve further with the Northerly flow probably cut off as the High migrates East across the UK delivering rather warmer uppers across the UK with warmer days and nights and still relatively dry conditions for all. In the far reaches of GFS today and hinted at within the clusters a greater chance of the Atlantic coming back into at least the North and West of the UK is shown but that is a long way off and all of the UK could at least see a period of almost totally dry conditions and while temperatures may not be nothing to write home about the farmers's harvest should be able to be completed within the first half of September without too much hindrance from the weather.

Next update from 09:00 Sunday Aug 30th 2015

It for the best since super computers was installed and more data forecasts had gone wronger than before.  Window watching is the only way to see now as I have no other reliable source to find out what the weather be like today and work out what it like tomorrow.  Models had been useless too even on now cast.

It's an unpredictable set up, and the forecasts can only say what the models are suggesting.

I just hope the current forecasts are spot on. We're in Caernarfon this weekend and it looks OK. Given we've had so many posters from the SE telling us how good this summer's been down there, perhaps it'd be fitting if the tables were turned for the last weekend of summer.

I'm from the southeast but I certainly wouldn't say the summer weather's been good, it's been the worst for years!!

Was planning to drive to Durdle Door on Monday and walk a small section of the Southwest Coastal path but will probably end up cooking a roast at mine for the family instead - again!!! 

It's been warmer and drier than average in the main - a typical recent SE summer, really. It's only in the last couple of weeks that we've had much in the way of rain down here! Heck, even in the Midlands the CET shows temperatures have been pretty much average. It's a case of people having too high an expectation, but that's for another thread...

It's interesting how the models have been struggling to pin down the details this weekend though. As it stands the forecast for Kent today is for humid, muggy but generally dry conditions: not the nicest weather to be out and about in but certainly useable. Just 48 hours ago today was looking like a wash-out! This follows hot on the heels of last weekend, where MetO/ECM were showing a high of 18C for Saturday as late as Wednesday, but it ended up in the high 20s instead!

Good post Darren! Locally, in Dover, a very decent summer

Meanwhile, today is a good example. Six days ago I posted that the next plume (today's one) would graze SE England in the fashion of summer 2015,

Topic: Model Output Discussion 20/8/15 17:10>>>   Posted: 25 August 2015 17:55:17

Sunday could end up being hot depending on the timing of the rain and the next plume.  Here is the 12z GFS with 15+ for the S and E.  Worth a watch to see if it continues and to see if it does, how the timing changes.

but as Stormchaser also noted, this was due to happen about now. (8am) with an attendant washout.  Six days later and the plume maxes out at 8pm this evening, half a day's difference and maxes of 25c are likely across Hampshire Sussex and Kent this afternoon in the sunshine that should develop.

Will this be the last plume of the summer half of the year?  I doubt it.

Here are the 850s for 2000hrs and the undercooked GFS maxes for 1700hrs (French time)

Kent people - Not worth the excitement of the damaged goods today and I am more keen on the proper nationwide HP spell starting from Tuesday with temperatures warmer feel at day time than this weekend poor show.  On ECM is show a proper easterly set-up and with already warmed up North Sea and much warmer Baltic we would get lovely warm air for a change with above average temps and lot of sunshine. Some much warmer air on FI which would be good for my mid week off in September.  I do hope September will deliver a proper heat plume with threshold of 28C that normally the hot levels max for September nearly every year on my records. not often reach 30C but if this happen it would be a bonus.

You're right, but I suspect the picture has been quite different to the southeast of London. I'm just up the road from you and this summer has been woeful but in Kent and Essex there has been more of a continental influence. I think the contrasting weather over a very short range is the main reason for why the computer models and forecasts have struggled at times.

Never has the SE/NW divide been so defined. Even here in SE England. For Kent it has been a continental summer. Today is a classic example of this as the overnight plumey channel storms rolled away earlier to bring a warm and sunny morning with temps pushing towards 70f already.

http://www.wetterzentrale.de/pics/Rhgfs424.gif

The horror of unfair summer 2015 with Europe baking hot since late June will finally come to the end once September come to kill this off which is a welcome relief for the UK that had suffered a very poor summer will able to get a proper HP spell.  Don't know why back in 1995, 2003, 2006 had the same extreme heat in Europe and we get the same party.  I never experience seeing UK 100% missing out the heat all the time when back in the past we get it very easily and last longer, not the few hours quickie damaged heat goods.

Using Eurostar meaning from cool and damp London to baking hot Paris for those that used it this summer.  I went to Paris back in mid June and that time it was both the same weather ableit normal 2C warmer there before the onslaught of the heat took place and UK left out completely since then.

I am sure the Europeans viewing their models would be very happy to see the heat gone as it been there for 2 solid months.

The ECM 00z run looks decent for more western (especially northwestern) parts but less so across the SE.

http://www.wetterzentrale.de/pics/Recm2161.gif

Personally I would not appreciate an easterly here with SSTs to the immediate east at 12 to 13°C.

FWIW the BBC forecast had just said that parts of the far S/SE may reach 22 or 23°C today - that's not that far off the GFS maxima?

It also decent from my records with sunny, fresher drier easterly winds that I saw many times in Spring time but this time with warmer temps as the sea already at the warm peak.  You shouldn't get strong easterly than here with stronger HP over the NW.  That the first time I see NW get strong HP cell since Spring.

Those temps 22-23C are nothing exciting about and just average for late August here, plus the warmth of 22-23C are crumbs from the 30-31C heat just next door to us.  Not acceptable so glad to see the back of it on 1st September. 

It's disappointing that it's taken until virtually the end of summer before we're likely to get a nationwide settled spell according to the models, but better late than never I suppose.

That said, I've seen a decent September spell come on the back of a poor summer/poor August before. Last year saw a good September follow a cooler than average and rather mixed August, and back in Sept 2004, the dreadful August we had that year was followed by a glorious spell up here in the early part of that month. 2002 was another year that had a poor summer here but then a good September.

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 SUNDAY AUG 30TH 2015

THE CURRENT GENERAL SITUATION A trough of Low pressure will lie across Southern England today and tonight with a complex if shallow Low pressure forming along it tomorrow before the whole system slowly edges away East later

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 shows a very complex pattern to the flow over the coming two weeks. The current SW to NE flow across the South weakens in the coming days with the main thrust of the flow well to the North of the UK later this week. Complexities arise thereafter with a potentially strong flow over the Atlantic split North or South of the UK due to higher pressure to the North or NE.

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 before moving to the North and NE of the UK later. The thundery rain of today and tomorrow across the South and SE should give way to showers on Tuesday as the Low responsible for the rain drifts NE into the North Sea  and deepens. This then remains low moving for some time before it fills and drifts back South keeping the South always at risk from showers while the North remains locked under High pressure with fine conditions. It looks like becoming cool everywhere in a North then NE breeze. Week 2 still keeps the best weather over the North while the South remains at risk from showers reinforced by further Low pressure to the SW and South. Then right at the end of the run changeable conditions in a return to Westerly breezes affects all areas.

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

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

THE GFS CONTROL The GFS Control Run today shows virtually the same pattern as the operational through the coming week with North is best for the driest and brightest weather while the East and South remain plagued by Low pressure just to the East and SE with cool breezes and showers at times. It differs from next weekend though as the Atlantic becomes influential across all areas again as Low pressure fills the void left from this weeks filling Low pressure and brings rain and showers to all areas again. It will feel cool for much of the time especially at night and in the NW through Week 1 closest to High pressure to the North and West.

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show a fairly even split again with the UK lying either under a ridge between High pressure to the NE and SW or a more direct westerly flow under Low pressure to the North. 15% of members show High pressure across the UK with fine and warm conditions as a result.

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 a cool week across the British Isles with the UK sandwiched between High pressure to the West or NW of Scotland and Low pressure over Germany and the continent in general. A NNE flow across the UK should deliver a lot of fine and cool weather with jolly chilly nights but some showers are possible in the East and South at times.

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

THE FAX CHARTS The Fax Charts this morning replicate the raw data fairly well this morning with the reluctance to push Low pressure to the East of the UK far enough away to allow the influence of High pressure to the West and NW. As a result a cool NNE flow will develop early in the week and last through to the weekend with cool and breezy weather with some showers in the East and South with some very cool nights in the clearer NW.

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

GEM GEM too today fails to show the High pressure zone forming to the West any chance of ridging across the UK as Low pressure remains stubbornly anchored across the North Sea and even gains support from a new incursion from the North later next weekend to keep cool and showery conditions across most areas over most of the period with a brisk breeze blowing from a Northerly sector only becoming replaced by SE winds and falling pressure to the SW late in the period as rain moves in from that direction then.

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

NAVGEM NAVGEM follows a similar theme to UKMO with a weaker area of Low pressure across mainland Europe. It allows the High to the West to inch towards the UK through the week but insufficient to prevent northerly winds being maintained across the UK with showers more and more confined to the SE by next weekend.

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

ECM ECM this morning shows a halfway house between GFS and UKMO this week with the slow rise of pressure indicated through the week but not before Low pressure over the North Sea over the midweek period gives some cool, breezy and showery weather for many. The High to the West then migrates to the NE and settles North of Scotland veering winds to the East across the South still with the risk of showers feeding across from nearby Europe in the SE. At the end of the run pressure falls to the SW too and Southern Britain could be attacked by more wind and rain from the South or SW soon after the end of the period.

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

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from this morning continues to endorse the prospect that the UK could lie under High pressure in 10 days time though there are suggestions of a slight weakening of the pressure pattern by around that time.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models have lessened 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 95.9 pts and GFS at 95.0 pts. At 5 days UKMO is king at 86.8 pts followed by ECM at 86.3 and GFS at 83.8 pts. Then at 8 Days ECM still leads at 61.6 pts over GFS's 53.3 pts. Finally at Day 10 ECM leads GFS at 42.0 pts to 35.9 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 Today's output is split with a worrying half of the output from GFS (both operational and control runs) along with GEM showing a deep Low over the North Sea blocked through this week and preventing much interest for many from High pressure to the West maintaining a cool Northerly flow with showers for much of the time. However, both the big powerhouses of UKMO and ECM which UKMO interestingly has been outperforming ECM of late at 5 days range shows a more modified area of Low pressure over Northern Europe allowing the High to make some progress into the West and North of the UK later in the week. Once again I expect short term forecast changes in the weather to occur again this week as the hemispheric pressure patterns continue to be somewhat unusual and stubbornly misbehaving of late.

So in weather terms as I quoted in my reports midweek my feeling then was we would have trouble over this weekend from the frontal boundary to the SE and this has proven to be the case with energy continuing to run NE along it over the coming 24-48hrs affecting the South and East before forming a closed Low centre near the SE which moves NNE into Denmark by Tuesday. From that point on there are differences between the two groups of output with the GFS camp delivering the UK a cool northerly flow all week and into next weekend with showers a risk for all areas at times. In the Euro's camp a much more open area of Low pressure to the East allows higher pressure to the West to bear some influence for many with dry and bright weather with just a few showers towards the East along with lighter but equally cool winds. Then longer term we see various evolutions, all of which are credible given the pattern we have but none that can be taken too seriously at this range. So in a very complex nutshell my best stab at the forecast for the next 10-14 days is North and West being best with sunshine and dry weather but with jolly cool nights and none too warm days while the South and East while also seeing dry, cool and fine weather at times are at greatest risk of showers from pressure being low over the nearby continent.

Next update from 09:00 Monday Aug 31st 2015

Thanks, Martin.

My guess for that low pressure centre over Denmark/ the North Sea is, that having developed more strongly than was indicated a few days ago, it's more likely to stick around and indeed intensify. So, regretfully, a miserably cold few days for the East Coast and some rain from time to time as well.

Hints on the BBC forecast last night that the combination of  current high spring tides and northerly winds could give minor coastal flooding in places.

Will be a pity if skies are mostly cloudy as it will stop minima from getting too low - Could be some impressively low temperatures otherwise.

Shouldn't be that bad ad September always deliver wall to wall sunshine easier like Spring.  I expect temps to be warmer than this weekend temps due to more sunshine and cooler nights.  I prefer 5-8C to 18-21C than this weekend 13-15C and 16-18C with faux 15C uppers.   06z keep the good theme for most with northerly bringing clear skies then continue the same as drier easterly winds from the continent later on with slowly warming up temperatures.

Yes, I'm devastated that temps might not get too low. Traumatised even...

Entertaining if this lasted through the winter months. Can imagine some people getting very upset if it's mild and wet in the west whilst Kent and Essex get occasional spells of snow. 

Of course, daytime temperatures will be more suppressed if it's cloudy... I'd have thought you'd prefer impressively cool and clear nights but reasonably warm feeling and sunny day's over milder, cloudy nights and chilly, overcast day's?

You pay's your money and take's your choice I guess...

Definitely not. I don't want chilly weather ever. It's why the last two winters have been so amazing. 

I was going to suggest something similar earlier Brian but refrained for fear of reprisals. It's an interesting thought .