Model Output Discussion - Autumn arrives

[kold weather]

56 minutes ago, danm said:

The average for London in mid to late July is about 24°c. 27°c is therefore about 3°c above average. Warm, but not exceptional. 

True, though the GFS 12z to be fair is a level above that as well, somewhere in the UK reaches 30c on 8 consecutive days (multiple 30c days in London as well) and no real sign of an end right out to the end, so you'd expect maybe 10+ days at that level.

It kinda reminds me of June 2018 actually, constantly very warm with little rain, though never particularly hot.

I will take that all day long, NOTHING to moan about. Just a solid summer month hopefully!

Edited July 3, 2022 by kold weather

[Staffmoorlands]

UKMO & ECM are not that good tonight - plenty of cloud this week away from the south.

ECM 192 - poor

[Frosty.]

I’m really happy with the icon 12z…indeed I would go as far as to say it’s wunderbar! … Ja Ja.. ️

 

 

[Bradley in Kent]

6 minutes ago, Alderc said:

Unremarkable mean driven by a massive spread on ensembles. Anything possible from record breaking heatwave to troughy  mctrough with the high way out west.

Yes, too much scatter for my liking, many scenarios for the wheels to come off for heat lovers, namely lows over NE Canada and Iceland not playing ball (again, for heat lovers). 

Personally, in Summer I tend to give more weight to the cooler ensembles, reverse it in Winter with the milder ensembles given our maritime climate. 

Fingers crossed we get a decent prolonged warm spell

 

[Nigelapplewhit4]

Just now, Bradley in Kent said:

Yes, too much scatter for my liking, many scenarios for the wheels to come off for heat lovers, namely lows over NE Canada and Iceland not playing ball (again, for heat lovers). 

Personally, in Summer I tend to give more weight to the cooler ensembles, reverse it in Winter with the milder ensembles given our maritime climate. 

Fingers crossed we get a decent prolonged warm spell

 

Very disappointing Met office and ECM for this week - average temperatures even below with lots of cloud. Much cloudier in Wales than i expected today. Disappointed summer lover! 

3 minutes ago, jon snow said:

I’m really happy with the icon 12z…indeed I would go as far as to say it’s wunderbar! … Ja Ja.. ️

 

 

This isnt going to happen! Trough city according to my modellling

[Guest]

11 minutes ago, Alderc said:

Unremarkable mean driven by a massive spread on ensembles. Anything possible from record breaking heatwave to troughy  mctrough with the high way out west.

 It is something to keep an eye on for sure, that scatter. Suggests the coolest members have retrogressed the high way out wet like you say, the ones nearest the LTA will have the high just to the west and keep most parts broadly settled and warm, with the hotter members having the high over the UK or to the east.

ECM relaxes the strongest 500mb heights for a time at the end of next weekend, potentially bringing the threat of cloud and a weak weather front over the top, before a rebuild further into week 2. 

[Guest]

2 minutes ago, Nigelapplewhit4 said:

Very disappointing Met office and ECM for this week - average temperatures even below with lots of cloud. Much cloudier in Wales than i expected today. Disappointed summer lover! 

This isnt going to happen! Trough city according to my modellling

Western parts do look quite cloudy for a lot of next week, but that has been known for a good while now. Hopefully we get a good build of high pressure over the UK by the end of the week 

No idea what your second sentence is on about though, as there's nothing to back up that comment, other than 'your modelling'  Care to share? 

[Staffmoorlands]

Just like winter - GFS & ICON teasing people whilst the ECM & UKMO suggest nothing to get excited about. 20c and mainly cloudy skies. 

 

 

[Radiating Dendrite]

1 minute ago, Staffmoorlands said:

Just like winter - GFS & ICON teasing people whilst the ECM & UKMO suggest nothing to get excited about. 20c and mainly cloudy skies. 

 

 

Where you live perhaps.

Looking at sunny and 26c here by the end of the week. We made 22c today and had some lovely sunshine. 

Some people need to relocate. As a northerner originally, the difference in summer between the north and SE is stark.

[mb018538]

15 minutes ago, Alderc said:

Unremarkable mean driven by a massive spread on ensembles. Anything possible from record breaking heatwave to troughy  mctrough with the high way out west.

Certainly one of the poorer set of 12z runs for a couple of days. See what the 00z runs say tomorrow. Really didn’t think we’d see the high get stuck out west once we hit the end of next week, but there’s clearly a growing chunk of ensemble members starting to show this now. If you are in the S/E/SE corner probably still pretty good and quite warm. Northern/Western areas might be seeing a cool total cloudfest at this rate and temp profiles like this:

[Frosty.]

The ECMWF 12z op doesn’t look bad to me?  

 

[Captain Shortwave]

12 minutes ago, Nigelapplewhit4 said:

Very disappointing Met office and ECM for this week - average temperatures even below with lots of cloud. Much cloudier in Wales than i expected today. Disappointed summer lover! 

This isnt going to happen! Trough city according to my modellling

The last time I checked - Murphy’s law was not a computer model.

ECM is sort of… meh thanks to the jet stream being a little further south and as such allow fronts to affect larger parts of the country. It gets a mark knocked off further for the day 10 tease. The UKMO is an odd one because I kind of don’t buy the idea of the high simply destabilising itself without much in the way of forcing to actually do this.

Anyway I think the working week is pretty set in stone and very warm in southern and eastern parts. Wednesday being the first day that 25c should be reached/surpassed.

 

 

[damianslaw]

Oh dear I can see this thread descending into a slanging match so to speak in the days ahead between heat lovers and those seeing exceptional heat, and those who prefer things average or cooler or don't foresee these exceptional extreme temps. More than I've known in this thread there seems to be a lot of focus on potential 40 degrees heat etc.. with some willing such temps to arrive..

Anyway back to reality.. the upcoming week indeed will see a marked change from recent conditions. High pressure building very strongly to our west, inching its way ever so slowly into the UK, bringing mostly settled weather away from northern parts, here patchy rain and showers order of the day and dissapointingly cloudy which will peg temps down below average. Warmth and sunshine reserved primarily for the SE quarter of the UK. As we end the week, some divergence taking place, ECM less keen on ridging heights in sufficiently, thus maintaining the same theme of much of the week, UKMO seems to be doing the same, whereas GFS unusually as it tends to be the most progressive of the three, builds heights in strongly over the country bringing widespread sunshine and warmth to all.

I'll leave things there, because we can't say for certain just where heights will eventually end up and therefore what may happen as we enter the middle of the month.

[Staffmoorlands]

3 minutes ago, damianslaw said:

northern parts, here patchy rain and showers order of the day and dissapointingly cloudy which will peg temps down below average. Warmth and sunshine reserved primarily for the SE quarter of the UK. As we end the week, some divergence taking place, ECM less keen on ridging heights in sufficiently, thus maintaining the same theme of much of the week, UKMO seems to be doing the same

Yes, away from the south east it looks very disappointing compared to how it looked only 24 hours a go!  

[TSNWK]

4 minutes ago, Staffmoorlands said:

Yes, away from the south east it looks very disappointing compared to how it looked only 24 hours a go!  

Brilliant..  winter or summer you pop your head over the wall codge! 20 years and counting from bbc snow watch.... 

I'm in the scilly isles from the 9th for a week.. south being good but also west.   I'm torn what to expect.. 

[Methuselah]

15 minutes ago, jon snow said:

The ECMWF 12z op doesn’t look bad to me?  

 

It's a game of '40 or Bust'?

[Staffmoorlands]

9 minutes ago, TSNWK said:

 

I'm in the scilly isles from the 9th for a week.. south being good but also west.   I'm torn what to expect.. 

You should be ok but MVH has just tweeted  that there is no heatwave on the way

[Lukesluckybunch]

2 minutes ago, Staffmoorlands said:

You should be ok but MVH has just tweeted  that there is no heatwave on the way

Who is MVH?

[Staffmoorlands]

10 minutes ago, Lukesluckybunch said:

Who is MVH?

Sorry, Matt Hugo. He was known as MVH years ago

[summer blizzard]

Euro has two main differences between its 0z and 12z run. 

So essentially both the 0z and 12z suggest that between days 3-10, we see 3 shortwaves pass south of Newfoundland. 

The first difference is the first low which flattens the high next weekend and simply is more progressive and already west of Iceland by day 6. With the high core to the west of the U.K., this also allows the low to send the cold front further into the U.K. even if dead. 

The second low is where the runs appear to disagree. Essentially the second low on the 0z never really phased with the Azores Low because the 0z moved it through more quickly, the 12z run however keeps this feature slow enough that it does phase and picks up the upper trough. 

There are two impacts to picking up the Azores Low. 

1) It amplifies the high to our west and first attempts to push it east over the U.K. (some ensembles achieve this) but secondly thanks to the core of the high being west of the U.K., we have a trough complex over Scandinavia and thus the 12z finally puts a used by date on our high pressure (though this may not transpire for obvious reasons). 

2) With no Azores Low to support a high close to the U.K., the next Azores Ridge is well west as the third low is south of NewFoundLand and thus with a trough over Scandinavia the high has nowhere to go but west and retrogress as the Atlantic/Scandi Trough takes over.

 

[Lukesluckybunch]

2 minutes ago, Staffmoorlands said:

Sorry, Matt Hugo. He was known as MVH years ago

Thanks...so no heatwave,probably just warm and settled a fair shout at this point?

[mb018538]

19 minutes ago, Staffmoorlands said:

You should be ok but MVH has just tweeted  that there is no heatwave on the way

AAM is struggling to rise as much as forecast even a few days ago. La Niña standing firm. Might explain why the high is really trying it’s best to build in, but just can’t get far enough eastwards without the extra momentum needed. See what the days ahead show.

Edited July 3, 2022 by mb018538

[Cambrian]

Clearly a warm spell coming up for the south and east, with the GFS always among the most bullish, but as ever, there is considerable variation between GFS operational runs in modelled temperatures. Here are the last five GFS ensembles for London.

12z yesterday - 11 successive days at 25 degrees or above, starting on the 8th, 3 days at 30 degrees or above, at the end of the run (starting on the 15th). The mean peaks just above 25 degrees on the 9th. 

18z yesterday - 10 days above 25 degrees, first one on the 7th, 7 successive days above 30 degrees at the end of the run (starting on the 13th). Mean peaks just below 25 degrees on the 11th. 

0z today - 11 successive days above 25 degrees from the 8th, 4 days above 30 degrees at the end of the run (starting on the 15th). Mean peaks just above 25 degrees on the 12th and again on the 16th.

6z today - 7 days above 25 degrees, first one on the 8th, 1 day at 30 degrees on the 13th. Mean peaks above 25 degrees on the 14th, 15th and 17th. 

Finally, 12z today - 6 days above 25 degrees, first one on the 8th, 3 days at 30 degrees, on the 16th, 18th and 19th. Mean peaks with the op at 25 degrees on the 8th, and is comfortably below that for the rest of the run. 

Some patterns emerging then :

It’s looking like a sustained warm spell,  an impressive run of days of close to or above 25 degrees, starting around the 8th. 

30+ degrees days are consistently being modelled by the op, but until now, remain at or beyond day 10, earliest start on the 13th, and these are getting pushed back run by run. They are coincident with a rise in night time minima in the later stages of the run. 

The mean does not indicate any 30+ degrees days, in fact never reaches 26 degrees on any of the runs. 

The operational runs are beginning to settle down after first signalling the potential for some very high temperatures. The op was out on its own at the high end towards the end of yesterday’s runs but the upper end is populated by a small cluster of members on today’s runs. 

Comparing the two 12z runs, the ensemble means are very similar. Today’s 12z op is running 5 degrees higher than the mean, but though 4 degrees lower than the 34 degree outing of yesterday, this outcome has at least some support from a few other members. 

It’s going to be a long warm spell of summer weather. I’m reluctant to use the H word in any case because it means different things to different people, but if the repeated operational runs are right and there are going to be suitably high temperatures for what I’m rhyming slanging as a “street rave”, I feel like I might as well go for it, get on the train to London, dye my hair pink and get out there dancing  yeah.

[I remember Atlantic 252]

1 hour ago, Staffmoorlands said:

Just like winter - GFS & ICON teasing people whilst the ECM & UKMO suggest nothing to get excited about. 20c and mainly cloudy skies. 

 

 

yes for us western areas, heat is still in FI on the GFS

[Frosty.]

Tonight’s ECMWF 12z ensemble mean looks pretty good to me, especially for the south…summery weather is coming back and hopefully it will include more of the u k than it has so far this summer, northern u k.. about time you joined in!!