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

[mushymanrob]

As expected any HP settling things down has been pushed away by a strengthening atlantic moving in, looks wet and windy next sunday/monday on UKMO/GFS 12Z.

Yep, but youre assuming that todays 12z will verify, of course its highly unlikely to verify a week away. Especially when such an evolution the 12z suggests has no support from the anomaly charts.

And it would be also true to say the same charts dont support high pressure dominance over the uk either, so those of us that follow the anomaly charts werent expecting high pressure to settle things down.

Its been clear now for the past few days that theres the age old tussle going on over the uk between a strong scandinavian high and deep atlantic trough. Nothing settled there.

[Nouska]

Afternoon all

 

The 12Z rolling out at present but the 06Z a classic JTC (Jam Tomorrow Charts) with plenty of settled HP-dominated weather in low-res but the immediate future much more uncertain and unsettled:

 

 http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

 

Probably not of huge relevance at the moment but the ongoing split between HP to the NE and SW and LP to the NW and SE leaves Britain in the classic COL or No Man's Land. 

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015081700/ECM1-144.GIF?17-12

 

This morning's ECM for next weekend reflects both the negative NAO with the trough dropping well to the south and the very light winds associated with the Col. 

 

http://modeles.meteociel.fr/modeles/gem/runs/2015081700/gem-0-150.png?00

 

GEM not very far away from that either.

 

http://www.meteociel.fr/ukmo/runs/2015081700/UW144-21.GIF?17-06

 

UKMO more extreme if anything with the centre of the LP well south.

 

The GFS 06Z provides a way out which would be wholly favourable by providing some energy off the eastern seaboard which pushes the Azores HP NE to merge with the Scandinavian HP and set up shop over the UK. Given we are at the time of year when tropical systems get involved it's not a wholly improbable scenario and may be one reason we often get decent September and October spells - I wonder if there is a correlation between the path of active tropical features and the recurrence of HP around north and north-west Europe.

 

Just as you say that, GFS models the first MDR (main development region) system of the season.

 

 

It is a very inhospitable environment down there so could be waiting a while to get something to shake up the pattern.

[Polar Maritime]

Yes a real mix up going off next weekend, With Lows rotating over or near the UK. A complicated mix of signals at this range, So i would take it purely as that. But interesting nevertheless..

Edited August 17, 2015 by Polar Maritime

[knocker]

I have that deja vu feeling all over again.

 

On Sunday trough in charge of affairs which ties in with the latest ops run. Thereafter a gradual improvement with the trough retrogressing and a ridge to the SE. This continues with the trough weakening and the Azores ridging into the UK by Sep. 01st.

 

I've said this so often this summer I think I'll just concentrate on this weekend for the moment which is, I'm afraid, looking a bit dodgy

 

A quick look at the ECM ops and though a little different to the GFS a similar outcome.

http://www.tropicaltidbits.com/

Edited August 17, 2015 by knocker

[Man With Beard]

Ok - two nights ago we were looking at reverting to type (NW trough), last night looked like a cut-off low bringing heat across the UK. Now we have something different again - an autumnal run of low pressures flying in at the UK and deepening over that same dodgy area of the Atlantic that has ruined the chances of long-term good weather over the UK this summer. Here is one of the ugly scenes from tonight's ECM:

 

meteociel.fr/modeles/ecmwf.php?ech=144&mode=1&map=0&type=0&archive=0

 

Total lack of consiste​ncy in the models, but looking un-good in all honesty - the cut-off low now seems totally off the table having seemed so plausible last night - we seem more at risk of the shed blowing down. Still 4/5 reasonable days coming up for most.

​

[BLAST FROM THE PAST]

Keep your eyes peeled for this beauty, I anticipate confirmation and a nasty couple of days.

 

 

edit...ecm has it too...

 

BFTP

Edited August 17, 2015 by BLAST FROM THE PAST

[William of Walworth]

Looking like any chances (at this stage) of almost anywhere in the UK staying DRY in the Thursday 21st to Monday 24th of August period look pretty damned low** on most of the latest output.

 

**being the operative word.

 

My area of (personal) interest for the coming weekend is the South Devon/Exeter area. Any hopes of anything more benign developing for the above period round there? Right now I'm not seeing this ...

Edited August 17, 2015 by William of Walworth

[Cloud 10]

Maybe still a chance for a late plume towards the end of the month as advertised by the 12z gfs ...

 

 

....must have been quite a few amongst the ecm ensembles to come up with this.

 

[BLAST FROM THE PAST]

agree with Cloud...have booked some leave

 

BFTP

Edited August 17, 2015 by BLAST FROM THE PAST

[knocker]

Looking at the latest fax chart for 12z Saturday finds a frontal system over the UK with depression to the west in mid Atlantic.This mornings GFS is more or less on the same page.

 

Now run the sequence on 12 hours and the depression is moving east towards the UK whilst a shallow low also moves up from France. By 00z Monday the shallow low has travelled north to northern Scotland whilst the filling Atlantic low is poised near Lands End.

 

To sum up. Saturday might not be a bad day, indeed it could get quite hot in the SE, maybe high 20sC, but Sunday and Monday have the hallmarks of being quite wet.

Charts weatherbell

Edited August 18, 2015 by knocker

[knocker]

Needless to say the ECM has different take on the weekend. Sunday 00 finds a deeper low west of Ireland with the shallow European low in the Low Countries. The main low low moves NE to be north of Scotland by Tuesday 00z.with another low appearing on the scene WSW of the UK. Within 24 hrs this low is over western Ireland leaving the UK in a south westerly air stream

http://www.tropicaltidbits.com/

 

[johnholmes]

None of the anomaly charts gives any hope of ridging or +ve heights close enough As knocker shows above the Fax chart  for Saturday simply puts in picture form what we can expect. to the UK to over-ride the trough/cut off low showing on the 500mb charts in the 6-15 day period.

Obviously the detail on actual positions of lows and fronts will not be clear for a day or two but no heat wave seems likely this coming weekend.

links below

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

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

Edited August 18, 2015 by johnholmes

[Roadrunner]

None of the anomaly charts gives any hope of ridging or +ve heights close enough As knocker shows above the Fax chart  for Saturday simply puts in picture form what we can expect. to the UK to over-ride the trough/cut off low showing on the 500mb charts in the 6-15 day period.

Obviously the detail on actual positions of lows and fronts will not be clear for a day or two but no heat wave seems likely this coming weekend.

links below

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

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

John, am I right in thinking things are still looking poor for the weekend then!

[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 TUESDAY AUG 18TH 2015.

 

THE CURRENT GENERAL SITUATION. A Low pressure area will move NW up the North sea filling later. Anoher Low's troughs will approach the West of the UK from the Atlantic tomorrow. An area of slack pressure will persist across the UK today.

 

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 main arm of the flow moving SE over the Atlantic to the Pyrenees with a returning arm North over the North Sea. The flow simplifies later in the week with the main thrust NNE across the UK come the weekend. Then next week it weakens and relocates further to the NW for the latter stages of the period.

 

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

 

GFS OPERATIONAL The GFS Operational Run today shows High pressure to the NE. A deep depression given the time of year to the NW then swings troughs East across the UK through the latter stages of this week in a mild and muggy SW flow. Through the weekend and early nxt week Low pressure is shown to be in control of the weather for all with various centres near or over the UK. Thereafter the trend is for pressure to rise strongly across the UK in the second half of the run with High pressure and warm and settled conditions looking likely towards the end of the period and including the Bank Holiday weekend.

 

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

 

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

 

THE GFS CONTROL The GFS Control Run today shows a similar theme as the operational run through Week 1 but is less optimistic through Week 2 as it maintains Low pressure close to the South of the UK at times with rain or showers here while the North see the best of the dry weather under the influence of High pressure to the NE and East. The end of the run shows a slack and cooler Northerly over Britain ahead of a ridge of High pressure moving in from the West. 

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show a split in members almost equal to one another. One half illustrates High pressure lying over or close to the UK with fine and dry conditions for most as a result while the other half of members show Low pressure up to the NW with Westerly winds and 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 Low pressure up to the NW later this week and the weekend culminating into a nasty little Low swinging NE into Scotland to start next week. The net result will be rain or showers for most especially towards the North and West with the possibility of gales and heavy rain for many for a time early next week.

 

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

 

THE FAX CHARTS The Fax Charts this morning show very changeable conditions developing later this week as troughs of Low pressure move in from the West and become hung up across Southern areas maintaining cloudy, humid and damp conditions for several days before fresher air is pushed East behind a cold front at the weekend. then a deepening Low is shown swinging towards Western Britain to end the 5 day period.

 

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

 

GEM GEM today also shows changeable weather in SW winds from tomorrow on for all areas but taking it's time to reach the extreme SE. This model too shows a rapidly deepening Low swinging into the UK to start next week with rain and gales possible. On the exit ofthis Low the pattern reverts to a NW/SE split in conditions with further changeable weather in SW winds for many but a lot of dry weather in the SE.

 

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

 

NAVGEM NAVGEM doesn't show the active Low to start next week that most other output shows. What it does show is the parent Low to the NW later this week sinking South and East to lie across the UK a week from now ensuring all areas see rain or showers at times in generally West or cyclonic winds.

 

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

 

ECM ECM this morning shows the deepening Low early next week replacing the previously changeable weather with occasional rain to something much more Autumnal for a time as gales and heavy rain sweep NE through all areas for a time. Thereafter a changeable regime remains under Low pressure close to or over Northern and Western Britain with rain at times, heavy and thundery on occasion as warm air flirts with the SE at times.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening shows Low pressure West of Scotland with SW winds across the UK. With pressure relatively Low across the UK in a SW flow some rain at times can be expected for all especially towards the North and West with the warmest weather still towards the SE though even here rain at times looks probable.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models are coming together in showing a rather deep Autumnal Low passing over the UK early next week with much indecision on specifics in the period that follows.

 

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 95.8 pts followed by UKMO at 95.4 pts and GFS at 94.6pts. At 5 days ECM is stll king at 85.6 pts followed by UKMO at 84.8 and GFS at 82.9 pts. Then at 8 Days ECM still leads at 60.0 pts over GFS's 54.2 pts. Finally at Day 10 ECM leads GFS at 41.1 pts to 36.3 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 Irrespective of weather events shown by the models for the coming two weeks the solar clock is ticking as we drift towards celestial Autumn. However, we have two weeks of summer left but somebody seems to have forgotten to tell the models as they have served up another cocktail of charts which in the later days of the run are as confused as ever on the likely weather in two weeks time. What they do agree on this morning unfortunately is that over the next 7 days or so the weather is going to turn more unsettled and eventuually very unsettled. A deep Low to the NW will become the dominant player of the UK weather from tomorrow as it pushes fronts across the UK from the West which then become slow moving near the South for several days. This means rain will march East across the UK from tomorrow but be slow to reach the far East and SE where it will stay warm and humid until the weekend. At the weekend a change to cooler and fresher conditions seem likely as a cold front clears East which makes way for the highlight of the model runs this morning which is the passage NE of a potentially deep and Autumnal looking Low early next week which depending on track and depth could give rise to copious rainfall and gales almost anywhere for a time. Then from that point on the models diverge with various options shown ranging from Westerly winds and the familiar NW/SE split re-establishing  to full blown High pressure lying across the UK to end the month with fine, warm and settled weather for all inclucing the Bank Holiday. So in a nutshell there is still a lot of fog to clear from the models and their projection for beyond a week of the present. Nevertheless there seems enough common ground between them to suggest that the Atlantic is most favoured to continue governing the weather at the end of the month with nothing particularly special being advocated in respect of very high temperatures to end Summer, at least on a UK wide scale. Interestingly the verification stats show that ECM remains the best throughout the 10 day period with a 60 pts success rate (the highest for 6 months) at Day 8 with GFS only clocking 54 pts. So those people who says all the models haven't got a clue need to look at the 10 Day mean Chart from ECM which despite the chopping and changing of other output in relatively short time spans this Summer ECM has maintained Low pressure up to the NW for what's seem to be an age this Summer at the 10 Day range and looking back on the weather realised this Summer it has been proved to be correct more often than not and nothing on this morning's output makes me think that synoptics in 10 Days time will look significantly different to what it shows again today.  

 

Next update from 09:00 Wednesday Aug 19th 2015

[johnholmes]

John, am I right in thinking things are still looking poor for the weekend then!

 

I suppose it depends on the definition 'poor' but if its sun and heat the yes as it is looking at the moment I am afraid.Although the SE corner may not fare too badly on current charts.

[Nick F]

Some notable differences between 00z GFS and 00z ECMWF operationals by the weekend with regards to surface pressure and fronts. GFS has a shallow thundery low drifting north from western France across S England on Saturday ahead of thermal/cold boundary which is slow-moving to the west, before shifting east on Sunday introducing cooler and fresher conditions for all. ECMWF doesn't have this shallow low drifting north and is more progressive with pushing cooler and fresher conditions east on Saturday after warm up in the east towards the end of the week. 00z UKMO looks similar to ECM.

 

Be interesting to see which models is closer to the truth, would prefer the GFS option personally, as it would bring some brief heat and risk of thunderstorms before fresher conditions arrive Sunday. ECMWF looks rather more benign with the frontal transition.

[Nouska]

GFS blasts my home country with a northerly to see out a poor summer and then builds a very traditional start to Autumn with a warm anticyclone and a hurricane churning in the Atlantic.

 

It wouldn't be the first time the pattern has suddenly switched with the seasons - time for some warmth and dry weather for the folks back home.

 

  

[Winter Cold]

Afternoon all.

 

Just ran through the models, and pretty good agreement 6 days out for a nasty day next Monday! First Autumnal storm? Better next Monday than the one after though as this would have been a washout Bank Holiday......

 

     

 

 

Still lots of time for change obviously but its not often you see agreement like that at this timescale.

Edited August 18, 2015 by Winter Cold

[stainesbloke]

Afternoon all.

Just ran through the models, and pretty good agreement 6 days out for a nasty day next Monday! First Autumnal storm? Better next Monday than the one after though as this would have been a washout Bank Holiday......

Still lots of time for change obviously but its not often you see agreement like that at this timescale.

Quick question (not a moan): if these charts were to verify as shown 6 days away (as I fully expect them to), how come the high pressure frequently modelled in the 5-8 day timeframe this summer has repeatedly failed to materialise? I would have thought it would be much harder to predict these deep lows rather than anticyclones?

Edited August 18, 2015 by stainesbloke

[Summer Sun]

Afternoon all.

 

Just ran through the models, and pretty good agreement 6 days out for a nasty day next Monday! First Autumnal storm? Better next Monday than the one after though as this would have been a washout Bank Holiday......

 

     

 

 

Still lots of time for change obviously but its not often you see agreement like that at this timescale.

 

A bit different on the 12z from whilst still unsettled pressure isn't as low

 

 

GFS hasn't really changed though

 

Quick question (not a moan): if these charts were to verify as shown 6 days away (as I fully expect them to), how come the high pressure frequently modelled in the 5-8 day timeframe this summer has repeatedly failed to materialise? I would have thought it would be much harder to predict these deep lows rather than anticyclones?

 

The easiest answer I think would be the jet stream not going far enough north to allow high pressure a chance to build

[johnholmes]

Certainly an interesting few days model watching as the 'big' 3 decide just where the suggested low will track. Also just how much and where will any rain fall.

[Milhouse]

The GFS 12z has winds once again turning SW next week after an unsettled weekend. Some very warm, moist and humid air being scooped up and pushed northwards.

 

[Frosty.]

The Gfs 12z shows an anticyclonic early September with high pressure building in and intensifying over the UK with max temps into the low 20's c but cool nights under clear skies, especially in the north. As for closer range, there are some occasionally dry, sunny & very warm and hot days across the s/e, the first of which is Saturday and then again at times next week but we are in for an unsettled spell with variable temperatures and sometimes breezy/windy but summery weather too, the southeast quarter of England has the best of it on this run with the northwest, as usual being coolest and most unsettled until the end of August.

Edited August 18, 2015 by Frosty.

[I remember Atlantic 252]

Good B'day chart for me Frosty! 1st one

[William of Walworth]

Looking like any chances (at this stage) of almost anywhere in the UK staying DRY in the Thursday 21st to Monday 24th of August period look pretty damned low** on most of the latest output.

 

**being the operative word.

 

My area of (personal) interest for the coming weekend is the South Devon/Exeter area. Any hopes of anything more benign developing for the above period round there? Right now I'm not seeing this ...

I posted the above last night  (21:42 Monday) more in desparation, than in expectation of any improvement.

 

I'm seriously expecting a washout at points over the coming w/e.

 

But, just to strawclutch (only!), the BBC basic forecast for Exeter (UKMO based but obviously much simpler) for the relevant few days, the most recent one updated at 6 pm today I think, does not actually look too wet.

 

Is South Devon have any serious prospect of avoiding the worst? I very much doubt it, and in fact I'm steeling myself for deterioration in coming hours/days given how much wetter most other recent models are looking.

Edited August 18, 2015 by William of Walworth