Model output discussion - hot spell beckons but then what?

[knocker]

2 minutes ago, kold weather said:

Still hot, but noticeably cooler than some of the other models out there tonught.

Seems to stem from the overnight mins dropping away quite nicely. For example, London down to 17c by 1am...

Looks somewhat too low to me though based on what all the other models are showing...

I think the problem may well be some medium cloud vis unstable air

[kold weather]

ECM 12z has a max of 35-36c in London on Thursday, still very hot for sure but the much cooler overnight temperatures compared to the 00z is what stops any record attempt.

Also worth noting the other difference is the heat concentration looks a little more widespread than on the 00z.

knocker - I think the main difference is purely those night time temps, the 00z had 66f at 2am over London (which is about the lowest it goes, it rises from that point) whilst the 12z ECM has 62-63f. That 3-4f difference makes the difference from the 96f of this run, and the 100f of the previous run. Simple as that from what I can see.

Edited July 22, 2019 by kold weather

[Derecho]

6 minutes ago, kold weather said:

Still hot, but noticeably cooler than some of the other models out there tonught.

Seems to stem from the overnight mins dropping away quite nicely. For example, London down to 17c by 1am...

Looks somewhat too low to me though based on what all the other models are showing...almost certainly the coolest of the main models for sure tonight...

The key is the wind direction, at the surface the ECM for midday Thursday has ESE winds over the SE UK... whilst on the GFS they are from the SSE.

As a result the GFS is a few degrees warmer over SE England. Either that or more cloud cover on the ECM.

Edited July 22, 2019 by Quicksilver1989

[MattStoke]

Highest temperature on the ECM is 36’C over North Kent. 2 degrees lower than previous updates.

[Met.]

GFS I looked at shows up to 35 as well which seems more realistic.

Edited July 22, 2019 by Thundershine

[Frosty.]

Compared to what the models were showing a few days ago, if you're a heat fan these upgrades today are sensational, the Ecm 12z operational still looks hot across the east on friday..as for thursday..gonna be hot, hot, hot..smokin!!!!

Edited July 22, 2019 by Jon Snow

[MATTWOLVES 3]

The ECM op is a very warm run throughout, we even have serious heights over scandy.... Could at long last we be starring down the barrel of a very encouraging August. 

Edited July 22, 2019 by Mattwolves

[kold weather]

1 minute ago, Quicksilver1989 said:

The key is the wind direction, at the surface the ECM for midday Thursday has ESE winds over the SE UK... whilst on the GFS they are from the SSE.

As a result the GFS is a few degrees warmer over SE England. Either that or more cloud cover on the ECM.

Yeah that seems the route cause, though its very much the night time temps that are the limiter as explained above (IE, we get the same level of increase in temperatures, just we start from a 1-2c lower base to start with, so we end up 1-2c lower).

[MattStoke]

2 minutes ago, Thundershine said:

GFS I looked at shows up to 35 as well which seems more realistic.

35’C is low for this setup.

Edited July 22, 2019 by MattStoke

[knocker]

The ecm merges the Atlantic and European troughs which poses the interesting possibility of a repeat watered down version

Edited July 22, 2019 by knocker

[Singularity]

   

Well hello there... bit of a messy split away of LP to slide SE but it gets there on Monday and the Scandinavian high is notable in its persistence.

All that hot air aloft, descending as it slowly cools, may help the anticyclone to persist longer than might otherwise be expected.

Variably across the days Sat-Thu, this run keeps eastern parts within 100-400 miles of an extended severe heatwave. Sounds like a lot until you think on the global scale that these models operate on.

Definitely a trend to keep an eye on. Really interesting how this is starting to look a bit more like what the hottest model runs of 3-4 days ago were depicting to unfold as a result of tomorrow's LP out west splitting in two and dropping a cut-off low west of Iberia. Different routes to a similar end result - albeit probably a fair bit less extreme (remember that GFS 06z continuing mid-30s maximums right through the weekend for S. England? Hottest 10-day period of a model run that I've ever seen for this locality, full stop).

[Man With Beard]

Tonight's big picture story from the ECM is... the Scandi block wins!! Warm throughout the run, if it isn't thundering! 

36C or 38C?... that's looking too closely at the charts imo. The models are bound to play within a range, but won't be settled until the very day for sure! Actually, there may be more chance of a record on this run as there's a 36C slap over London (raw temps, usually add a bit to that), and so more likely for the heat to coincide with a met office station e.g. Heathrow. 

[kold weather]

2 minutes ago, MattStoke said:

35’C is low for this setup.

I have to admit its lower than what I'd expect with the profile as it is, however we saw a few weeks ago that the surface conditions don't always reflect the crazy set-up above it.

Besides, for perspective, the 36c the ECM has has only been beaten a handful of times, its still a really exceptional shot of heat by any standards.

[MattStoke]

1 minute ago, kold weather said:

I have to admit its lower than what I'd expect with the profile as it is, however we saw a few weeks ago that the surface conditions don't always reflect the crazy set-up above it.

Besides, for perspective, the 36c the ECM has has only been beaten a handful of times, its still a really exceptional shot of heat by any standards.

That’s because a few weeks ago we had the surface flow coming over the North Sea. This time we have the wind coming from a record breakingly hot Northern France and over the shortest and warmest sea track. Seen 35’C reached in far less favourable setups than this one. 35’C as the highest temperature from this would be very low!

[nick sussex]

6 minutes ago, kold weather said:

ECM 12z has a max of 35-36c in London on Thursday, still very hot for sure but the much cooler overnight temperatures compared to the 00z is what stops any record attempt.

Also worth noting the other difference is the heat concentration looks a little more widespread than on the 00z.

knocker - I think the main difference is purely those night time temps, the 00z had 66f at 2am over London (which is about the lowest it goes, it rises from that point) whilst the 12z ECM has 62-63f. That 3-4f difference makes the difference from the 96f of this run, and the 100f of the previous run. Simple as that from what I can see.

Maybe the 00 hrs was projecting cloud cover and hence the higher overnight temps . I really wouldn’t be too concerned re these slight changes , overall the models have expanded the heat on Thursday .

The high 850s haven’t been shunted east so I still think the record has a chance of being broken .

[knocker]

Average temps over the weekend according to the ecm

 

[Frosty.]

Does it really matter if it's 36c instead of 38c?..most of the uk is going to be lower than that anyway!!!. I'm just delighted with the westward corrections prolonging the hot spell!!

[kold weather]

6 minutes ago, nick sussex said:

Maybe the 00 hrs was projecting cloud cover and hence the higher overnight temps . I really wouldn’t be too concerned re these slight changes , overall the models have expanded the heat on Thursday .

The high 850s haven’t been shunted east so I still think the record has a chance of being broken .

For sure, as Man with Beard correctly said, we are still well within the ballpark of both the July and all time record even if the ECM 12z is correct with the cooler temperatures overnight, as there are several well placed stations that could pick up the heat on that run better than if it was shunted east of London.

Personally, I'm happy with the 12z ECM, in my area it actually is an upgrade in temperatures, though still doesn't appear quite as high as it was on the June heatwave (as we were not far from the main heat zone on that one).

Quite a bland weekend temperature wise, cooler than the 12z GFS for example (temps seem widely 21-23C, so fairly average).

Indeed VERY wet weekend for East Anglia on this run, 25-30mm of rain!

Edited July 22, 2019 by kold weather

[Singularity]

13 minutes ago, Quicksilver1989 said:

The key is the wind direction, at the surface the ECM for midday Thursday has ESE winds over the SE UK... whilst on the GFS they are from the SSE.

As a result the GFS is a few degrees warmer over SE England. Either that or more cloud cover on the ECM.

Good observation.

I was warning of this possibility this morning, should the westward corrections continue... as they have done.

A wider area sees very hot maximums, but the very highest temp may be lower due to the optimal timing of surface flow occurring west of the most urbanised region.

Even so, with 35*C on the raw ECM, and typical error factored in, that July record remains strongly under threat.

 

Now for another angle on affairs:

That might well be the most extreme cross-polar ridge I've ever seen in July. Extraordinary.

[Met4Cast]

Question.. this is the UKV from the 15z run for 3pm on Thursday. One is with sea mask & the other is without

Why are they showing different temperatures? Same run, same timeframe.

[MATTWOLVES 3]

7 minutes ago, knocker said:

Average temps over the weekend according to the ecm

 

According to the op it stays very warm... 

[Mapantz]

Something to keep an eye on for Thursday.. UKV suggest showers/thunderstorms moving in to the Southeast. If that comes to fruition and comes in slightly earlier, it may affect max temps.

 

[kold weather]

1 minute ago, Mattwolves said:

According to the op it stays very warm... 

It cools down quite considerable amount to average for the weekend (indeed its a AWFUL weekend for E.A, with 1 inch of rain and temperatures of about 16-19C) but once that eases off and we get back into the weak ridging, things warm up nicely again to between 24-28c, so more than good enough and probably wouldn't be going anywhere fast either.

Decent area of 32C+ on the ECM this run for Thursday, even if the peak heat is a little more stunted.

[nick sussex]

2 minutes ago, Mapantz said:

Something to keep an eye on for Thursday.. UKV suggest showers/thunderstorms moving in to the Southeast. If that comes to fruition and comes in slightly earlier, it may affect max temps.

 

Not sure where it’s getting those storms from , it has them coming out of northern France . Meteo France have it dry , for that region.

[Derecho]

10 minutes ago, Singularity said:

Good observation.

I was warning of this possibility this morning, should the westward corrections continue... as they have done.

A wider area sees very hot maximums, but the very highest temp may be lower due to the optimal timing of surface flow occurring west of the most urbanised region.

Even so, with 35*C on the raw ECM, and typical error factored in, that July record remains strongly under threat.

 

Now for another angle on affairs:

That might well be the most extreme cross-polar ridge I've ever seen in July. Extraordinary.

Yup the ECM has a SSE flow when looking at the pressure charts. However pressure charts show geostrophic winds (free of fricttion) whilst surface winds are usually at a 25 degree angle anti-clockwise.

So over SE England we get a flow from Belgium / Netherlands to the ESE which is modified more by the North Sea. The GFS taps straight into that hot air over Paris and with little modification from the channel the temperature charts as a result show 38C over London.

A little difference can be what determines whether a record is broken or not. The trade off is that more areas on Thursday get above 30C.

ECM also pushes the hot air into the North Sea quicker on Friday compared to GFS, will be interesting to see where it sits in the ensembles....

Will the ECM ensemble fall in line with the GFS ensembles and keep the heat till saturday? Or will it follow the OP?

Despite the OP some warmth still manages to come back later after some more average temperatures further south this weekend.

Edited July 22, 2019 by Quicksilver1989