Model Output Discussion - 1st August 00z---------->

[knocker]

Could be some nasty weather on this lot

 

 

[Summer Sun]

Saturday could be the hottest day widely in England and Wales for quite some time

 

 

At the stage the rain stays in the west which I've posted in the storm thread

[The PIT]

Saturday could be the hottest day widely in England and Wales for quite some time

 

 

At the stage the rain stays in the west which I've posted in the storm thread

I think the gfs is being over optimistic with those values away from the south east. You certainly won't get those near where the rain is. Local met office forecast has a max of 21C for us rather than 24C to 25c.

[I remember Atlantic 252]

I think the gfs is being over optimistic with those values away from the south east. You certainly won't get those near where the rain is. Local met office forecast has a max of 21C for us rather than 24C to 25c.

 

agree with that, every bbc update has given me 20-22C max, GFS has hot air too far west

[knocker]

I think you will find they have amended that. Regarding the rain on Sunday the METO are holding back on warnings until there is more certainty regarding the pivotal point of the fronts where there could be 24hrs of persistent rain.

 

Edited August 20, 2015 by knocker

[cheese]

I think the gfs is being over optimistic with those values away from the south east. You certainly won't get those near where the rain is. Local met office forecast has a max of 21C for us rather than 24C to 25c.

What makes you think they'll be right? Their automated forecasts are mostly rubbish.

[bryan629]

Agree with that cheese... 

 

A very tricky forecast for the weekend.. i do think the gfs is overplaying the distribution of warmth/humidity to far west though. 

 

well according to the deputy forecaster at the meto... heres their take on things.. 

 

https://www.youtube.com/watch?v=RkAcbZ7YRPE

[Sunny _Android]

The MetO has me (Warrington) down for the best temperature on the 22nd at 18C at 01:00, the rain takes hold and that temperature remains down below 18C all day !

 

Even GFS has the rain here so I'll be watching for any slight improvement or perhaps the reverse, with warnings from the MetO with great interest this weekend.

[Scorcher]

I think the gfs is being over optimistic with those values away from the south east. You certainly won't get those near where the rain is. Local met office forecast has a max of 21C for us rather than 24C to 25c.

 

Think the BBC/Met may be being too pessimistic as they usually are though- they were already showing the band of rain on Saturday as being further west than they were first thing this morning on the national forecast this evening. 

[Man With Beard]

Latest GFS has rain quite a way west on Saturday, still on West Wales coast at 2pm

[The PIT]

What makes you think they'll be right? Their automated forecasts are mostly rubbish.

Well trying to think of the last time we had values like that under rain. Errr never. Cloud cover looks pretty rebust before the rain arrives as well.

[Man With Beard]

No comments on the models this morning until now and I can understand why! The main trough gets far too close to the UK by Monday, and secondary lows come marching in one after the other until at least the bank holiday weekend. The GFS comes up with yet another wonderful la-la land ending. Honestly, the GFS post T168 has been atrocious this summer, far more than usual. If it had been right even 50% of the time, it would have been a sizzler of a summer. It's obsession with building high pressure up from the Azores has been wrong.

 

Edited August 21, 2015 by Polar Maritime
To remove unnecessary moaning.

[knocker]

Well I'm afraid I don't understand why. Agreed the outlook is dismal but that that surely doesn't detract from the the fact that, meteorologically speaking, it makes for interesting model watching.

Edited August 21, 2015 by Polar Maritime
To move discussion on.

[Gibby]

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 21ST 2015

 

THE CURRENT GENERAL SITUATION. A large depression South of Iceland will dominate the Eastern Atlantic and the UK with a warm and moist SW flow across all areas. A weak cold front will become slow moving over Western areas reinvigorating later in situ.

 

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

 

MODELS-2 WEEK HEADLINE Remaining somewhat mixed with a lot of dry weather for all but with occasional rain too at times.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the flow moving SE towards Spain before turning sharply North across the UK over the coming days. The flow then slowly veers to a more SW to NE flow across the UK later next week and further North still in Week 2 as High pressure builds from the South for a time.

 

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

 

GFS OPERATIONAL The GFS Operational Run today shows Low pressure developing over and eventually just to the North of the UK. This will bring very unsettled weather to all areas for a week or so with showers and longer spells of rain. While warm and humid in the SE to begin cooler and windy Westerly winds will blow for much of next week. Then over the Bank Holiday Weekend it looks like pressure will be building from the SW, too late for the start of the weekend but OK for the day itself with a spell of warm and sunny weather for many for several days. Then the end of the run shows a cold front moving South and an early season Northerly delivering cold Autumnal winds and showers to end the period.

 

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

 

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

 

THE GFS CONTROL The GFS Control Run today is only different in the second week as one would expect. It delays further the onset of High pressure from the SW bu once it does bring it in some very warm and sunny conditions look possible in Week 2 aided by an ex tropical storm to the West of the UK pumping up very warm air from the South over the UK with any rain from this restricted to the far NW.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning still look generally good in two weeks time with most members liking the idea of the close proximity to the UK of High pressure to the West and SW with any influence from the Atlantic restricted to more Northern areas.

 

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 looks very unsettled next week as the humid thundery airflow of the weekend gets swept away East by blustery and cooler West to SW winds with rain or showers at times for much of next week in association with Low pressure just to the North or NW.

 

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

 

THE FAX CHARTS The Fax Charts this morning show the week trough currently over Western Britain rejuvenating tomorrow as Low pressure forms along it to the South which then moves North across the UK and sweeps the trough East with a very unstable WSW flow across the UK to start next week.

 

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

 

GEM GEM today shows very unsettled conditions developing across the UK over the coming days as Low pressure develops and moves North over the UK setting up cooler westerly winds with rain and showers for all of next week. Improvements on this run are muted in regard to the Bank Holiday Weekend with lighter Westerly winds shown but still with enough instability across the UK for rain and showers to continue.

 

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

 

NAVGEM NAVGEM also follows the theme of Low pressure in control in a big way over the next 7 days with cloud and rain at times for all and temperatures after a warm and humid start falling to average at best in a developing blustery west or SW wind. Some limited improvements are hinted at for Southern Britain next weekend.

 

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

 

ECM ECM this morning too looks unsettled and breezy with the same Low pressure complex over Western Britain late in the weekend only slowly moving North with West or SW winds affecting all areas with rain and showers, especially towards the West and North. Warm air is shown to flirt with the SE again later next week but conditions are shown to remain changeable up to the start of the long weekend when High pressure over the Atlantic ridges in to the UK. pressure is low over Iberia though and this threatens the South with thundery showers come Bank holiday Monday with the North seeing the best conditions then.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening shows very slack conditions across the part of the Northern hemisphere around the UK with a slight bias towards lower pressure to the NW and higher pressure to the South. This is made up of members who show a variety of options where no one pressure pattern is established for that time.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models are all in agreement of a spell of unsettled and windy weather under Low pressure next week with some signs of slow improvements next weekend to rather better conditions to start September.

 

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 95.9 pts followed by UKMO at 95.6 pts and GFS at 94.7 pts. At 5 days ECM is stll king at 85.7 pts followed by UKMO at 85.5 and GFS at 82.9 pts. Then at 8 Days ECM still leads at 61.0 pts over GFS's 55.1 pts. Finally at Day 10 ECM leads GFS at 42.5 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 It looks pretty nailed on now that the UK is going to see a spell of potentially very wet weather in a few days with just location yet to be nailed down on where the heaviest rainfall will be, all this as a cold front engages some very warm and humid air moving North over the East of the UK from Europe. Thundery rain looks inevitable from tomorrow becoming widespread and heavy currently expected to be most likely across Central and Western areas as a Low develops and moves North along the axis of the front over the West. Then next week sees all the humidity swept away East with Westerly winds on the Southern flank of Low pressure anchoring to the North and NW for much of next week delivering further spells of rain and showers in blustery and cooler winds than of late. We then have to look at whether the models are still focusing on improvements for the Bank Holiday Weekend and on into September. In general they are but whether it is in time for the Bank Holiday Weekend is open for debate as there is some delay in this on today's output making the weather for the UK an improving scenario as the weekend moves on rather than a dry one from the start. Nevertheless, signs are encouraging that not unusually for this time of year the Jet stream may move North at the start of September which could allow the Azores High to ridge into the UK more meaningfully and give us a pleasant period of weather at least. No report tomorrow morning but back as usual on Sunday.

 

Next update from 09:00 Sunday Aug 23rd 2015

[Polar Maritime]

Well I'm afraid I don't understand why. Agreed the outlook is dismal but that that surely doesn't detract from the the fact that, meteorologically speaking, it makes for interesting model watching.

 

Exactly Knocker, An interesting week coming up for weather enthusiasts! A real complicated mix over the weekend with some heavy persistent rain stalling over the UK Sun/Mon. Next week certainly looks far more mobile than what we have endured during recent times at least. 

Edited August 21, 2015 by Polar Maritime

[legritter]

Morning fellow posters  ,i,v been lurking and enjoying our forum as of late .looking after my 93 yr old mother inlaw who is very frail ,but still gives me all the news of the Weather from her daily express and Sun newspapers ,[i do listen to her ] .well all Data and charts today paints a very interesting and possibly volotile outlook ,with i,m sure some news worthy weather coming up .

Detail of areas affected very hard to pinpoint ,but the  general ideal is one of low pressure before high pressure kicks in later in the outlook .

Bank holiday weather at this range could go many ways at 8 days start time till 10 days for our last bank hol monday , I would like to thank Gibby for the brilliant breakdown of the charts and all other posters that make this weather forum the very best , ps express just arrived so lets look at what the experts are saying ,cheers gang 

[Nouska]

No comments on the models this morning until now and I can understand why! The main trough gets far too close to the UK by Monday, and secondary lows come marching in one after the other until at least the bank holiday weekend. The GFS comes up with yet another wonderful la-la land ending. Honestly, the GFS post T168 has been atrocious this summer, far more than usual. If it had been right even 50% of the time, it would have been a sizzler of a summer. It's obsession with building high pressure up from the Azores has been wrong.

 

 

Maybe it should have been a sizzler of a summer....it was, not very many miles away!!

 

This raises the question of what the differences are between the GFS and ECM - ECM was less bullish about the high pressure but it was there - Met office updates and Knocker's run down on EC32, testament to that.

 

There is something going on in either the oceans or atmosphere (probably both) that the model algorithms are not handling well. Gibby quotes the NH statistics for the models; I wonder what they would look like in a narrowed wedge of the Atlantic sector.

 

It is not what people want to see but it is fascinating to watch - I can see the weather out the window - I want to know what makes it work the way it does, only models and research can do that.

[Nick F]

I have done a synoptic analysis of the coming weekend's tumultuous weather likely and a brief look at the weather beyond to the BH weekend in a blog here:

 

http://www.netweather.tv/index.cgi?action=news;storyid=6826;sess=

[Dorsetbred]

Thanks Nick great analysis as to a complex event. The timing of the pivot action seems to be a critical factor here in how much rain folks are likely to see. 

That low running up the channel also seems key in it's positioning for us coasties.

Edited August 21, 2015 by Dorsetbred

[knocker]

Maybe it should have been a sizzler of a summer....it was, not very many miles away!!

 

This raises the question of what the differences are between the GFS and ECM - ECM was less bullish about the high pressure but it was there - Met office updates and Knocker's run down on EC32, testament to that.

 

There is something going on in either the oceans or atmosphere (probably both) that the model algorithms are not handling well. Gibby quotes the NH statistics for the models; I wonder what they would look like in a narrowed wedge of the Atlantic sector.

 

It is not what people want to see but it is fascinating to watch - I can see the weather out the window - I want to know what makes it work the way it does, only models and research can do that.

 

Yes I agree Nouska. From where I'm sitting the simplistic explanation is they haven't handled the upper trough in the eastern Atlantic at all well. having said that time for another roll of the dice vis the Bank Holiday weekend and further.

 

The GFS, ECM and the EC32 anomalies are all going for starting a relaxation of the trough around Sunday accompanied by a weakening of the  Scandinavian ridge. This may be significant as it allows the cooler air Iceland area to sneak east and the Azores to ridge in from the south west. Yes I know we have all heard that before. So the way it looks at the moment, and this is just a general observation as this is a fair way down the line, dodgy for the beginning of the holiday but improving by Monday and continuing until the end of the week

http://www.tropicaltidbits.com/

[johnholmes]

Well as everone knows I tend to take the 3 main anomaly charts as a first class guide to what the upper air pattern is likely to be 6-15 days down from day1.

The EC-GFS have done another marked change, well EC has, over the past two days, see below for the output this morning, with a Greenland ridge being shown. Not shown on GFS nor NOAA so at the moment I would discount that, when looking over the past 4-5 days outputs from all 3. Of the 3, as is often the case, the NOAA ouput has shown less variation and is the one, in these situations, over several days, that I would believe more than either of the other two. See NOAA idea below, both 6-10 and 8-15 outputs.

As you can see the suggestion is for the maintenance of the trough west of the UK, no sign of any height rises let alone ridging, either from the Azores region nor Greenland. So I stick with NOAA until it suggests differently over at least 2 and preferrably 3 outputs.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

That of course is 6 days away and we have a fascinating period coming up in the next 12-96 hours, and surpiringly to me not a lot of interest being shown in this thread. The models are still not settled on the actual timing and weather sequence, neither are the Exeter folk as we see almost each TV broadcast they do-so very interesting to see just how this does play out.

Just noticed the post from Nick F with 10 'likes' well worth a read for those not having read it yet-thanks Nick

Edited August 21, 2015 by johnholmes

[Polar Maritime]

As has been stressed already, A very interesting weekend coming up for us weather enthusiasts, With storms pushing North on Saturday afternoon/evening/night bringing some very heavy rain/hail with localised flooding expected in places. Warnings are already out for most of England, Which I'm sure will be updated in time nearer the event. I think most will be glued to the radars as these will be home-grown storms which could pop up anywhere given the big temperature differences.

Edited August 21, 2015 by Polar Maritime

[knocker]

No huge change with the GFS for this weekend

 

By 00z Sunday the shallow low has developed in the western Channel and proceeds to move north then north east with the fronts orbiting around it. Quite wet in western parts. The next low then appears on the scene and tracks NE through southern England to East Anglia by 18z on Monday. Quite windy in the south west but the strongest winds are N. France with gusts up to 65kts. Of course the precise track is quite important in this regard.

http://www.tropicaltidbits.com/

 

[The PIT]

As has been stressed already, A very interesting weekend coming up for us weather enthusiasts, With storms pushing North on Saturday afternoon/evening/night bringing some very heavy rain/hail with localised flooding expected in places. Warnings are already out for most of England, Which I'm sure will be updated in time nearer the event. I think most will be glued to the radars as these will be home-grown storms which could pop up anywhere given the big temperature differences.

There's only one warning for SE. Anyway loads of uncertainty. Latest NMM for us indicates showers local forecast showers later on with a huge difference in temps.  GFS more organized rain. Take your pick.

[Milhouse]

It looks like Summer is putting in one last big effort to bring the UK some heat and storms. For eastern parts it looks very warm, even hot in places tomorrow and Sunday is looking fine too with the rain holding out to the SW before pushing back north later on. Very muggy tomorrow night with temperatures holding up in the mid to high teens.