Model Output Discussion - 1st June 2015 12z--------->

[Methuselah]

And the GFS 06Z is looking like a stonker!

[Summer Sun]

GFS 06z is rising the heat touching 33c 91.4F in the south and close to 30c in the north east and North west of England

 

 

GFS certainly upping the heat on this run can't rule out some where in the SE hitting 35c 95F on the 2nd given these temps are at 2pm

 

Temperatures on the 3rd slightly lower peaking around 29c in the east fresher air in the far west

 

Edited June 25, 2015 by Summer Sun

[Man With Beard]

^{GFS 06Z in FI shows a possibility I have been watching, which is of the heat building again from the south once the first thundery low has passed through:}

 

[Nick L]

ECM 2m temps get up to 33c next Thursday fairly widely across the SE, so the usual hot spots would see 35c on that you would think.

[Summer Sun]

ECM 2m temps get up to 33c next Thursday fairly widely across the SE, so the usual hot spots would see 35c on that you would think.

 

Not far off the July record either which is 36.5c probably quite not a record breaker but still very significant for early July

[Nick L]

Not far off the July record either which is 36.5c probably quite not a record breaker but still very significant for early July

 

I personally don't think the record is in danger. But certainly could be the hottest spell of weather since July 2006. The decent model consistency continues, and as much as I despise such temperatures it's certainly interesting at least. 

 

The ECM also gives a lovely thundery breakdown next weekend.

[Summer Sun]

26c at 2am in the south east not often you see that sort of heat at that time of the morning almost impossible for sleeping

 

[Harsh Climate]

Absolutely mouthwatering charts! Not just because of the potential very high/record temperatures. But because in this country this the holy grail of severe home grown thunderstorm potential! (If this was winter I would compare these charts to a 3/4 day easterly with -15 uppers.)

 

http://www.wetterzentrale.de/pics/Rtavn1802.gif

http://www.wetterzentrale.de/pics/Rtavn18017.gif

 

Hot humid air in place with high temperatures expected

 

http://www.wetterzentrale.de/pics/Rtavn1801.gif

 

little circulation/low pressure slowly encroaching from the west adding extra instability and moisture into the mix 

 

http://www.wetterzentrale.de/pics/Rtavn1809.gif

 

And a feed of winds coming off the hotter/dry continent.

 

 

 

So really this is as good as it gets, unless there is some huge downgrades expect some spectacular thunderstorms in places! If these charts remain similar come the end of the weekend, we will start seeing some phenomenal rain totals and I think flooding would be potentially the main concern.

Edited June 25, 2015 by Harsh Climate

[nick sussex]

French forecasters now more confident that temps could easily exceed 35c in parts of France, with some areas seeing 40+. Nighttimes likely to be generally 20-22.

 

They think there is a chance some records could be challenged for July.

 

I wouldn't be surprised though if London turned out to be hotter at night than here with the heat Island effect making it feel awful, I don't envy anyone having to use the Underground which is likely to be hideous.

Edited June 25, 2015 by nick sussex

[knocker]

Huge downgrade for Cornwall

Chart weatherbell

 

[Frosty.]

The Gfs 6z shows a full on Spanish plume event next week with temperatures soaring, by later next week as high as 33-35 celsius in the south, the heatwave comes in two parts and there is also a lot of thunderstorms breaking out. If anything like the 6z verifies we are in for a nationwide heatwave with plenty of dry and sunny weather and intense storms with very high humidity, longevity wise, I hope the heat becomes entrenched beyond next week...bring it on I say!!

[Harsh Climate]

Huge downgrade for Cornwall

Chart weatherbell

 

 

Only because they wold be getting thrashed by vicious storms! That the temps would be lower. 

[Evening thunder]

The last time the 20c 850 got into the UK was for a few hours in August 2003, this scraped the se corner so its a rare thing to happen. The ECM gets the 22c just into the south coast and widely 21's right up into northern England which would be stunning for the UK.

 

According to the archive charts it was over part of the south on all days from the 5th-10th, except for the 8th. on the 6th was up to 22C, while the record broke under slack conditions on the 10th

 

However I don't know of any other events with more than brief flirtations with it and the sun is also a bit stronger now than August, so if we do get the 20C uppers covering a decent portion of England and clear skies I think we'd probably see the mid-30's in some places.

Brief plumes with slightly lower uppers produced highs such as 33C at the end of June 2011.

[Man With Beard]

http://www.meteociel.fr/modeles/gefs_table.php?ext=1&x=306&y=141&ville=Londres

Latest GFS ensembles, and they just keep getting more extreme. 20 out of 21 members exceed 17C at 850 at some stage, and 17 out of 21 exceed 19C. Several members have virtually continuous heat for several days, one staying above 20C for five whole days.

This is totally unprecedented for a forecast for D5-D10. I would bet even the ensembles for London in 2003 wouldn't have matched this. Clearly record temperatures are not guaranteed, and a shift of the epicentre of the plume could still occur (and do I sense many of us are actually waiting for a downgrade as it seems no other direction is possible). But, at this point, I wouldn't want to go on record saying that nothing special is going to happen next week. For me, there are record-breaking scenarios in that ensemble pack, and as T0 approaches, they are not backing off.

Under normal circumstances, I would take one look at this ensemble pack, one look at the other models, and I would definitely forecast 90F in the SE next week, and I would now go as far as to say 50/50 chance of reaching 95F. (BTW, that means 50% chance of not reaching it too )

Edit: I stand corrected on 2003 above, thank you!

Edited June 25, 2015 by rjbw

[Guest]

Ideally we want these storms to hold off as a potential indicator to a quicker breakdown from the south west. Lets get some proper heat in first as storms and potentail inbound MCS will leave lots of decaying matter about along with cloud etc.

[Frosty.]

The GEFS 6z mean is painting a very summery outlook, not just next week, further ahead too, especially across the south with at least +15 T850 hPA making inroads from the south by next midweek and even across the north and west there is widespread +10 850's which converts to mid 20's celsius. The south and east are likely to reach 30 celsius plus, actually, if the ops continue being so bullish about the upcoming hot spell, I think the south and east will have low to mid 30's c later next week.. low to mid 90's F. I think a heatwave is going to happen, there will be lots of hot sunshine, increasing humidity and a growing risk of intense storms, both home grown and imported from the near continent, exciting times.

Edited June 25, 2015 by Frosty.

[Summer Sun]

GFS updating and so far so good very steady so far inline with the 06z

 

 

Temperatures on Monday getting close to the mid 20's in parts of the south ahead of the hotter air

 

 

By Tuesday they shoot up mid to high 20's widely for England and Wales fresher in Scotland though 19c in Aberdeen will be a major improvement

 

Edited June 25, 2015 by Summer Sun

[stainesbloke]

Ideally we want these storms to hold off as a potential indicator to a quicker breakdown from the south west. Lets get some proper heat in first as storms and potentail inbound MCS will leave lots of decaying matter about along with cloud etc.

Yes, would be preferable to keep the heat and sunshine for as long as possible before a thundery and cooler breakdown. July could be similar to certain summers in the 80's and 90's where there'd be heat, storms, then a reload of heat. We are overdue that for sure!

[SizzlingHeat]

Not liking the 12z so far. Jet stream buckling much further east thus pressure to the east is weaker and even some rain tuesday morning. I did think the 6z had shunted things east this morning but were still fine. Gfs still progging things further east. Cant see the 30s coming off if the evolution continues. Pressure too slack and low pressure closer. Always too good to be true in this country.

[mhielte]

Not liking the 12z so far. Jet stream buckling much further east thus pressure to the east is weaker and even some rain tuesday morning. I did think the 6z had shunted things east this morning but were still fine. Gfs still progging things further east. Cant see the 30s coming off if the evolution continues. Pressure too slack and low pressure closer. Always too good to be true in this country.

???

 

I disagree. It looks in line with the 6z so far, and temperatures are already forecast to hit 28C on Tuesday. Are you looking at the right charts/timeframes?

 

Wednesday has 30-32C across much of England, too.

Edited June 25, 2015 by mhielte

[cheese]

???

 

I disagree. It looks in line with the 6z so far, and temperatures are already forecast to hit 28C on Tuesday. Are you looking at the right charts/timeframes?

 

Wednesday has 30-32C across much of England, too.

No, he's right - the warm uppers are pushed away much more quickly on this run. 06Z had 18C uppers over most of England at 8am Thursday but now it has 16C uppers pushed away into the SE with 12C uppers elsewhere. So not as hot. Also compare 2m temperatures on Thursday next week on 06Z vs 12Z - big difference.

Edited June 25, 2015 by cheese

[Polar Maritime]

It's always helpfull for members to post charts to back up there posts. Saves all the complications ☺

Edited June 25, 2015 by Polar Maritime

[cheese]

06z

 

12z

 

 

Edited June 25, 2015 by cheese

[mhielte]

No, he's right - the warm uppers are pushed away much more quickly on this run. 06Z had 18C uppers over most of England at 8am Thursday but now it has 16C uppers pushed away into the SE with 12C uppers elsewhere. So not as hot. Also compare 2m temperatures on Thursday next week on 06Z vs 12Z - big difference.

Yes, quite right. I should have waited for Thursday to appear on the 12z. It does look further east. Lets hope it's a slight outlier in terms of its progression.

 

Heat builds back Friday though, so not a total disaster!

Edited June 25, 2015 by mhielte

[Supacell]

The heat does get in briefly on the 12z for Tues/Weds but it is brief and quickly washed away to the east by thunderstorms. However, I think peoples upset may be premature as it is a brief retreat before the heat builds back for the weekend. Remember though, this is one run of one model for something 5 days away - there will be changes.

 

As I thought, Friday looks baking hot across most of the UK

Edited June 25, 2015 by Supacell