Model output discussion - into July 2020

[Guest]

Have to say I'm getting really frustrated with the output, with a very nimby perspective here all the models really are indicating a lot of afternoon cloud now Weds, Thurs and Friday. Arpege out on its own for here with maxes of 32C and sun most of the day, last Friday it apparently clouded over by 1-2pm, could be before Midday this Friday.  

[Man With Beard]

1 minute ago, Alderc said:

Have to say I'm getting really frustrated with the output, with a very nimby perspective here all the models really are indicating a lot of afternoon cloud now Weds, Thurs and Friday. Arpege out on its own for here with maxes of 32C and sun most of the day, last Friday it apparently clouded over by 1-2pm, could be before Midday this Friday.  

You do realise you are in the absolute A1 position for an extended heatwave in the coming days down there in Bournemouth? The ECM in particular seems keen on making you a few degrees hotter than just 50 miles away on some days, and the GFS looks similar.

Or is it more stressful being in a spot with potential, than in a spot with none at all

[stodge]

Evening all

After last night's model volatility and variability, where are we this fine summer's evening (at least in lowland East London)?

ECM 12Z OP pushes the hottest of the weather to next Wednesday - the T+192 chart:

This looks like a humid and thundery rather than a hot and sunny chart - the HP has eroded to both east and west but nothing is happening too quickly so any storms are going to be locally significant.

The animated 850HPA chart on the GFS 12Z OP tells its own story - oscillations of heat from Iberia through France but coming up just short. The 20c 850 line never gets to the UK so very warm certainly but not hot.

The T+192 has an E'ly not a S'ly so again the accent is on very warm, humid and possibly thundery conditions especially for the south but as always with an E'ly, the further north and west, the better for settled weather.

GEM still keeps the heat on Tuesday next week and by Wednesday:

Growing agreement on the trough developing to the south so cutting off the direct feed of hot air - I suspect rather than strong heat we'll see high humidity and a growing risk of storms.

[Guest]

1 minute ago, Man With Beard said:

You do realise you are in the absolute A1 position for an extended heatwave in the coming days down there in Bournemouth? The ECM in particular seems keen on making you a few degrees hotter than just 50 miles away on some days, and the GFS looks similar.

Or is it more stressful being in a spot with potential, than in a spot with none at all

Oh I know I am, however the first sniff of that was meant to be tomorrow, which now now seems unlikely, some models have Thursday now struggling past 21/22c, Friday looks cloudy early. Not exactly a good start and then there's a bundle of uncertainty over the weekend. So its a pretty nervy time.... 

[qwertyK]

Just one day at 33C here in southern Essex. One day at 34C for Heathrow too. I mean there's still time for it to change but I honestly think everyone got carried away with some 40C heatwave run on ECM. Can't lie I'll be glad if we don't get that hot of a day as I'd rather not have another weather record broken for the second consecutive year

[SMU]

The threads been a bit derailed this eve with a lack of analysis.

For the hot weather to remain in situ over England on Sat the wave that has been highlighted for 2 days now would need to track through Scotland & SSW exiting Cornwall thus protecting a big swathe of England from the cooler uppers from the North.

The GFS has been to progressive with the cool air & the UKMO has been the opposite. Usually the GFS moves to the UKMO however seen by the charts below which are the same day 24 hours apart (12z runs ) UKMO has corrected SE & the GFS has corrected NW both by about similar amounts so that we are beginning to converge on the 16c Line straddling the SE & the 8c line somewhere over the NW

UKMO yesterday 120 first V todays 96

GFS yesterday 120 V todays 96

 

What we actually have is minimal corrections from day 5 down to 4 > A range of about 50- 75 miles is well within natural variability- & for once the models are perhaps beginning to meet in the middle halfway house.

Sadly for some the correction SE from the UKMO swings the surface temps down by around 10c for some going from mid 30s to mid / high 20s.

With that annoyance out of the way heat builds back from the SE but its not quite the major heat for records which for most is fine.

Some models still hold back the wave to the North & still scope for it to move either way but higher probability would be a move NW not SE.

Lets see what tomorrow brings.

[kold weather]

11 minutes ago, qwertyK said:

Just one day at 33C here in southern Essex. One day at 34C for Heathrow too. I mean there's still time for it to change but I honestly think everyone got carried away with some 40C heatwave run on ECM. Can't lie I'll be glad if we don't get that hot of a day as I'd rather not have another weather record broken for the second consecutive year

Worth noting that the higher resolution models are both going with maxes on the 35-36c range and peak hotspots could well end up another 1c beyond that.

Friday's max likely north of 35c...my guess would be something like 36.5c based in current higher resolution models.

Worth remembering the ECM and GFS had 32-33c for last Friday...ended up with fairly widespread 34-36c with 37.8c at Heathrow. The global models like ECM and GFS aren't the best at picking up absolute maxes.

I think for the south after Friday your looking at several days in the 26-30c range, maybe the odd 31-32c in favoured spots.

Further north may not be great, especially if cloud comes on from the North sea on that NE flow.

Edited August 4, 2020 by kold weather

[SMU]

Aperge is 37c ^^
 

 

[qwertyK]

6 minutes ago, kold weather said:

Worth noting that the higher resolution models are both going with maxes on the 35-36c range and peak hotspots could well end up another 1c beyond that.

Friday's max likely north of 35c...my guess would be something like 36.5c based in current higher resolution models.

Worth remembering the ECM and GFS had 32-33c for last Friday...ended up with fairly widespread 34-36c with 37.8c at Heathrow. The global models like ECM and GFS aren't the best at picking up absolute maxes.

I think for the south after Friday your looking at several days in the 26-30c range, maybe the odd 31-32c in favoured spots.

Further north may not be great, especially if cloud comes on from the North sea on that NE flow.

We'll see closer to the time I guess.  However we did also have a point late June where there was predicted 3 days of 30+ heat for SE/EA with some places forecasted up to 35C locally but it turned out to be a one day wonder at 33.4C

[clark3r]

Gfsp still looking very hot Friday hot in south east Saturday 

 

[kold weather]

5 minutes ago, clark3r said:

Gfsp still looking very hot Friday hot in south east Saturday 

 

Yes GFSp looks like it has a better handle on max temperatures, pretty close to the Arprge and UKV as well.

Still time for cloud to come over faster than expected but in confident of at least a 35c on Friday.

[B87]

16 minutes ago, qwertyK said:

We'll see closer to the time I guess.  However we did also have a point late June where there was predicted 3 days of 30+ heat for SE/EA with some places forecasted up to 35C locally but it turned out to be a one day wonder at 33.4C

London did get 3 days of 30c in late June.

24. 32.6c

25. 33.4c

26. 31.0c

[Djdazzle]

GFS 18z is a warmer run for most over the weekend, and Monday is looking warmer too.

[Mike Poole]

GFS 18z, T78

I think this is now converging on what we might get on Friday into Saturday  now.

More interest for me, is early next week, here T144, needs firming up with more model runs....

Things are coming, from the south!!

Edited August 4, 2020 by Mike Poole

[Djdazzle]

And as if modelling was difficult enough at the moment, there is low pressure over France. I’d like to see that modelled a bit further west, then things would turn very hot again.

[Cheshire Freeze]

5 minutes ago, Mike Poole said:

GFS 18z, T78

I think this is now converging on what we might get on Friday now.

More interest for me, is early next week, here T144, needs firming up with more model runs....

Things are coming, from the south!!

Trouble is, there's a flow off the N Sea which keeps temperatures suppressed for many ahead of the advancing low and associated thunderstorms from the S.

[Scorcher]

4 minutes ago, Mike Poole said:

GFS 18z, T78

I think this is now converging on what we might get on Friday now.

More interest for me, is early next week, here T144, needs firming up with more model runs....

Things are coming, from the south!!

Yes looking good early next week. However the temperature charts on the GFS don't look too impressive- I'm struggling to work out why this might be? Seems to be a flow south of east to me for the southern half of the UK with a short sea track and with impressive uppers you'd expect better than the mid 20s.

[Scorcher]

Just now, CreweCold said:

Trouble is, there's a flow off the N Sea which keeps temperatures suppressed for many ahead of the advancing low and associated thunderstorms from the S.

This only looks an issue for the far north of England northwards though- the flow south of around Leeds is actually more from the continent I think.

[Cheshire Freeze]

2 minutes ago, Scorcher said:

Yes looking good early next week. However the temperature charts on the GFS don't look too impressive- I'm struggling to work out why this might be? Seems to be a flow south of east to me for the southern half of the UK with a short sea track and with impressive uppers you'd expect better than the mid 20s.

Surface winds are ENEly, I think that's the reason. 

[Djdazzle]

 

Come on, you all know better than to pay attention to GFS 2m temp charts!

Wind direction crucial though.

Edited August 4, 2020 by Djdazzle

[Cheshire Freeze]

2 minutes ago, Scorcher said:

This only looks an issue for the far north of England northwards though- the flow south of around Leeds is actually more from the continent I think.

 

[Mike Poole]

1 minute ago, Djdazzle said:

Come on, you all know better than to pay attention to GFS 2m temp charts!

Agreed, but who posted them?  I didn’t see any!

[Djdazzle]

Just now, Mike Poole said:

Agreed, but who posted them?  I didn’t see any!

I’m sure someone mentioned that they’d looked at the GFS temps a few posts back.

 

[Cheshire Freeze]

A potentially convective and humid period looking possible into next week. S areas look at risk from thunderstorm activity initially before the risk pushes further N.

Models starting to hint at some good lightning potential.

Edited August 4, 2020 by CreweCold

[Djdazzle]

GFS turns into a right mess - somehow manages to generate an upper trough over France, move it north and then park it over the U.K. for 3 days! Hilarious. . .