Model output discussion - hot spell beckons but then what?

[Mapantz]

The UKV is showing a lot of cloud moving in on Wednesday afternoon, and showing it cloudy for much of the British Isles on Thursday. A long way off, but it may be one of those situations that puts pay to excessive temperatures, again.

[Summer Sun]

4 minutes ago, Mapantz said:

The UKV is showing a lot of cloud moving in on Wednesday afternoon, and showing it cloudy for much of the British Isles on Thursday. A long way off, but it may be one of those situations that puts pay to excessive temperatures, again.

Could be a few isolated storms breaking out during Wednesday afternoon too

[Mike Poole]

Interesting output once again this afternoon, one thing that is becoming certain is that if any records are to be broken it will be in the SE only! the highest uppers affects other areas only passingly on most models.  ECM mean T144:

Looks like a knight from one of those giant chess sets!  But if that's the mean then there will be members that stoke the furnace for quite a while.  And the op looked toasty for this area too.  Other models less so...

UK temperature record breaking probability?  I'm now at 13%.

[Sweatyman]

13 minutes ago, Mapantz said:

The UKV is showing a lot of cloud moving in on Wednesday afternoon, and showing it cloudy for much of the British Isles on Thursday. A long way off, but it may be one of those situations that puts pay to excessive temperatures, again.

This island really is the pits for getting anything noteworthy. Cloud magnet 

[swanseajack23]

Looking really disappointing for us here in SW Wales. Wasn’t expecting much but one day of 26/27 degrees on Tuesday , with cloud, cloud and more cloud either side of that meh! 

[Djdazzle]

I wouldn’t bet on it being that cloudy, especially further East.

[MATTWOLVES 3]

In my experience guys when they say plenty of sunny spells, expect the opposite... And I would imagine that works the other way round to! I'm still seeing largely sunny skies on Tuesday... Wednesday the same, but with an increasing risk of thundery showers later... Wouldn't get to hung up about it anyway... Because by the end of the week we are back in more typical conditions.... Let the hunt for plume 3 commence.... This time one with balls....

[Kentspur]

11 minutes ago, swanseajack23 said:

Looking really disappointing for us here in SW Wales. Wasn’t expecting much but one day of 26/27 degrees on Tuesday , with cloud, cloud and more cloud either side of that meh! 

Can we swap locations for the week I have to drive from kent throughout London and heathrow in a non air con van all day!

[Spurry]

Looks like the HP is going to be situating itself over Scandinavia and drawing in some warm air from the continent ,which bodes well for me as I'm off to W Sweden tomorrow for a week with the wife.

[Djdazzle]

GFS 18z seems to increase the chances of a very hot Thursday. LP less influential and more elongated, allowing a better feed off the continent.

[ancientsolar]

looks like GFS 18:00 has the LP moved westwards a touch, 
wide spread 30C over Southern UK Thursday ?

[Singularity]

3 minutes ago, Djdazzle said:

GFS 18z seems to increase the chances of a very hot Thursday. LP less influential and more elongated, allowing a better feed off the continent.

Yes this raises my eyebrows - some of that stretching I mentioned to look out for earlier. Does enough that despite the heat being a little more east on Wed it shifts back NW on Thu via a surface flow from France.

Also another low swinging into the trough complex on Thu - who’s up for another round of ‘hold back that trough’? 

Edited July 20, 2019 by Singularity

[Man With Beard]

GFS 18Z quite similar to ECM 12Z for next Thursday 

Also interesting to see possible wrap around of heat for northern parts on Friday? (nearly but not quite) 

[Djdazzle]

It’s getting quite interesting now in terms of the potential for extreme heat. If the 00z runs continue the westward adjustments then I feel 100F will be reached, particularly as Paris is being forecasted to reach 41C. And we have a direct feed from France.

[ancientsolar]

4 minutes ago, Djdazzle said:

It’s getting quite interesting now in terms of the potential for extreme heat. If the 00z runs continue the westward adjustments then I feel 100F will be reached, particularly as Paris is being forecasted to reach 41C. And we have a direct feed from France.

yes , some of these temperatures look like they'll stay above 20C Wednesday night.. and late 20's by 9am Thursday .. it could be a close one, 
I suppose it really depends on how aggressive the jet stream is, but it's really weak and struggling.. that LP that's suppose to his us.. could just get weaker.. people here said it was often over cooked on GFS as it was.. 
then again.. the record potential could be shut down by thunderstorms. It's hugely interesting to see the charts unveiled. 

 

[knocker]

Outlook - A fairly rapid pattern transition over the next few days as a major upper trough drops into the Atlantic

The North Atlantic 500mb and surface analysis for midnight

Today will dawn clear in most areas of England and Wales and eastern Scotland and this will remain the case for most for the rest of the day with it getting quite warm in the south east where the odd shower may bubble up. But more cloud in western areas and and rain and strengthening winds from the frontal system which is tracking rapidly north east will be into N. Ireland by 0900 and this will spread north east also during the day affecting all areas north of a line north of N. Wales > Humber. This rain will be heavy at times.

The moderate rain will continue to effect the north through this evening and overnight as the triple point whips across central Scotland, particularly NW England and western Scotland. whilst further south it will be dry and quite warm.

Rain and strong winds will continue to effect western Scotland through Monday but the aforementioned change is under way and amplification is resulting in the movement of warmer air north and thus quite a marked NW/SE temp differential

Over Monday night and trough Tuesday the pattern continues to develop and it perhaps should be noted here our old trough breaking off to the north east which initiates a conduit to to a trough and upper low that develops in south east Europe which has a role to play shortly Meanwhile becoming increasingly warm, sunny and humid over all areas apart from the far north west of Scotland

The pattern over the next couple of days gets very complex and I'm not even going to attempt the detail. In a nutshell the upper trough to the west becomes negatively tilted and intensifies in the southern quadrant  as the burgeoning subtropical high, and hot air, is forced slowly east. This is where the trough/conduit in eastern Europe comes into play

Thus on Wednesday there is a surface low to the west of Ireland and a weak cold front attempting to cross the country. A very hot day with temps possible around the mid 30s in some southern areas. By Thursday this low has been joined by another tracking up from the south west (courtesy of the upper trough) and a more active cold front is crossing the country. Thus still a hot day in eastern regions but there is an increasing risk of thunder storms.as cooler air spreads from the west and increasing instability as the very warm air rises through the cooler air,

 

Edited July 21, 2019 by knocker

[knocker]

I don't think there is much point in looking too far ahead from here so suffice it to say by T144 the European ridge is being forced north west into Greenland courtesy of the negatively tilted trough lying across the UK and the Upper low and trough in southeast Europe

[Guest]

Seems like both GFS / UKMO are pretty closely tied at 96hrs in sweeping through the heat Wednesday night for most leaving just the extreme south east warm on Thursday - both have really quite unsettled fridays with a sub 995mb low centred just on the western coast of Ireland. ECM at 96hrs just a touch further west, maybe by 50/75miles. By day 6 UKMO looks to develop another secondary low whereas GFS lifts low pressure allowing for pressure to rise again from the south.

There just appears to be so much detail that needs to be resolved Tuesday evening onwards. Hints that there could be rounds of evening and overnight storms both Tuesday and Wednesday, quite often in these situations debris left over from the first rounds affects the following days events etc....

[Djdazzle]

Again LP being overdone by the models. Very unlikely to be that deep or intense. This will go to the wire. 

[Man With Beard]

5 minutes ago, Djdazzle said:

Again LP being overdone by the models. Very unlikely to be that deep or intense. This will go to the wire. 

With regard to the record breaking potential, I think you are right. These LPs can get downgraded even in the last 48 hours. 

However the general pattern for the week now seems nailed on - hotter and hotter Monday through Wednesday, heat becoming limited to the SE on Thursday and disappearing altogether through Friday. 

Thunderstorms / level of heat tbc! 

[knocker]

12 minutes ago, Djdazzle said:

Again LP being overdone by the models. Very unlikely to be that deep or intense. This will go to the wire. 

The gfs is very similar to the fax chart for midday Thursday so I'm interested in the reasons why you apparently disagree with Exeter? And as it happens the ecm does as well so all models is a bit sweeping

Whether they will be downgraded is above my pay grade

 

Edited July 21, 2019 by knocker

[Djdazzle]

1 minute ago, knocker said:

As the gfs is very similar to the fax chart for midday Thursday so I'm interested in the reasons why you apparently disagree with Exeter? And as it happens the ecm does as well so all models is a bit sweeping

 

It just seems to be a bit too clean and quick. Past experience also suggests that these developing LP’s get overblown.

[Porto]

Wed/Thurs temps on the Euro around the same before, 34c/35c ish which could mean up to 36c/37c locally, maybe higher but it really depends on cloud cover and how quickly that low moves in.

Edited July 21, 2019 by Loifeless

[knocker]

Latest wrf vis the last day of the Open

[Polar Maritime]

37c showing this morning for the S/E on the NetWx-mr for Thursday.