Heavy Weather 2013
04 August 2020 20:10:25

With the Aperge model showing temperatures of at least 36C on Friday we can now start thinking of another top five record hottest day.


1) 38.7C 25 July 2019 


2) 38.5C 10 August 2003


3) 37.8C 31 July 2020


4) 37.1C 3 August 1990


5=) 36.7C 9 August 1911


5=) 36.7C 1 July 2015


This thread is for short term model discussion which can also be used on the day itself. 


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
Heavy Weather 2013
05 August 2020 05:32:16
Aperge still Going for 36-38C.

MetOffice App is showing 37C still for Heathrow and even my iPhone app forecast is showing 35C now. Higher than last Friday ahead of the event.

Arome almost into range. If that shows 37C Top four is on.
Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
Rob K
05 August 2020 06:48:49
Arpege 0Z has knocked a degree off, down from 37 to 36.
Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
Heavy Weather 2013
05 August 2020 06:54:03

IPhone App has just upgraded the temperature for my location on Friday to 36C.


I’d like a nice clean top 5. I hate it when two dates share a record.


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
superteacher
05 August 2020 10:48:49
Friday now showing 38C @ Heathrow.
xioni2
05 August 2020 11:02:50

There will be a katabatic effect from the Downs again on Friday, but the air mass isn't as hot as last Friday. 36C looks more reasonable to me.

Heavy Weather 2013
05 August 2020 11:05:08

Originally Posted by: superteacher 

Friday now showing 38C @ Heathrow.


Blimey. What are they seeing that other models aren’t.


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
superteacher
05 August 2020 11:06:30

Originally Posted by: xioni2 


There will be a katabatic effect from the Downs again on Friday, but the air mass isn't as hot as last Friday. 36C looks more reasonable to me.



Not disputing what you say, but surely the Met Office know this too? They seem very confident of a rounded 38C. And they usually err on the side of caution.

Quantum
05 August 2020 11:11:02

The 850hpa temps are somewhat unremarkable but last week demonstrates you don't need high uppers.


Still flabbergasted by the 25C 850hpa temp in SW England last year, suprised it didn't attract more attention at the time. Must be a record for the UK.


And had it not been for the airmass being extremely wet we could have seen 40C with those uppers rather than the upper twenties we actually saw.


 


Twitter: @QuantumOverlord (general), @MedicaneWatch (medicane/TC stuff)
2023/2024 Snow days (approx 850hpa temp):
29/11 (-6), 30/11 (-6), 02/12 (-5), 03/12 (-5), 04/12 (-3), 16/01 (-3), 18/01 (-8), 08/02 (-5)

Total: 8 days with snow/sleet falling.

2022/2023 Snow days (approx 850hpa temp):

18/12 (-1), 06/03 (-6), 08/03 (-8), 09/03 (-6), 10/03 (-8), 11/03 (-5), 14/03 (-6)

Total: 7 days with snow/sleet falling.

2021/2022 Snow days (approx 850hpa temp):

26/11 (-5), 27/11 (-7), 28/11 (-6), 02/12 (-6), 06/01 (-5), 07/01 (-6), 06/02 (-5), 19/02 (-5), 24/02 (-7), 30/03 (-7), 31/03 (-8), 01/04 (-8)
Total: 12 days with snow/sleet falling.
Ally Pally Snowman
05 August 2020 11:18:36

Looks like 850s will be about 18c Friday afternoon in the SE. So 37/38c will be top end. Just shy of the record is my guess.


Bishop's Stortford 85m ASL.
superteacher
05 August 2020 11:41:14

Originally Posted by: Quantum 


The 850hpa temps are somewhat unremarkable but last week demonstrates you don't need high uppers.


Still flabbergasted by the 25C 850hpa temp in SW England last year, suprised it didn't attract more attention at the time. Must be a record for the UK.


And had it not been for the airmass being extremely wet we could have seen 40C with those uppers rather than the upper twenties we actually saw.


 



That was when we had that vile North Sea undercut - what a waste of such high uppers!

Rob K
05 August 2020 12:17:08
BTW does Euro4 always underdo temps this much? At 1pm on Friday it reckons it will only be 28C in London.

https://modeles14.meteociel.fr/modeles/euro4/runs/2020080506/euro4_uk1-41-54-0.png?05-11 

Yateley, NE Hampshire, 73m asl
"But who wants to be foretold the weather? It is bad enough when it comes, without our having the misery of knowing about it beforehand." — Jerome K. Jerome
picturesareme
05 August 2020 12:40:42

Originally Posted by: Heavy Weather 2013 


With the Aperge model showing temperatures of at least 36C on Friday we can now start thinking of another top five record hottest day.


1) 38.7C 25 July 2019 


2) 38.5C 10 August 2003


3) 37.8C 31 July 2020


4) 37.1C 3 August 1990


5=) 36.7C 9 August 1911


5=) 36.7C 1 July 2015


This thread is for short term model discussion which can also be used on the day itself. 



I'm  not sure why the metoffice dismiss the otherwise accepted high of 38C (100f) at Greenwich back in 1911.  

superteacher
05 August 2020 13:03:19

Originally Posted by: picturesareme 


 


I'm  not sure why the metoffice dismiss the otherwise accepted high of 38C (100f) at Greenwich back in 1911.  



Dodgy exposure, and it’s a lot higher than most surrounding stations. Then again, Gravesend was often much higher than other local stations.

TimS
  • TimS
  • Advanced Member
05 August 2020 13:22:39

If we're treating this as the general heatwave thread rather than just the Friday record one, then worth noting it's now at 28C at Mildenhall airfield (all those plane exhausts and tarmac runways no doubt). Only 2pm so a couple of hours of heating time left with 850s stable, so long as the sun stays out.


Tomorrow could be a tad disappointing on the sunshine front. BBC news just now forecasting 27C, models showing between 27 and 30 depending where you look. GFS shows largely clear whereas the more local scale ICON and Arpege show a lot of mid and low level cloud.


Brockley, South East London 30m asl
Heavy Weather 2013
05 August 2020 13:25:24

Originally Posted by: TimS 


If we're treating this as the general heatwave thread rather than just the Friday record one, then worth noting it's now at 28C at Mildenhall airfield (all those plane exhausts and tarmac runways no doubt). Only 2pm so a couple of hours of heating time left with 850s stable, so long as the sun stays out.


Tomorrow could be a tad disappointing on the sunshine front. BBC news just now forecasting 27C, models showing between 27 and 30 depending where you look. GFS shows largely clear whereas the more local scale ICON and Arpege show a lot of mid and low level cloud.



I think this is Ok. Specifics about Friday are most important . But as you known conditions leading up to the day are equally important as they could have an effect also.


I have also noted this increase in cloud for tomorrow. I suspect any breaks and the temperatures will quickly climb. 


What shocked me on my lunchtime walk was how brown everything is again here


Mark
Beckton, E London
Less than 500m from the end of London City Airport runway.
superteacher
05 August 2020 13:30:26

Originally Posted by: TimS 


If we're treating this as the general heatwave thread rather than just the Friday record one, then worth noting it's now at 28C at Mildenhall airfield (all those plane exhausts and tarmac runways no doubt). Only 2pm so a couple of hours of heating time left with 850s stable, so long as the sun stays out.


Tomorrow could be a tad disappointing on the sunshine front. BBC news just now forecasting 27C, models showing between 27 and 30 depending where you look. GFS shows largely clear whereas the more local scale ICON and Arpege show a lot of mid and low level cloud.



I think the cloud will break, especially the further east you are.


Temps have certainly shot up today here - not surprised that Mildenhall is reporting 28. Bit of mid-level cloud making the sunshine a bit hazy from time to time.

GezM
  • GezM
  • Advanced Member
05 August 2020 13:43:28

Personally I'm not buying the 38C max at Heathrow forecast by the Met Office for Friday. I noticed that Hampton Court, just a few miles away is forecast by the Met Office to reach 33C. I could understand perhaps a 2C difference, but not 5C! There must be some human tweaking of numbers going on, as others have mentioned, probably as a result of last Friday. 


Living in St Albans, Herts (116m asl)
Working at Luton Airport, Beds (160m asl)
superteacher
05 August 2020 13:45:50

Originally Posted by: Heavy Weather 2013 


 


I think this is Ok. Specifics about Friday are most important . But as you known conditions leading up to the day are equally important as they could have an effect also.


I have also noted this increase in cloud for tomorrow. I suspect any breaks and the temperatures will quickly climb. 


What shocked me on my lunchtime walk was how brown everything is again here



if it does break quite widely, temps will exceed 30C quite easily I feel.

superteacher
05 August 2020 13:49:37

Originally Posted by: GezM 


Personally I'm not buying the 38C max at Heathrow forecast by the Met Office for Friday. I noticed that Hampton Court, just a few miles away is forecast by the Met Office to reach 33C. I could understand perhaps a 2C difference, but not 5C! There must be some human tweaking of numbers going on, as others have mentioned, probably as a result of last Friday. 



I think a 37 is on though. Maybe the 38 would be a rounded 37.5.


But they seem very confident and it’s only 2 days away.

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