Model output discussion - hot spell beckons but then what?

[nick sussex]

Since the 00hrs run the GFS has expanded and edged the hottest 850s further west for Thursday.

 

[Captain Shortwave]

In reality the pattern isn't much different across the models at day 4, but the small differences between them could mean the difference between 32C and something pushing close to 100F if you can keep the flow coming from Central/Northern France.

GFS

   

Much slower in the progress of that secondary low with warm air wrapping around it. 

Arpege

   

The low takes a more northerly path with a curve similar to others, this seems to be akin to the ECM solution offered over the past few days.

UKMO

   

Probably the least hot of the solutions, but probably holding on in the eastern side of the country.

Further on, there seems to be a chance that the following Atlantic flow could get some modification as it struggles to clear the heat to the east, this could mean the temperatures hold in the mid twenties quite widely across the UK.

Edited July 21, 2019 by Captain Shortwave

[Djdazzle]

Hoping UKMO does the same!

[mb018538]

Looking increasingly like Thursday may be the hottest day before the Atlantic piles through Friday. Mid thirties(35-37c) on the cards if these charts verify.

[MattStoke]

Translates to 36’C in London. Add on the usual 2/3’C to that....

Edited July 21, 2019 by MattStoke

[Frosty.]

12 minutes ago, Mattwolves said:

The 2nd plume of heat hitting quite a large area come Thursday.... Now if sunshine amounts play ball, we could be about to see some records fall. 

It's looking more like two nice bites at the Apple / Cherry, 2 waves of heat..heat fans cups runneth over during the next 4 / 5 days!..and some big storms for some too!

Edited July 21, 2019 by Jon Snow

[Man With Beard]

The hottest GFS run we have (ever?) seen - and this is just D4:

Bearing in mind the usual underestimations, is 40C possible here? 

I would guess the UKMO 12Z is 2 or 3 degrees cooler at this time though. 

[MattStoke]

UKMO. Sizzling South East.

[shaky]

3 minutes ago, Man With Beard said:

The hottest GFS run we have (ever?) seen - and this is just D4:

Bearing in mind the usual underestimations, is 40C possible here? 

I would guess the UKMO 12Z is 2 or 3 degrees cooler at this time though. 

Ukmo very slightly cooler but still very hot!!if you ask me i would go with gfs at 72 and 96 hours over the ukmo any day!!also if the ecm shows the same thing as gfs this evening then we can pretty much be confident of a potential record breaking day on thursday!!one things for certain the theme throughout today is to push the heat further and further west with each run today and we could have a full house this evening!!

[Mike Poole]

4 minutes ago, Man With Beard said:

The hottest GFS run we have (ever?) seen - and this is just D4:

Bearing in mind the usual underestimations, is 40C possible here? 

I would guess the UKMO 12Z is 2 or 3 degrees cooler at this time though. 

Yes, this is interesting , compare my post on the 6z, here now we have higher peak temperatures and also modelled less cloud cover - so many things to watch to form a view on how high the temperature could get.   GFS temps and cloud at T102:

[Mapantz]

If you want to just chat about the upcoming hot spell, can you please do it over here:

 

Thanks! 

[knocker]

One can certainly see the potential for storms Tues/Weds looking at the potential medium level instability

[Man With Beard]

1 minute ago, NTC said:

Of course it is I mean how many people predicted 40 plus in June from the models when it got nowhere near.they always over egg it its what gives Nathan Rao his material everyday exaggerated charts

Different situation this time. The models unanimously did not predict record breaking temps within D6 in June. This time, they are all predicting something close to the record and it's now D4. 

[MattStoke]

1 minute ago, Djdazzle said:

Very different setup this time though.

It’s also only at day 4 rather than a couple of model runs for over a week away like last time. GFS often has temperatures a few degrees too low in such setups.

[nick sussex]

The wind direction looks perfect for many of the normal hot spots . It’s really down to sunshine amounts .

Shame about the UKMO , if that would have been on board you could get close to some records .

[Captain Shortwave]

Arpege trickling out the temperature predictions now

Monday

30C across East Anglia and Lincolnshire possible thanks to a west of south wind direction.

Tuesday

34C across favored locations in central/southern England, possibly 35C.

Wednesday

32C across East Anglia, but temperatures look difficult to pin down as we see elevated showers/thunderstorms moving NNE during the morning, so cloud cover will be a variable to consider. Worth noting that Tuesday night will be a very warm and humid, lows of 22C in the south east.

Edited July 21, 2019 by Captain Shortwave

[Methuselah]

Looks a tad delayed, to me...is that a small patch of 20C upper over the Moray Firth?

   

If it's going to happen, I'm thinking Thursday will be the day?

[Singularity]

Parched soils across France will also be a factor.  The models tend to underestimate the amount of solar energy this frees up for heating as opposed to evaporation of soil moisture.

I suppose we also have pretty dry soils across much of S UK now too, even after the Fri-Sat rain as much of that will have been guzzled by thirsty plants or quickly percolated down beneath the surface layers.

Theres a lot of ingredients coming together.  Shame for anyone chasing local records across central parts that the small disturbance moving through on Tue night introduces a little fresher Atlantic air for a time on Wed; this really cuts down the day-on-day heat build. Eastern parts look to escape that.

Models still vary on the timing and strength of that circulation, mind. The ECM 00z made hardly anything of it, leaving central parts hotter on Wed and hence allowing them to become so on Thu too (and the 12z FV3 has moved quite close to this outcome).

Edited July 21, 2019 by Singularity

[kold weather]

Stronger agreement on Weds and Thurs now from models, most going into the 34-36 range. Plenty of time yet for changes but looking like staying hot in the SE till Friday.

[nick sussex]

2 minutes ago, I remember Atlantic 252 said:

Aye 41 degrees or so modeled

I’m thinking more for the UK .

Areas like Gravesend with the sandy soil . Here in France I don’t think we’ll beat the record from last month .

Its possible if everything aligns the UK record could go but it’s crucial to miss any possible storms Tue into Wed .

Certainly though the UKMO needs to correct west though for that to be achieved.

[Mike Poole]

GEM with a substantial chunk of the country under +20 uppers at just T96:

I'm edging up the UK temperature record going probability to 22%...

[clark3r]

I’m starting to wonder if the breakdown will be delayed even further over the next few days 

[Frosty.]

For anyone dreading the intense heat and humidity during much of the week ahead, there is salvation from the ukmo 12h with a transition to cooler on friday, fully completed by saturday (T+144 hours)

Edited July 21, 2019 by Jon Snow

[Captain Shortwave]

Arpege day 4 - Thursday

36C - Good chance of the July record and local all time records going.

[Derecho]

18 minutes ago, knocker said:

One can certainly see the potential for storms Tues/Weds looking at the potential medium level instability

Is this what the skew chart shows knocker?

Seems to be a lot of instability there...

Edited July 21, 2019 by Quicksilver1989