Model Output Discussion - Autumn arrives

[Djdazzle]

8 minutes ago, Ed Stone said:

Just taken my morning look-see at the BBC app: 16 straight days at 21C or above, so most of this morning adjectives do not apply!

16 straight days above 21C is hardly noteworthy in July in southern England!

[Tim Bland]

Good news for farmers and gardeners is that there is a bit of rain Tuesday / early Weds. apart from that it’s hot / warm and dry for the foreseeable. Personally I’m happy with low 20s, but I understand the frustration for those further north!

[mountain shadow]

8 minutes ago, mhielte said:

Those two statements do not link at all. Since when does a cooler spell for the NW marry up to the potential for record temperatures further south and east?

Some massive IMBY overreactions this morning.

Not really.  If the temperature is only 16C in the North West, it indicates an Atlantic influence which is bound to curtail temperatures towards the South East. 

[Guest]

Awful ECM ensembles and ridiculously large downgrade, over 5C reduction in the mean for a week out. One of the biggest flips I can ever remember as ECM bullishly and unanimously removed the heat. Potentially big track from the Meto / BBC if this plays out. 

[Methuselah]

8 minutes ago, Djdazzle said:

16 straight days above 21C is hardly noteworthy in July in southern England!

I never said it was noteworthy, merely that it flies in the face of the usual morning time knee-jerk reactions. Maybe there's something about the 00Z run? But, come what may, the weather will do its thing, regardless.

[Guest]

1 minute ago, Ed Stone said:

I never said it was noteworthy, merely that it flies in the face of the usual morning time knee-jerk reactions. Maybe there's something about the 00Z run? But, come what may, the weather will do its thing, regardless.

But 16days of 21C is poor when last night we had 10days of 30C. 21C is guaranteed on 9 out of 10days down here in July and august and not even warm.

[seb]

My goodness. What are all these overreactions about?

As I said a few days ago, I’m sorry for the NW but there was never a sign of more than a few days of summer weather let alone a heatwave.

The rest of the country, steady as you were. That includes no rain on any model for central and eastern Southern parts for the foreseeable future (i.e. not even in FI range).

[I remember Atlantic 252]

5 minutes ago, Alderc said:

But 16days of 21C is poor when last night we had 10days of 30C. 21C is guaranteed on 9 out of 10days down here in July and august and not even warm.

Try living in the NW, horrible all week here

[Methuselah]

2 minutes ago, Alderc said:

But 16days of 21C is poor when last night we had 10days of 30C. 21C is guaranteed on 9 out of 10days down here in July and august and not even warm.

Just to clarify, I said at or above 21C. Perhaps I should have said mostly around 25C? Anyway, as I definitely did say: the weather will do whatever it does; it won't be asking the GFS for permission!

[Guest]

13 minutes ago, seb said:

My goodness. What are all these overreactions about?

As I said a few days ago, I’m sorry for the NW but there was never a sign of more than a few days of summer weather let alone a heatwave.

The rest of the country, steady as you were. That includes no rain on any model for central and eastern Southern parts for the foreseeable future (i.e. not even in FI range).

Huh? 
 

[summer blizzard]

As per the runs yesterday we see largely the same pattern. Cold front arrives midweek, Euro then builds a plume while the GFS has a one day wonder for most.

[seb]

5 minutes ago, Alderc said:

Huh? 
 

No rain southeast of Bath unless of course you want to take a GFS precip chart showing 5mm accumulated rain by the end of its run as gospel.

[Captain Shortwave]

26 minutes ago, Alderc said:

Awful ECM ensembles and ridiculously large downgrade, over 5C reduction in the mean for a week out. One of the biggest flips I can ever remember as ECM bullishly and unanimously removed the heat. Potentially big track from the Meto / BBC if this plays out. 

I wouldn’t call it a flip given the 850hpa temperatures will be dependent on the behaviour of that Azores low. The long wave pattern is fairly similar to previous days, just the low is much slower to move north (or does not at all).

However it would be nice to see a bit of homing in regarding that low, it is a big tease for driving something very hot. Fair to say expectations will need to be reigned in a little for now regarding Wednesday onwards. There is going to be a ridge building quite far north over Eastern Canada, this should allow a more defined Atlantic trough to develop, so I expect an improvement to occur during week 2.

[Frosty.]

Funnily enough, the longer term (day 10) ECMWF 0z ensemble mean is even hotter for the south / southeast than yesterdays 12z!.. …in the meantime, enjoy all the high pressure / sunshine  and very warm / hot weather during the days ahead! …apart from more  N / NW parts of the u k!    

 

Edited July 8, 2022 by jon snow

[MattStoke]

Running through the ECM ensembles, almost all bring a significant plume to the U.K. still after the cooler blip mid next week. A few of them record challenging if not record breaking.

Still needs watching.

[wimblettben]

5 minutes ago, MattStoke said:

Running through the ECM ensembles, almost all bring a significant plume to the U.K. still after the cooler blip mid next week. A few of them record challenging if not record breaking.

Still needs watching.

Yes but roughly 10 day's out again just like last week.

[Man With Beard]

Really incredible ensembles set from the ECM (I'll come to the "downgrade" in a minute!)

Difficult to say for sure but I think over half of the ensembles set get London to the 20C 850hpa line at some point, and quite a few to 25C? Mean temperature is only held back due to different timings on the arrival of the plume.

Ah, the downgrade ... this is a 36 hour bump, which is a wave of Atlantic air riding over the top of the high - pretty typical of the models to pick up on a small feature in a westerly flow late on. So it is a temporary downgrade for next Wednesday/Thursday, but it's actually a big upgrade for Saturday 16th/Sunday 17th compared with last night's 12Z set.

[Guest]

24 minutes ago, wimblettben said:

Yes but roughly 10 day's out again just like last week.

That is factually incorrect. It was the GFS that picked up the plume around the 17/18th at longer range.

It has since come into ECMs range and has been around the D10/11 range for the last couple of days. Again though, it's for the 17/18th.

 

[Staffmoorlands]

Fax charts for Tuesday suggest another hot day but the Atlantic influence not too far away. Will be interesting to see how this plays out.

[Staffmoorlands]

And this FAX chart shows why those in the North are a little disappointed so far

Sunday

[slater]

38 minutes ago, wimblettben said:

Yes but roughly 10 day's out again just like last week.

And the week before that and before that!!, feel sorry for the NW who have had an awful summer so far

[Captain Shortwave]

At this point I wouldn’t write off Wednesday in the south. The ICON 06z was a little further north than the 00z, which was a run that still delivered very warm/hot weather for central/southern England. So there is room hopefully for the models to delay that front sinking southwards. 
Let’s see how the GFS run pans out I guess. 

[Mike Poole]

35 minutes ago, Man With Beard said:

Really incredible ensembles set from the ECM (I'll come to the "downgrade" in a minute!)

Difficult to say for sure but I think over half of the ensembles set get London to the 20C 850hpa line at some point, and quite a few to 25C? Mean temperature is only held back due to different timings on the arrival of the plume.

Ah, the downgrade ... this is a 36 hour bump, which is a wave of Atlantic air riding over the top of the high - pretty typical of the models to pick up on a small feature in a westerly flow late on. So it is a temporary downgrade for next Wednesday/Thursday, but it's actually a big upgrade for Saturday 16th/Sunday 17th compared with last night's 12Z set.

That plot highlights really well the timescale of interest for the plume, i.e sometime from days 9 to 13.  So it is not surprising it is only appearing at the tail end of selected op runs like GEM and ECM that only go to T240 right at the moment.  We will know more about the likelihood of the plume event once the whole of that time window is within the 10 day range, in a couple of days time. 

[MattStoke]

52 minutes ago, wimblettben said:

Yes but roughly 10 day's out again just like last week.

ECM ensembles have always had it a few days later, around 18th, than the GFS, around 16th, which has now started pushing it back.

A slower evolution mean more prolonged too.

Edited July 8, 2022 by MattStoke

[northwestsnow]

6z looks hot across much of the country Sunday  Monday and Tuesday