Model Output Discussion 22/07/12 Onwards.

[Robbie Garrett]

Just had a brief look at the Charts, August might be pretty good. Quite a few warm spells, and September may be the Summer month we've all been waiting for..... September in my eyes never fails to shine!!

[Alex]

Just had a brief look at the Charts, August might be pretty good. Quite a few warm spells, and September may be the Summer month we've all been waiting for..... September in my eyes never fails to shine!!

September never fails to shine? 2010,2009,2008 & 2007 weren't brilliant! 2006 and 2011 are the only decent months I can think of in recent times unless you are relating to something different to warm dry sunny months, saying that most septembers do include a period of anticyclonic weather more so sometimes than summer months.

[damianslaw]

Reliable timeframe - heights are going to build over the mid atlantic and we are going to pull down a cool northerly airstream behind a cold front come Friday. The weekend will see temps down to average levels in the south, and below average in the north.

Into next week - its a cool showery outlook to start before a low pressure tracks across the north of the country bringing heavy rain to northern parts and maintaining the rather cool feel.

Later next week, signs of the azores high once again trying to ridge NE, but, I think there will be quite some oomph in the atlantic and any quick return to the conditions of now look quite slim, with only the very far south/south east having any real chance of seeing a return of sunny very warm weather. Its a typical August pattern, with the wettest coolest cloudiest weather reserved for the NW. August is traditionally when the atlantic begins to stir into second/third gear and is much more likely to dominate proceedings compared to any month since January.. it does well to remember Feb on average sees a much quieter atlantic than August.. we are now entering the wetter half of the year (Aug - Jan).

[Staffordshire]

Just wondering what would an azores high would do for canaries + west Africa?

[shedhead]

One word for this chart.....horrendous!

No easy way back to fine, dry and warm IF this were to verify, indeed I think we could pretty confidently write off the first third of Aug. Once again we appear to be staring down the barrrel and just when you think things can't possibly start to look any worse, they do!

Edited July 25, 2012 by shedhead

[SP1986]

I agree Shedhead, it does appear that the air will come from a northerly quadrant for quite some time.. in fact basing on these runs, at least the first half of August could be written off (in theory).

I'm not sure whether that will bring showery weather or plain old cloud and rain, but it could turn very very wet once again with the potential for further flooding from heavy showers or persistent rainfall. Certainly a dire outlook by the models right now.. but this is become a very familiar pattern this summer, and we should probably get used to it.

[Cheshire Freeze]

In FI I know at 4854 hrs out but IMO this is nailed...........

Sorry mods, just a bit of banter!

Edited July 26, 2012 by CreweCold

[Snowy Easterly]

best northerly in history too bad its just fantasy

[Cheshire Freeze]

best northerly in history too bad its just fantasy

ha the run just changed to show a sw'ly for the same time frame....had to edit the post quickly so that people didn't think I'd gone mad

[William of Walworth]

What the hell happened to that GFS FI-candy (for around 8 August) that Summer Sun was posting as recently as yesterday?

I don't get such a violent switch now, leading one or two people above overconfidently (IMO), and on just this latest admittedly worrying-looking set of runs, to write off a third (!!??) of August already.

It's not even 1st August yet!

I'm reluctant to credit such a comprehensive write off of such a big chunk of a month on what after all is ONE set of runs!!

Apply more caution I'd advise, and don't over-interpret yet -- FI operationals can over ramp HP influence sure, but the same can be true in reverse, very possible that these rainy deep lows for later on are being overcooked too.

Edited July 26, 2012 by William of Walworth

[ANYWEATHER]

Looks like a convergence zone later today over the midlands and central parts of England. Scope for some heavy showers or thunderstorms around this area. Then starting to turn insettled for all by the weekend and much cooler with showers and into next week rain, showers and cooler conditions for all.Looks as though there could well be some heavy showers too for SE England tomorrow night!

[sebastiaan1973]

The first -10 at 850hpa of the season?

[Glacier Point]

Been talking of late about the potential for the ridge in the Atlantic to withdraw westwards (and corresponding shift westwards of our mean trough) during week 2 of August giving something of a topsy turvy weather pattern - hot, cool and unsettled...warm, becoming hot once again ?

With increasing tropical convection forecasts indicating a likely rise in angular momentum, the 'non' model inference is for troughing to establish in the Atlantic.

Secondly, from CPC last night..

THE GFS-BASED SOLUTIONS, INCLUDING THE GFS SUPER-ENSEMBLE MEAN,

INDICATE A SLIGHT WESTWARD SHIFT OF THE PATTERN JUST AS THEY DID YESTERDAY. IF

CORRECT, THIS SUGGESTS A WETTER PATTERN FOR THE ATLANTIC COAST STATES, AND A

WESTWARD SHIFT OF MONSOON MOISTURE INTO WESTERN PORTIONS OF THE SOUTHERN

PLATEAU REGION.....

THE 8-14 DAY SURFACE TEMPERATURE AND RAINFALL OUTLOOKS ARE SIMILAR TO THOSE

PREDICTED FOR THE 6-10 DAY PERIOD, WITH RELATIVELY MINOR ADJUSTMENTS. THE

GFS-BASED RUNS ARE ANTICIPATING A SLIGHT RETROGRESSION OF THE FLOW PATTERN OVER

THE CONUS, WHICH SUGGESTS MONSOONAL MOISTURE MAY SHIFT WESTWARD AS WELL FROM

NEW MEXICO AND EASTERN ARIZONA TO WESTERN ARIZONA AND SOUTHERN NEVADA.

And thirdly, GEFS 500mb mean height anomaly for t300 onwards starts to really develop this pattern. Note the troughing signal in the Atlantic.

Definately a trend to watch here.

[shedhead]

What the hell happened to that GFS FI-candy (for around 8 August) that Summer Sun was posting as recently as yesterday?

I don't get such a violent switch now, leading one or two people above overconfidently (IMO), and on just this latest admittedly worrying-looking set of runs, to write off a third (!!??) of August already.

It's not even 1st August yet!

I'm reluctant to credit such a comprehensive write off of such a big chunk of a month on what after all is ONE set of runs!!

Apply more caution I'd advise, and don't over-interpret yet -- FI operationals can over ramp HP influence sure, but the same can be true in reverse, very possible that these rainy deep lows for later on are being overcooked too.

No one has confidently written off the first third of Aug, which had you read my post properly you would have concluded.

Posted Yesterday, 22:36

One word for this chart.....horrendous!

No easy way back to fine, dry and warm IF this were to verify, indeed I think we could pretty confidently write off the first third of Aug. Once again we appear to be staring down the barrrel and just when you think things can't possibly start to look any worse, they do!

[NorthNorfolkWeather]

Been talking of late about the potential for the ridge in the Atlantic to withdraw westwards (and corresponding shift westwards of our mean trough) during week 2 of August giving something of a topsy turvy weather pattern - hot, cool and unsettled...warm, becoming hot once again ?

With increasing tropical convection forecasts indicating a likely rise in angular momentum, the 'non' model inference is for troughing to establish in the Atlantic.

Secondly, from CPC last night..

THE GFS-BASED SOLUTIONS, INCLUDING THE GFS SUPER-ENSEMBLE MEAN,

INDICATE A SLIGHT WESTWARD SHIFT OF THE PATTERN JUST AS THEY DID YESTERDAY. IF

CORRECT, THIS SUGGESTS A WETTER PATTERN FOR THE ATLANTIC COAST STATES, AND A

WESTWARD SHIFT OF MONSOON MOISTURE INTO WESTERN PORTIONS OF THE SOUTHERN

PLATEAU REGION.....

THE 8-14 DAY SURFACE TEMPERATURE AND RAINFALL OUTLOOKS ARE SIMILAR TO THOSE

PREDICTED FOR THE 6-10 DAY PERIOD, WITH RELATIVELY MINOR ADJUSTMENTS. THE

GFS-BASED RUNS ARE ANTICIPATING A SLIGHT RETROGRESSION OF THE FLOW PATTERN OVER

THE CONUS, WHICH SUGGESTS MONSOONAL MOISTURE MAY SHIFT WESTWARD AS WELL FROM

NEW MEXICO AND EASTERN ARIZONA TO WESTERN ARIZONA AND SOUTHERN NEVADA.

And thirdly, GEFS 500mb mean height anomaly for t300 onwards starts to really develop this pattern. Note the troughing signal in the Atlantic.

Definately a trend to watch here.

Hi GP,

Just a quick question, how common is such a retrogression given the time of year?

[snowmadchrisuk]

Doesn't look to bad as things stand , Nothing like the last 3 Months anyway. 850's rising to around +10 again 1st-3rd August , All Ensembles agree and after that some go Hot some go Cold, Looks like a perfect Winter Patten may set up over Greenland, shame its the middle of Summer

[Backtrack]

One word for this chart.....horrendous!

No easy way back to fine, dry and warm IF this were to verify, indeed I think we could pretty confidently write off the first third of Aug. Once again we appear to be staring down the barrrel and just when you think things can't possibly start to look any worse, they do!

Actually Shed, I think there is quite an easy route back this time, and this troughing pattern will not last very long at all. My current thoughts are that August will be the best summer month, and possibly the best August for some time away from the first 8-10 days.

Edited July 26, 2012 by Backtrack

[johnholmes]

Actually Shed, I think there is quite an easy route back this time, and this troughing pattern will not last very long at all. My current thoughts are that August will be the best summer month, and possibly the best August for some time away from the first 8-10 days.

good news I'm sure for most on here Backtrack but how about showing us some information on why you can post such optimism or is it just a gut feeling you have?

[Scorcher]

No easy way back to fine, dry and warm IF this were to verify, indeed I think we could pretty confidently write off the first third of Aug. Once again we appear to be staring down the barrrel and just when you think things can't possibly start to look any worse, they do!

Things could look a lot worse actually, remember June?

[Robbie Garrett]

September never fails to shine? 2010,2009,2008 & 2007 weren't brilliant! 2006 and 2011 are the only decent months I can think of in recent times unless you are relating to something different to warm dry sunny months, saying that most septembers do include a period of anticyclonic weather more so sometimes than summer months.

Been talking of late about the potential for the ridge in the Atlantic to withdraw westwards (and corresponding shift westwards of our mean trough) during week 2 of August giving something of a topsy turvy weather pattern - hot, cool and unsettled...warm, becoming hot once again ?

With increasing tropical convection forecasts indicating a likely rise in angular momentum, the 'non' model inference is for troughing to establish in the Atlantic.

Secondly, from CPC last night..

THE GFS-BASED SOLUTIONS, INCLUDING THE GFS SUPER-ENSEMBLE MEAN,

INDICATE A SLIGHT WESTWARD SHIFT OF THE PATTERN JUST AS THEY DID YESTERDAY. IF

CORRECT, THIS SUGGESTS A WETTER PATTERN FOR THE ATLANTIC COAST STATES, AND A

WESTWARD SHIFT OF MONSOON MOISTURE INTO WESTERN PORTIONS OF THE SOUTHERN

PLATEAU REGION.....

THE 8-14 DAY SURFACE TEMPERATURE AND RAINFALL OUTLOOKS ARE SIMILAR TO THOSE

PREDICTED FOR THE 6-10 DAY PERIOD, WITH RELATIVELY MINOR ADJUSTMENTS. THE

GFS-BASED RUNS ARE ANTICIPATING A SLIGHT RETROGRESSION OF THE FLOW PATTERN OVER

THE CONUS, WHICH SUGGESTS MONSOONAL MOISTURE MAY SHIFT WESTWARD AS WELL FROM

NEW MEXICO AND EASTERN ARIZONA TO WESTERN ARIZONA AND SOUTHERN NEVADA.

And thirdly, GEFS 500mb mean height anomaly for t300 onwards starts to really develop this pattern. Note the troughing signal in the Atlantic.

Definately a trend to watch here.

Something worth keeping an eye on, we will get one decent Summery spell. Not forgetting we are having one now. A week of 28-30*C down South is considered a decent Summery spell if it's longer than one or two days. September has always been a decent month for me for the last few years, I have flown quite a bit during that month (2010, 2011).

Will be a shame to see August go down the gutter AGAIN, but I suspect August may have one or two warm spells, unless the weather keeps the same vain - unsettled 2/3rd and then settled final 1/3rd.

Edited July 26, 2012 by Robbie Garrett

[Backtrack]

good news I'm sure for most on here Backtrack but how about showing us some information on why you can post such optimism or is it just a gut feeling you have?

With the Azores high retrogressing further westward into the Atlantic it allows the trough room to move with it, allowing height rises to the east, a pattern which I believe will become a lock and reload scenario throughout August.

[shedhead]

Actually Shed, I think there is quite an easy route back this time, and this troughing pattern will not last very long at all. My current thoughts are that August will be the best summer month, and possibly the best August for some time away from the first 8-10 days.

Again Backtrack I will refer you to what my post actually said... IF that chart I posted for 2nd Aug verifed, there would be no easy way back.

[johnholmes]

With the Azores high retrogressing further westward into the Atlantic it allows the trough room to move with it, allowing height rises to the east, a pattern which I believe will become a lock and reload scenario throughout August.

I think most would hope you are correct.

Its a possibility but at the moment I would rate it as a probability of 20% perhaps 30%

[shedhead]

I think most would hope you are correct.

Its a possibility but at the moment I would rate it as a probability of 20% perhaps 30%

Very much agree JH, 20-30% looks about right, maybe even a tad generous. I think that will be the eventual evolution, but we will be waiting well into week 2 of Aug for it to happen imo. In the short to medium term there's no way of making a silk purse out of a sows ear, it's downhill all the way next week and although not as bad as June it most certainly ain't looking pretty.

[Cloud 10]

Very much an unsettled outlook in the medium term with the now familiar pattern of high pressure to the west/north-west

and a sluggish trough over or near the UK,so showers or longer spells of rain would seem the order of the day.

Climate Prediction Center - 8-14 Day 500mb Outlook