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Model output discussion - August hot spell - how hot, how long?


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Just now, Stabilo19 said:

I would've said the opposite? Temperatures here are suppressed, still only 23-24 under cloud and yet we're forecast to reach 30 later.. 

 

Look at the satellite image - lots of clear skies moving up from the south. Forecast I heard earlier was for only limited breaks. When you get sun, the temperature will rocket so 30C is more than possible.

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1 hour ago, B87 said:

London looks like it will have its hottest week since 2003, though it'll be a tall order to match the 1976 spell of 16 consecutive days at 31c+.

Did 06, 13 or 18 no see sustained 90F spells.

1 hour ago, MattStoke said:

Interestingly, the models have reduced tomorrow’s highest temperatures slightly but increased Saturday’s. Could be that Saturday gives a slightly higher chance of breaking records.

I think some people are a bit OTT on record potential. Last week had extremely high uppers and sprung a suprise but lapse rates were nothing spectacular. Uppers are a bit lower this time. 33-35C on Sat-Tues is still very probable though even at non-Heathrow.

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7 minutes ago, summer blizzard said:

Did 06, 13 or 18 no see sustained 90F spells.

Nothing compared to this. The current weekly forecast only compares to August 2003 or June/July 1976.

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11 minutes ago, Stabilo19 said:

I would've said the opposite? Temperatures here are suppressed, still only 23-24 under cloud and yet we're forecast to reach 30 later.. 

 

To be honest the clearance has come here quicker than I thought, although on satellite there's clearly a wedge of stubborn cloud from London to Birmingham down to the south west taking a touch longer to break. I'd expect London to be in the sun in the next 90mins. I suspect some late maxes on offer today 6-7pm in many locations in the south east although temps will responded quickly, already 25C here, parts of Kent/Sussex probably already pushing into the high 20s. 

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24 minutes ago, johnholmes said:

  Which is why matching those with the nearest GFS or ECm is useful, the NOAA charts will give you an accurate idea of the mean pattern of troughing and ridging plus the mean upper flow. You can then extraploate surface detail off the nearest ops... This is a very successful method that ive been employing for some time now, and its certainly more stable and accurate for that timeframe then trying to decide which op has found a new trend.

Very true mushy, as usual with a great deal of care, but for those interested it is worth giving it a go. Not just now but in the hectic search for cold come the winter!

 

What sort of temperature would you expect in the coming days John? In the Westmidlands, we have hardly seen much sun over the past few days with subdued temperatures, we have seen consistnlty lower temperatures compared to the forecast. Not sure if we will get to 30C tomorrow. Would like to see some sun even if the temperature is low 20C 😀

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I doubt we're going to beat the temp record by day but some other records could go including for night times lowest and if this crazy GFS 6z comes to life we could be looking at CET for August being well over 20C which would be a record for warmest month. Kiss goodbye to Aug 1995 and 2003 CET. 

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6 minutes ago, Alderc said:

 I suspect some late maxes on offer today 6-7pm in many locations in the south east although temps will responded quickly, already 25C here, parts of Kent/Sussex probably already pushing into the high 20s. 

Yes that is highly likely, especially in places where cloud has surpressed temperatures during the morning hours.

We are now starting to advect the hotter stuff into the region.

I do somewhat agree with SB, I think the highest ever temperature is probably a tall order as the air isn't quite as extreme as it was last week nor on the record breaking day last year. With that being said 36-37c seems likely to me in the hotspot.

Depending on how much cloud cover there is in theory Saturday could be even hotter but there is considerable uncertainty about just how much cloud does end up lingering.

What wouldn't surprise me is if either Fri/Sat end up in the top 5 hottest ever days (36.8c required for that). May get another shot at that mid week next week as the air shifts back southerly ahead of any possible attempt at a breakdown from the west.

Probably going to be one of the hottest spells the SE has seen. It may not be quite as extreme as August 03 nor as long as 76, but still likely to be a historic week IMO. I'm guessing at least the next 6-7 days will see maxes above 32c from Friday onwards.

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UKV has done well for today so far - see post above. 
Hopefully start that run of 30C today! 29C maybe more realistic though. (Recent UKV still going for a high of 29C later)

36C+ is definitely still on for tomorrow and probably Saturday as well! 

Friday 14:00

B2ABA03C-D7E5-4D5E-85C4-37D123EA2E7C.thumb.png.877baca334a2be602b08645fa83fb5ca.png
 

Saturday 15:00

C0851268-17AE-4FB1-A4FC-AD092AB27ABF.thumb.png.28c802964379d40d1351c81c1920bde2.png

 

Low twenties for me but keeping an eye on this band of showers - could be thunderstorms/downpours sweeping across parts of Scotland tomorrow. (Met Office mention thundery showers in my regional forecast)

DD6B5B98-7D4D-4289-BEF1-D42662AEFCDE.thumb.png.da6496d90a4716d49244a99a5861a213.png

Bit of cloud bubbling up in the SW - wee risk of something popping up!

As ever take any cloud cover/precipitation charts at this range with a pinch of salt! 

Have a good day! 

Edit: Heating up!

6C332BA2-0A7A-47C6-BF6F-0F4E2E52B34F.thumb.png.f3e04839469ccb3cd5e721c1217e758e.png

Edited by Mr Frost
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Minimum temperatures a certainly something to keep an eye on.  In a lot of places temperatures will not drop much below 20°C for days on end (quite amazing to see the forecast here with minimum temperatures in the 18-19°C region).  I'm expecting the CET to skyrocket!

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1 hour ago, summer blizzard said:

Did 06, 13 or 18 no see sustained 90F spells.

I think some people are a bit OTT on record potential. Last week had extremely high uppers and sprung a suprise but lapse rates were nothing spectacular. Uppers are a bit lower this time. 33-35C on Sat-Tues is still very probable though even at non-Heathrow.

The slightest tweaks in gradients (given current plots) would easily take us at the very least into record matching=or beyond territories.

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Gfsp goes for 37 tomorrow Heathrow area and 37 Saturday towards gravesend area in Kent both days in the south east widely 35/36 also extremely warm night Friday night some parts no lower than 25 degrees, stay hydrated all 👍

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1 hour ago, summer blizzard said:

Did 06, 13 or 18 no see sustained 90F spells.

 

 

1 hour ago, B87 said:

Nothing compared to this. The current weekly forecast only compares to August 2003 or June/July 1976.

July 2006 didn’t see a sustained 32c/90f spell, but at Heathrow there was a sustained 30c+ spell. 6 consecutive days between the 16th and 21st, and then after a couple of days of slightly cooler temps we had another 4 consecutive days at 30c+:

C4ABB924-BD02-4DC6-A80F-89A0C677FE2B.thumb.jpeg.6e28e493ce6e344d8ac7f0e3ce3c5f10.jpeg
 

July 2018 at Heathrow had 14 out of the 31 days in the month at 30c+. Two spells of 5 consecutive days:

E3609627-962C-4ED4-8FBA-09AA894AB259.thumb.jpeg.257c0d9d8d3d607292a9e032e611924a.jpeg
 

2018 also had a further 4 days at 30c+ at the start of August:

8BD08986-8D5E-4D9E-B43B-E1095347620C.thumb.jpeg.58137ce87601927957b2d82d37a48d68.jpeg

I think if we were to get several consecutive days into the mid 30s that would be pretty exceptional. 

Edited by danm
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1 hour ago, kold weather said:

Yes that is highly likely, especially in places where cloud has surpressed temperatures during the morning hours.

We are now starting to advect the hotter stuff into the region.

I do somewhat agree with SB, I think the highest ever temperature is probably a tall order as the air isn't quite as extreme as it was last week nor on the record breaking day last year. With that being said 36-37c seems likely to me in the hotspot.

Depending on how much cloud cover there is in theory Saturday could be even hotter but there is considerable uncertainty about just how much cloud does end up lingering.

What wouldn't surprise me is if either Fri/Sat end up in the top 5 hottest ever days (36.8c required for that). May get another shot at that mid week next week as the air shifts back southerly ahead of any possible attempt at a breakdown from the west.

Probably going to be one of the hottest spells the SE has seen. It may not be quite as extreme as August 03 nor as long as 76, but still likely to be a historic week IMO. I'm guessing at least the next 6-7 days will see maxes above 32c from Friday onwards.

Already 29.4C and climbing fast. I would say that low to mid 30's is definitely on the cards today.

I'm on the side of the North Downs (Guildford) and can see Heathrow so expect the run of 30+ days to start from today

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I posted a tweet earlier and it went something like in 1976 Heathrow saw 16 consecutive days above 31C, although only managed 6 on the trot above 32C and 4 above 33C. Southampton managed 3 days above 34C, the only other time I believe the same location has record 3 days above 34c in the UK is Heathrow in Aug 1990. The longest run of 32C/90f days I could find from 76 was actually in Bournemouth and 7 days. Someone else maybe able to beat these if they look closely.

So looking at the above 3 max's at or above 34C in the same location seems the limit of the extreme heat and longevity combination in the UK......to date...... 

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7 minutes ago, kold weather said:

09z ICON showing a max of 35c as well for tomorrow, which is a slight upping from the earlier 06z run.

clark3r, where are you seeing the GFSp?

Type gfsp charts in google and it’s one of two’s models 

 

image.thumb.png.91f7c003fca6ed61aa0503340f54d924.png

 

image.thumb.png.30011a6489caf0d9a82ae75467525f62.png

Edited by clark3r
https://www.theweatheroutlook.com/charts/gfspara/06_60_uk2mtmp.png?cb=0608202006
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3 minutes ago, clark3r said:

Type gfsp charts in google and it’s one of two’s models 

 

image.thumb.png.30011a6489caf0d9a82ae75467525f62.png

I have to say it does seem like the new GFS upgrade has a much better handle on the surface maxes compared with the current operational run. 

As you say, Friday and Saturday are pretty outrageous with fairly widespread 34-36c in the SE on both days. Sunday also gets a 35!

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2 minutes ago, kold weather said:

I have to say it does seem like the new GFS upgrade has a much better handle on the surface maxes compared with the current operational run. 

As you say, Friday and Saturday are pretty outrageous with fairly widespread 34-36c in the SE on both days. Sunday also gets a 35!

I love the heat but think this may be a bit unbearable for some particularly with night temps staying so warm, by the looks of things mid thirties may last most of next week and even a chance it may go higher, fascinating times, the 2003 heatwave I wasn’t looking at models then so I don’t think I’ve seen charts like this before 👍

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2 minutes ago, Mike Poole said:

The difference in uppers between the GFS and the parallel at just T42 on the 6z suite  is quite ridiculous:

2BE26C05-3D5E-40F8-9509-AC1435115D2C.thumb.png.4da1c0274d7cbb802a4126099d632b24.png6F47EFFA-B414-409C-9F48-C310ACB0ED5F.thumb.png.2d305dd33991e63f032e256848b5a250.png

Oh my the GFS Parallel looks absolutely crazy... Almost seeing 22'c 850hpa temps along the south coast mental.

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10 minutes ago, Ben Sainsbury said:

Oh my the GFS Parallel looks absolutely crazy... Almost seeing 22'c 850hpa temps along the south coast mental.

Indeedy, with some decent sunny spells that would probably be enough topple last weeks high..

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2 hours ago, Djdazzle said:

Today is a case in point as to why cloud amounts on the models shouldn’t be taken as gospel. It’s breaking up much more readily than many of the models were indicating. Should be a sunny and hot afternoon down south.

It’s been the opposite here. Sunny in the morning but dull with thick cloud now. Thick enough to produce some light drizzle. 

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1 hour ago, Mandrake said:

Already 29.4C and climbing fast. I would say that low to mid 30's is definitely on the cards today.

I'm on the side of the North Downs (Guildford) and can see Heathrow so expect the run of 30+ days to start from today

Can’t see a 30c today looking at the current T2m’s  ???

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