Model output discussion - into July 2020

[johnholmes]

35 minutes ago, Snowy L said:

Met office have had a shocker this year with their 30 day forecasts. Warm and settled weather has been 2 weeks away for 3 months now according to them.

 

Edited July 31, 2020 by johnholmes
not model related-apologies

[Man With Beard]

ECM clusters appear fairly united on how they expect next weekend to pan out. 

First, that move on heights up through Europe just to our east on D8, which is highly likely to drag hot air with it (in spite of what the GFS 06Z wants).

I've checked the ensemble summary here: https://weather.us/forecast/2643743-london/ensemble/euro, and next Saturday, 90% of runs have a raw 1pm temperature of between 24C and 32C, and yes, in my experience you can also add that 2-3C to these raw temperatures to get to the actual localised maximum, so this suggests 90% of runs would produce between 26C and 35C, not even at the hottest part of the day.

By D10, signs that this may consolidate as a "Sceuro" High, which would maintain a continental flow (cluster 3 the only real dissenter). Should stay hot. 

 

By D12/D13, signs that the block to the east may start to break but various options of what happens next, from breakdown to a fresh injection of heat from the south - too far out to be particularly specific, of course.

Main headline for next weekend, then - Expect a heatwave, probably of the low 30Cs type, small chance of the high 30Cs type

[Mark wheeler]

I know not everyone is a fan of heat so this chart is for you , Cool and wet also Windy .

 

[Frosty.]

20 minutes ago, Man With Beard said:

ECM clusters appear fairly united on how they expect next weekend to pan out. 

First, that move on heights up through Europe just to our east on D8, which is highly likely to drag hot air with it (in spite of what the GFS 06Z wants).

I've checked the ensemble summary here: https://weather.us/forecast/2643743-london/ensemble/euro, and next Saturday, 90% of runs have a raw 1pm temperature of between 24C and 32C, and yes, in my experience you can also add that 2-3C to these raw temperatures to get to the actual localised maximum, so this suggests 90% of runs would produce between 26C and 35C, not even at the hottest part of the day.

By D10, signs that this may consolidate as a "Sceuro" High, which would maintain a continental flow (cluster 3 the only real dissenter). Should stay hot. 

 

By D12/D13, signs that the block to the east may start to break but various options of what happens next, from breakdown to a fresh injection of heat from the south - too far out to be particularly specific, of course.

Main headline for next weekend, then - Expect a heatwave, probably of the low 30Cs type, small chance of the high 30Cs type

Hey Man With Beard, you’re good, you’re really good...and the ECM 0z ens mean backs you up.. great job..for those who thought summer 2020 was over and out..it isn’t, far from it..hats off to Tamara too !

Edited July 31, 2020 by JON SNOW

[mushymanrob]

34.4c at Heathrow..... the hottest July 31st on record, beating the old record of 33.4c set in 1943.

 

[northwestsnow]

Met office now put a warning out for thunderstorms this afternoon across the south East...

[Tim Bland]

36c now official at Kew Gardens..those high res models such as Aperge where not far off after all! Could 37/38c be achieved? Could the Cap be broken after all?

[Frosty.]

17 minutes ago, Tim Bland said:

36c now official at Kew Gardens..those high res models such as Aperge where not far off after all! Could 37/38c be achieved? Could the Cap be broken after all?

Astonishing, in your face Gfs..not even close!!!..I feel a Roy Castle (god rest his soul) record breaker 31st July..for anyone old enough to remember record breakers!!!

 

Edited July 31, 2020 by JON SNOW

[chapmanslade]

22 minutes ago, JON SNOW said:

Astonishing, in your face Gfs..not even close!!!..I feel a Roy Castle (god rest his soul) record breaker 31st July..for anyone old enough to remember record breakers!!!

 

Look at the time on that chart, 18.00 GMT which is 19.00 BST. Looks entirely reasonable to me

[stainesbloke]

Blimey! Record might be under threat, at this rate

[Don]

38 minutes ago, stainesbloke said:

Blimey! Record might be under threat, at this rate

Yep....

[MATTWOLVES 3]

The 6Z means looks pretty promising for this time next week again.. Anybody ready for plume 3!! Just noticed the Exeter update is going for very warm even Hot conditions for the end of next week also... Just like a bus.. Ya wait for ages then 2 or 3 come at the same time..

[Zak M]

37.8c (100F) at Heathrow. This means that even the ARPEGE has underestimated the temps.

Holy bejesus.

[MATTWOLVES 3]

3 minutes ago, Zak M said:

37.8c (100F) at Heathrow. This means that even the ARPEGE has underestimated the temps.

Holy bejesus.

Amazing Zak.. There's climate change for you.. Many years ago you may have needed a run of warm days to end up with this kind of temperature.. These days it appears we can nudge 100F in the space of 48Hours..pretty worrying when you think hard about it.. But it is what it is unfortunately

[Man With Beard]

2 minutes ago, Zak M said:

37.8c (100F) at Heathrow. This means that even the ARPEGE has underestimated the temps.

Holy bejesus.

I think it's worth comparing this temperature with model predicted temperatures, as it will help for understanding the range of temperatures possible from a model estimated temperature in the future

GFS: 31C (until this morning, when it upped to 32C) = 6/7 degrees too low

ECM: 33C = 5 degrees too low 

ARGEPE 36/37C depending on the run = close enough, maybe 1 degree too low?

AROME 36/37C = close enough, maybe 1 degree too low?

[Mr Frost]

UKV chart for 15:00 (Saved this from the 09Z run this morning)

37C for today.

It started off earlier in the week with a high of 32C! Then gradually increased the maximum each day with 36C showing yesterday lunchtime. (Posted in here)

Great stuff from everyone in here this last ten days or so - really enjoyed the build up to this plume! We have got the wonderful high temperature...bring on the spectacular thunderstorms now!  (Keep an eye on the sky - who knows what will pop up!)

Have a good weekend everyone!

Edited July 31, 2020 by Mr Frost

[MattStoke]

20 minutes ago, Mr Frost said:

UKV chart for 15:00 (Saved this from the 09Z run this morning)

37C for today.

It started off earlier in the week with a high of 32C! Then gradually increased the maximum each day with 36C showing yesterday lunchtime. (Posted in here)

Great stuff from everyone in here this last ten days or so - really enjoyed the build up to this plume! We have got the wonderful high temperature...bring on the spectacular thunderstorms now!  (Keep an eye on the sky - who knows what will pop up!)

Have a good weekend everyone!

Even that has been a touch too low. Just shy of 38’C at Heathrow.

[Fourty Point Three Degrees]

37.8C at heathrow?? In that case I think its worth mentioning the July 2006 record in Wisley which was 36.5 has been broken three times in just five years, 2015 (36.7) , 2019 (38.7) and then again 2020.  Also there was speculation around the end of July 2018 that it would reach 37/38C but was cut short when the heat was pushed away too fast. 

 

[Zak M]

10 minutes ago, 38.7°C said:

37.8C at heathrow?? In that case I think its worth mentioning the July 2006 record in Wisley which was 36.5 has been broken three times in just five years, 2015 (36.7) , 2019 (38.7) and then again 2020.  Also there was speculation around the end of July 2018 that it would reach 37/38C but was cut short when the heat was pushed away too fast. 

 

Bet you were thinking about changing your name when you saw the 37.8c 

[Guest]

13 minutes ago, 38.7°C said:

37.8C at heathrow?? In that case I think its worth mentioning the July 2006 record in Wisley which was 36.5 has been broken three times in just five years, 2015 (36.7) , 2019 (38.7) and then again 2020.  Also there was speculation around the end of July 2018 that it would reach 37/38C but was cut short when the heat was pushed away too fast. 

 

That is amazing but looking that the regional breakdown there's reasonable evidence to suggest heatwaves are generally becoming shaper and more biased towards the south east. Despite the repeated recent records the last time Bournemouth officially reached 32c/90f was the day of the wisley record in 2006, 32C happened regularly in 1989/90/94/95/2003/06 here. 

[MattStoke]

3 hours ago, chapmanslade said:

Look at the time on that chart, 18.00 GMT which is 19.00 BST. Looks entirely reasonable to me

It’s the highest temperature projected for the preceding 6 hour period. The GFS temperature predictions are woeful. 6 degrees too low.

[Djdazzle]

10 minutes ago, MattStoke said:

It’s the highest temperature projected for the preceding 6 hour period. The GFS temperature predictions are woeful. 6 degrees too low.

They have always been woeful for the U.K. Not sure what they are like in other parts of the world.

Models looking good for more plumes - hoping for a cracking12z suite.

[chapmanslade]

11 minutes ago, MattStoke said:

It’s the highest temperature projected for the preceding 6 hour period. The GFS temperature predictions are woeful. 6 degrees too low.

Really ? It says valid 18.00GMT with nothing about the last 6 hours ???

[Djdazzle]

2 minutes ago, chapmanslade said:

Really ? It says valid 18.00GMT with nothing about the last 6 hours ???

It does, but it’s always worked that way.

[MattStoke]

1 minute ago, chapmanslade said:

Really ? It says valid 18.00GMT with nothing about the last 6 hours ???

It’s the way all computer models work. The temperature they give is the maximum for the preceding interval rather than for that precise period of time. I think it’s for the preceding 6 hours but could be 3 hours. Either way, it only showed a high of 32’C today, and widely lower than that. About 6 degrees off across the board.