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

[Summer Sun]

This is what GFS yesterday for tomorrows temps

 

 

And this is what it has on todays 12z

 

 

Not a great deal of change some places in the SE could make it into the low 30's

[knocker]

The shenanigans of the next few days seem to have heralded a pattern change with the upper air set up according to this evening's GEFs anomalies. One which has been hinted at previously but we have to get NOAA on board.

 

At day ten we now have low pressure over the Pole with a trough Alaska, no ridge NW America and the trough in the eastern Atlantic has moved east replacing the Scandinavian block.

 

This should allow a westerly zonal flow with the Azores HP to the south west being quite influential with any surface troughs relegated to the north and east. This would be good news for the latter half of the Bank Holiday. Well one is allowed to dream.

Charts weatherbell

[johnholmes]

I thought that is what the 8-14 showed last evening, after several days with the trough west of the UK being dominant with a flow from south of west. It seemed a consistent chart having watched how the trough had been changed slowly over the previous days?

What it has not so far suggested is any sign of a ridge at 500mb or even +ve height values in the Azores area.

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php

Edited August 22, 2015 by johnholmes

[Milhouse]

Azores high...the violin of Summer that teases prompts..,but naturally fails to hit the Uk and bring settled weather for more than a day overall...Its been a torment, torture, for those looking at a prolonged summer with lovely temps

 

Its been a reasonable summer over here so it just shows you dont need high pressure overhead to deliver summery conditions to parts of the UK. But to get nationwide settled weather we do need that elusive high positioned on top of the UK. And not for the first time in recent years, the ECM has high pressure becoming dominant on the last day of summer But at day 10 its subject to a high degree of uncertainty. 

 

 

Some very warm and humid air being dragged northwards next week, but it wont necessarily translate into high temperatures by day, but night time minima would be held in the high teens id imagine under all the cloud.

 

[knocker]

The ECM anomaly is on the same page as the GEFs. A suspicion of positive heights to the west? I'd settle for this over the Bank Holiday.

Charts weatherbell

 

[knocker]

No agreement between the METO and this morning's GFS over the evolution tomorrow.

 

The fax charts have the wave depression running NW into eastern Ireland 994mb by 12z, with the cold front from there to Kent, and then west to western Ireland 985mb by Monday 00z. The other low winging up from the SE to be over SE England 998mb by midday Monday.

 

The GFS runs the wave NW and has it 998mb northern Ireland with cold front orientated SE through Wales and Dorset by 12z Sunday. It continues to to move it NW whilst tracking the other low into central southern England 988mb by 12z Monday.

 

So even at this late stage no agreement on the movement of the cold front as it swings through England nor the track and depth of the second depression.

http://www.tropicaltidbits.com/

Edited August 22, 2015 by knocker

[mushymanrob]

O thought that is what the 8-14 showed last evening, after several days with the trough west of the UK being dominant with a flow from south of west. It seemed a consistent chart having watched how the trough had been changed slowly over the previous days?

What it has not so far suggested is any sign of a ridge at 500mb or even +ve height values in the Azores area.

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php

 

yep, thats what i thought this morning, no support for the ridging azores high the ops suggest beyond day 8.

another instance arising, have the ops picked up on something before the noaa anomaly charts? or will the anoms be proven to have a better handle on the final solution.

[knocker]

yep, thats what i thought this morning, no support for the ridging azores high the ops suggest beyond day 8.

another instance arising, have the ops picked up on something before the noaa anomaly charts? or will the anoms be proven to have a better handle on the final solution.

 

Well I don't know about that.

 

The ECM has a similar take as the METO tomorrow.

Edited August 22, 2015 by knocker

[Summer Sun]

A straw clutch for BH Monday and early September on ECM

 

 

Temperatures nothing special but at least it would be dry and still pleasant enough in any sunshine

 

GFS also shows things settling down as we move into Autumn

 

[johnholmes]

my notes below after spending time looking at the 3 main anomaly charts and synoptic outputs from EC and GFS over the past couple of days.
Sat 22 aug
Ec-gfs

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html
Well today and they both show some indication of the ridging/+ve heights ec had yesterday, and to some extent they each had for a couple of days before.
Both suggest a flow n of w into the uk as a result.
Until noaa shows this I am not taking ec-gfs idea as the most likely solution. Their persistence, not consistent over several days with one another though, does lend some doubt as to what may happen
Also to possibly back up ec-gfs charts is the fact that, using the 00z output, both ec and gfs synoptic models are pretty closely aligned with this idea out to 240h. That said though, neither of them at 12z Thursday showed a similar idea and not consistent prior to that either.
So I sit on the fence at the moment tending towards the NOAA solutution until it changes, if it does. It would not be the first time since the GFS update last autumn (was it?) for the synoptics to lead the way ahead of the anomaly charts. Three times I think and in the previous 6 years of checks only 2 possibly 3.

 

fine mate except for some reason the words are pretty small so I've taken the liberty of increasing the size?

Edited August 22, 2015 by johnholmes
Attached the 22nd August EC-GFS chart and link (hope that was okay). :)

[gottolovethisweather]

The near term.

 

Just posted this up in the CSE & SW thread but thought I'd post it up in here as well.

 

So just watched the latest TV forecast, which went a little something like this, hit it.  

 

• This PM - rain out West some heavy bursts within it, isolated showers, some downpours with Thunder and strong winds further East. Temps nudging 30c in some prone locations.  
•  
• This evening into Tonight - rain up from the Channel affecting western parts due West of Newbury judging by the predicted animations, all of this drifting Westwards into the overnight period, some Thunder embedded within this system.  
•  
• Tomorrow - A thoroughly wet day overall for most parts of Southern and SW England after what will be a very muggy night with Temps no lower than 19/20c in some parts. Increasingly windy in this system especially nearer the coast.  
•  
• Tomorrow night - Another band of rain incoming once the first batch clears Northwards, turning windy again, potentially very windy for time of year.  
•  
• Monday/Tuesday - Further bits and pieces of rain about over most parts and much cooler by now.  

 

An interesting period upcoming for sure and some Thundery action for a few of us whilst simply very wet for a whole lot of us.

Edited August 22, 2015 by gottolovethisweather

[Eugene]

Monday looks dare i say it autumnal with some strong winds and heavy rain, some tentative signs of the mythical cool and sunny weather bank holiday onwards, lets see if it arrives.

[mushymanrob]

Monday looks dare i say it autumnal with some strong winds and heavy rain, some tentative signs of the mythical cool and sunny weather bank holiday onwards, lets see if it arrives.

 

who cares?, we are getting some bonus heat and thunderstorms

[Man With Beard]

Many of the main models going for mid-Atlantic pressure rises by end of the week, leading to an eventual NW flow. UKMO not so sure. I'll stick my neck out and say it's still a doubtful solution, simply because the models have failed to pick up on so much mid-Atlantic activity this summer. I favour a flatter solution, and a westerly flow. But we'll probably know in 48 hours

[mushymanrob]

Many of the main models going for mid-Atlantic pressure rises by end of the week, leading to an eventual NW flow. UKMO not so sure. I'll stick my neck out and say it's still a doubtful solution, simply because the models have failed to pick up on so much mid-Atlantic activity this summer. I favour a flatter solution, and a westerly flow. But we'll probably know in 48 hours

 

agreed, and the noaa charts support that and not any sort of +ve height rises to our west

 

although the 8 - 14 day chart appears to suggest less troughing, pretty much in line with the gfs 00z.

 

[knocker]

Oh the joy of model watching. This mornings GEFs anomalies indicate improving weather for the latter half of the holiday but the ops has a nasty low nipping up from France. An excellent example of ignoring the evolution of one run on that time scale. Of course it could be right.

Chart weatherbell

http://www.tropicaltidbits.com/

 

[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 SUNDAY AUG 23RD 2015

 

THE CURRENT GENERAL SITUATION. Complex Low pressure will be centred around or over the UK for the next 24 hours or so followed by a cooler and fresher Westerly flow later tomorrow.

 

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

 

MODELS-2 WEEK HEADLINE Remaining very unsettled this week with rain at times. Perhaps rather drier as we move into September.

 

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast still shows the flow inappropriate for the UK to sustain dry weather for any length of time over the next few weeks. It lies across or to the South of the UK early this week with cyclonic conditions over the UK. With time it drifts North but never far enough to the North to sustain anything other than drier phases for the UK as a whole. 

 

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

 

GFS OPERATIONAL The GFS Operational Run today shows well in control of the UK weather over the next week as the thundery complex of Low pressure currently near the South of the UK drifts North and deepens to allow fresh to strong West or SW winds and cooler weather with showers or spells of rain at times throughout this week. Through the Bank Holiday Weekend further Low pressure is shown developing near Southern Britain with further thundery rain which delays yet again the onset of higher pressure for the second week which is still shown to at least give the South a spell of better early September conditions to finish 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 little different for Week 1 but is better for next weekend with less made of Low pressure developing over the South. In fact with High pressure not that far off to the SW plenty of dry and benign conditions look possible over the weekend and this is shown to improve further through the second week as High pressure migrates East across the UK to lie to the East later setting up some more humid Southerly winds late in the period with some rain from troughs in the West but dry weather over the East and SE.

 

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning show a 65% /35% split in members  this morning with the largest bias towards a lot of High pressure lying across the UK with some warm and settled weather in 14 days. The 35% that show less settled weather show a strong Low pressure area either over or to the NW of the UK with strong winds and rain at times for most of not all 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 changeable and often windy week with temperatures falling back to average in a blustery West flow with showers or longer spells of rain especially across the South at first and the North later as pressure begins to build from the South towards next weekend.

 

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 a much improved outlook for the British Isles eventually but we will have to be patient and it may not be soon enough to rescue the bank Holiday Weekend. In the meantime much of this week is shown to be cool and windy with showers or spells of rain, heavy at times with a gusty west wind developing. Then from next weekend pressure steadily builds from the SW with High pressure developing across the UK when we all go back to work with increasingly fine, sunny and warm weather developing for all.

 

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

 

NAVGEM NAVGEM is less rewarding for next weekend as it maintains something of a trough down the Eastern Atlantic just to the West of the UK with weak SW airflows but occasional rain at times with the warmest conditions in the SE, all this following a week of turbulent late Summer weather under the influence of strong Low pressure to the North and NW.

 

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

 

ECM ECM this morning takes a much more arduous route to somewhat better conditions in the second week I'm afraid.. This week is broadly similar to what the rest of the output shows which maintains very unsettled cyclonic conditions all week and with a small Low moving NE across the South early next weekend this looks unlikely to change much for many over the bank Holiday. Winds then switch to a chilly Northerly in the second week as High pressure inches towards the UK from the West but the air may be still unstable enough to support showers in the North and East at least.

 

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

 

ECM 10 DAY MEAN The ECM 10 Day Mean Chart  from last evening shows very inconclusive suggestions for the weather in 10 days. No doubt made up of members that support various scenarios for that time point the bias remains slightly in favour of a trough from the North down over the UK but with plenty of options pointing towards higher pressure and warmer conditions too.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models maintain the theme of a very unsettled and windy spell this week but still show the jury is still out on the extent on improvements thereafter.

 

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 96.0 pts followed by UKMO at 95.7 pts and GFS at 94.7 pts. At 5 days ECM is stll king at 86.1 pts followed by UKMO at 86.0 and GFS at 83.0 pts. Then at 8 Days ECM still leads at 60.7 pts over GFS's 55.1 pts. Finally at Day 10 ECM leads GFS at 42.9 pts to 37.5 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 Here we are at the start of a new week and another set of output which in the short term at least is far from what one would hope to see towards the end of August. The current thundery Low affecting the South and SW of the UK will move North and be superseded by a less thundery but still potent Low pressure tonight and tomorrow feeding more heavy rain and strong winds into those areas that have already seen quite a lot over the last 24 hours or so. Elsewhere away from the SW will see more rain from this feature than has been so far from the current one as it trundles North toward Northern Britain early in the week setting up a windy and unsettled week with rain and showers in cool and sometimes strong Westerly winds. All eyes then are on the chances of a pressure build from the South or SW making it in time to bring a change to fine and dry weather but in all honesty from what I can make out this morning improvements are likely to be too slow to give the UK anything other than an average Bank Holiday Weekend with the threat of at least some rain or showers still evident. Thereafter there are plenty of charts which do show a full blown improvement in the shape of High pressure crossing the UK giving fine and warm weather in early September but as has been the case all Summer the desire not to release the persistent trough over the Eastern Atlantic from some output is a worry with some output still showing only muted and half-hearted improvements resulting still changeable conditions across the UK in early September too. So while this weeks guaranteed wet end of Summer period unfolds we must hope that the model runs that show High pressure moving into the UK as we get into September have got a handle on things correctly and we can put to bed this rather poor Summer for the North and West but an OK one elsewhere if not a little disappointing for much of the time given the near continent has has an almost continual Summer of impressive heat and dry weather.

 

Next update from 09:00 Monday Aug 24th 2015

[knocker]

their is no agreement between the GEFS and ECM anomalies this morning although this is essentially a time line difference and not with the basic theme of pressure rises to the west. Basically the ECM is lagging the GEFS by 24 hrs in moving the upper trough east 00z Sunday thus the trough is still adjacent to the UK. Subsequently they both agree with building HP adjacent to the UK with the GEFS being more aggressive.

 

Essentially this would give reasonable weather, although the temps would be nothing to write home about, but having been down this route before caution prevails.

http://www.tropicaltidbits.com/

[johnholmes]

I think it looks fairly clear, at any rate to me, using my set of anomaly charts, that 6 days from now the upper air pattern will essentially be a westerly across the Atlantic.

[Singularity]

It will be interesting to see whether the pressure rise for the west in 8-10 days time is undone by low pressure development SW or S of the UK that lifts north, as we have seen a number of times this summer. I can see how this could be a consequence of an enhanced thermal gradient between what again looks to be a combination of an unusually hot NW Europe and anomalously cool mid-Atlantic.

 

In the meantime, tomorrow has the potential to deliver some high rainfall totals across Southern England, as a small area of low pressure, carrying some decent moisture amounts (but far from exceptional) interacts with cooler air to the NW. The high-res models offer a range of paths for the system and its rains, some only clipping The Southeast while others take precipitation as far northwest as Bristol. Good luck if you're forecasting for any outdoor activities!   

[ANYWEATHER]

Evening all ! The all important Bank Holiday Weather from a very unreliable time frame shows ecm bringing high pressure into the equation, gfs  shows otherwise  Take youre pick , cool and cloudy or warm and wet ,the choice is yours....  

Edited August 23, 2015 by ANYWEATHER

[I remember Atlantic 252]

Evening all ! The all important Bank Holiday Weather from a very unreliable time frame shows ecm bringing high pressure into the equation, gfs  shows otherwise  Take youre pick , cool and cloudy or warm and wet ,the choice is yours....  

 

cool and cloudy my choice

[knocker]

Interesting conundrum for the Bank Holiday. Taking the GFS ops first. It develops a low Biscay midnight Sunday brings it north and keeps it over the UK for four days.

 

What of the anomalies. Well at T144 there is a trough just to the west of the UK running a long way south which I suppose could support a scenario of activity in the Biscay area but the upper air pattern appears quite fluid and within 24 hours the trough is no  more  apart from a cut off low way south and heights are rising to the west.  This develops into a flattish westerly pattern. This would still indicate to me reasonable weather, if somewhat cool, for the latter part of the holiday

Charts weatherbell

[knocker]

The ECM also rapidly loses the trough and develops heights to our west. Maybe a surface analysis something like this. Hope springs eternal............

http://www.tropicaltidbits.com/analysis/models/?model=ecmwf-ens&region=nhem&pkg=mslpa_sd&runtime=2015082312&fh=192&xpos=0&ypos=342

Edited August 23, 2015 by knocker

[Captain Shortwave]

Evening all ! The all important Bank Holiday Weather from a very unreliable time frame shows ecm bringing high pressure into the equation, gfs  shows otherwise  Take youre pick , cool and cloudy or warm and wet ,the choice is yours....  

Or.....

Warm to hot and potentially dry

 

The GFS has the same idea, building a ridge towards southern Greenland yes, but at the same time allows downstream amplification with low pressure becoming trapped to the south west of the UK as heights rebuild over Europe, the UK under a increasingly warm south easterly flow.

 

The GFS has the same idea this morning.

 

Trough lifts out at the end of the week but leaves an area of low heights stuck to the south west of the UK setting up a potential plume event. The GFS gets the 20C isotherm up to the south coast. With the evolution at 5 days out, then there is a real possibility of another short pulse of true summer heat, with the associated chance of thunderstorms.