Model Output Discussion - Autumn arrives

[Man With Beard]

31 minutes ago, markw2680 said:

Whilst I agree we all like to discuss extremes and that but they are always pretty much a week away and (normally) get watered down or even pretty much disappear. Yes it will pretty much be hot next weekend but this coming week will be pretty hot so not really sure why we are all so fixed on next weekend personally. Let’s enjoy what’s in front of us rather than be fixed on stuff that will probably end up not much hotter than the usual hot uk spell. Just my thoughts 

It's true hot spells get watered down sometimes, but it doesn't seem to be like winter when almost everything gets watered down: hot spells sometimes verify and even upgrade!

We'll just have to wait and see - and enjoy the coming week!

[Polar Maritime]

Many many posts are more suited to the summer thread and not discussing what the models are actually showing but everything else around that... These posts belong in the summer thread. I'm not saying it's not good discussion, But let's please use the relevant threads that are open for this..

Very interesting times ahead

Edited July 10, 2022 by Polar Maritime

[chrisbell-nottheweatherman]

51 minutes ago, Geordiesnow said:

Funny how when we had those GFS runs people were hoping it would "downgrade" and when less hot temperatures are modelled its being described as a "poor" run. 

If its records your after then I would say we gone slightly backwards on that potential but the devil in the details will still alter. A record has never been set in stone and its still less than a 50% chance imo but the potential has not gone. 

Subtle differences will make a huge difference down the line. 

Yes, this.  Earlier today we were saying that 42C was dangerous and a downgrade was needed for the sake of people's health, now members are complaining because one output shows that exact downgrade. 

[A Face like Thunder]

Nick Miller on the Countryfile forecast for the week ahead seemed to be hedging his bets on next weekend, as well he might at this stage.  So, as predicted, hot tomorrow, cooling down from the north on Tuesday and temperatures rising again towards the weekend. It was noticeable that Nick had the 2019 record to hand with the suggestion that it could be broken next weekend, no more than that.

[bluearmy]

30 minutes ago, MattStoke said:

With 24’C+ 850hpa temperatures and very light southerly winds, the ECM must have a lot of cloud cover to only gives highs in the low to mid thirties.

We don’t have s winds when we have those uppers - we have a flow off the n sea. Probably Sunday night is ideal but it’s night! 

[Climate Man]

1 minute ago, chrisbell-nottheweatherman said:

Yes, this.  Earlier today we were saying that 42C was dangerous and a downgrade was needed for the sake of people's health, now members are complaining because one output shows that exact downgrade. 

A huge variable here may not be picked up by the output and that is the effect of the dry ground. Local factors will also have a huge bearing on whether a record is achieved. 

Always "easier" to backtrack from these extremes as it is when very cold temperatures are modelled- simply because there is only one way for variation to go when at the limit. 

[Kentspur]

2 hours ago, Roger J Smith said:

Another theme developing is the increasing potential for severe thunderstorms on Tuesday 19th, mainly in southern England, if the Iberian low takes that track through the Channel. London definitely included in that risk zone. My take is that the 12z GFS is just as extreme broadly speaking but when you spread out the heat over a larger portion of the UK it allows stronger sea breeze influences which may be why the southeast gets knocked down from 42 to 37 or thereabouts. It may be an overcorrection, the marine influence would only extend inland 10-20 miles at most. 

Could somebody perhaps post what is considered to be the all-time UK highest temperature? I have a distant memory of reading that it was 100F in July 1868 (38.2 C) somewhere in Kent. Has that been (a) verified or (b) broken since? 

Sods law if it happens on the 19th I've cancelled 2 fishing boat trips already due to storms this last 18months!! Please make it the 20th

[MattStoke]

8 minutes ago, bluearmy said:

We don’t have s winds when we have those uppers - we have a flow off the n sea. Probably Sunday night is ideal but it’s night! 

 

 

Can’t see east/north east surface winds at any point.

Edited July 10, 2022 by MattStoke

[mb018538]

5 minutes ago, MattStoke said:

 

 

Can’t see east/north east surface winds at any point.

Flow starts to change later on Sunday on the ecm. By Monday it’s from the north and then northeast.

[MattStoke]

Just now, mb018538 said:

Flow starts to change later on Sunday on the ecm. By Monday it’s from the north and then northeast.

But it has southerly winds throughout Sunday, which is when we have the highest 850hpa temperatures.

[Polar Maritime]

20 minutes ago, Polar Maritime said:

Many many posts are more suited to the summer thread and not discussing what the models are actually showing but everything else around that... These posts belong in the summer thread. I'm not saying it's not good discussion, But let's please use the relevant threads that are open for this..

Very interesting times ahead

I will just put this post here again just incase some 'reluctantly' missed it. 

[tight isobar]

Member/ supports @ ec-12 suite.. if you’re ignoring the take- members- clustering.. then you must also assume.. the model on raw/ and decipher base is a waste of meteorological time!!.. all we await is to what extension/ extreme we may come to fruition with—@ the London ones..

[Polar Maritime]

Any more off topic posts will now have to be deleted, As I've said please use the Summer thread for anything not Model output discussion. Thankyou all

[Man With Beard]

My usual flick through the ECM ensembles found we are gently close in on the details:

47 out of 51 members deliver a *raw* 33C or more at some point during the plume 

25 out of 51 members deliver a raw 36C or more (this usually means 38C plus in real terms)

 

 

[mb018538]

12 minutes ago, MattStoke said:

But it has southerly winds throughout Sunday, which is when we have the highest 850hpa temperatures.

Can only assume that as the flow on Sunday starts to veer WSW-erly through the peak afternoon heat ;from midday onwards it just takes a degree or two off the heat. Still baking hot though at 36c. Straight southerly is what we’re after all day!

[bluearmy]

13 minutes ago, MattStoke said:

 

 

Can’t see east/north east surface winds at any point.

You mentioned 24c ?

6 minutes ago, MattStoke said:

But it has southerly winds throughout Sunday, which is when we have the highest 850hpa temperatures.

sunday 14:00 with a clear surface flow off the continent 

By 20:00 it isn’t any more

I think we can trust the model to calculate the maxes ….

 Not that there is much point micro analysing a week away 

[Snowy L]

11 minutes ago, tight isobar said:

Member/ supports @ ec-12 suite.. if you’re ignoring the take- members- clustering.. then you must also assume.. the model on raw/ and decipher base is a waste of meteorological time!!.. all we await is to what extension/ extreme we may come to fruition with—@ the London ones..

Some but not many going for the peak continuing through Monday. At odds with this morning's MOGREPS where the biggest cluster went for more long lasting heat.

Edited July 10, 2022 by Snowy L

[stodge]

Evening all

MY sense looking at this evening's output the core of the plume will be over southern and central Britain on Sunday and Monday - some models call Sunday the hottest day, others go for Monday.

Certainly mid to high 30s very much on the cards for southern and eastern Britain for a couple of days.

GFS OP offers a second glancing blow for the 20c 850hpa isotherm on the following weekend but that's a very long way off.

We are of course still an eternity away in forecasting terms so a lot of detail to be resolved as the week progresses.

 

[MattStoke]

4 minutes ago, bluearmy said:

You mentioned 24c ?

sunday 14:00 with a clear surface flow off the continent 

By 20:00 it isn’t any more

I think we can trust the model to calculate the maxes ….

 Not that there is much point micro analysing a week away 

Neither of which is from the north east, like I said, unless the planet has flipped around.

Models are often off on temperatures, sometimes by several degrees.

Edited July 10, 2022 by MattStoke

[chrisbell-nottheweatherman]

13 minutes ago, tight isobar said:

Member/ supports @ ec-12 suite.. if you’re ignoring the take- members- clustering.. then you must also assume.. the model on raw/ and decipher base is a waste of meteorological time!!.. all we await is to what extension/ extreme we may come to fruition with—@ the London ones..

Sorry, I don't follow your analysis, and I'd like to be able to.  Could you possibly re-phrase, please?

[MattStoke]

Unfortunately, I’ve been told the MOGREPS ens 12z and 18z aren’t updating at the moment so we’ll have to wait for tomorrow’s 6z suite on that one.

[tight isobar]

17 minutes ago, chrisbell-nottheweatherman said:

Sorry, I don't follow your analysis, and I'd like to be able to.  Could you possibly re-phrase, please?

Well then let’s have another pop @ Chris ay! The 2m temperature ensemble - from THEE 12 model run @ ecmwf!! Are in line with the perturbed ensemble members- of high contrast clusters.. to which would support/ suggest, a high = very high temperature basis, for London.. and quite possibly a large geographical swathe around!.. to boot.. as pre- mentioned, if as even 1 model run ( that is/ has been supported by sister suites)- isn’t enough for A clarification of notable heat developments into low/ mid lying uk.. then I cannot guise.. why some want to bother with what’s biting their noses .. if you would like, a more detailed base scale prognosis/ deciphering of mine... don’t hesitate to flag it

Edited July 10, 2022 by tight isobar

[bluearmy]

27 minutes ago, MattStoke said:

Neither of which is from the north east, like I said, unless the planet has flipped around.

Models are often off on temperatures, sometimes by several degrees.

wasn’t clear on your original post that you meant Sunday 

There is quite a bit of high cloud cover through Sunday 

and as illustrated, the clean flow off the continent is cut at some point Sunday pm

Models are off on temps but we are comparing runs rather than verification 

[Geordiesnow]

5 minutes ago, bluearmy said:

wasn’t clear on your original post that you meant Sunday 

There is quite a bit of high cloud cover through Sunday 

and as illustrated, the clean flow off the continent is cut at some point Sunday pm

Models are off on temps but we are comparing runs rather than verification 

How much does high cloud affect temperature? Whilst it can be a nuisence at times to make the sunshine very hazy, I did not think it greatly affects temperatures due to it being so high in the atmosphere and thin in nature? 

[damianslaw]

Lots of posts hidden this evening, seems to be alot of general summer discussion and less focus on the models.

Ahead we have the mid week of summer, and summer seems to be playing ball coinciding with the heart of summer this year, quite similiar to last year.

A classic summer week ahead for some, in the SE if you like heat, less so further north with a cool down Tuesday - Thursday before a warm up again by the end of the week.

The end of the week sees high pressure languishing over the country, I'm not speculating on temperatures, but mid 30s highly probably in favoured SE spots,

I'm looking further ahead to the third week of  July, hard to tell what may happen - welcome thoughts, are the effects of the MJO expected to pull in much more unsettled weather? Will be needing some rain.