Model Output Discussion - Autumn arrives

[kold weather]

1 minute ago, Mark Smithy said:

So one chart is of France and the other is of the UK? 

Not quite sure what has got into a couple of people on here with this. I've posted a chart of actual 13h30 temps now in France and the GFS 17h00 max for today and can see no basis at this stage for a claim that the GFS maxima are 'over the top'

Not what I'm saying.

I'm saying temperature right now is being over done compared yo the forecasted temp for 11z. I think that's where the confusion is stemming from.

Maxes may well end locally in line with forecasts. For example I think the max temp locally in SW France did make the expected temp, but the GFS had that max over way too big of an area in the end.

Anyway I still think we are game for a 39c tomorrow, ECM is going to be too low I reckon.

[snowsummer]

16 minutes ago, Mark Smithy said:

You keep repeating this without providing any verifiable evidence. If you're going to make assertions of this kind, at least back it up with hard, proper, verified evidence i.e. model output charts vs actual verified weather station reports. Not a casual glance at a couple of distant charts, picking and choosing a time of day.

I'm not saying your evangelical zeal on this is misplaced but you're not helping your cause.

Hi. In the grand scheme of things does it really matter if the gfs is showing slightly  over, or ecm slightly  under? Its like saying theres gonna be 6inches of snow, wait  no 7 inches. Actually only 5 after all. Would still be carnage on the roads. Same with this heat. Its too hot already so .....  anyway i want to see the record broke, just to get it over with. But I'm  not particularly good at reading them charts yet, so more discussion  on the coming week after tuesday please 

[Battleground Snow]

ECM v GFS temps at this range is academic, when you have ukv, arome and arpege showing 40+

[bluearmy]

5 minutes ago, Mark Smithy said:

So one chart is of France and the other is of the UK? 

Not quite sure what has got into a couple of people on here with this. I've posted a chart of actual 13h30 temps now in France and the GFS 17h00 max for today and can see no basis at this stage for a claim that the GFS maxima are 'over the top'

You questioned that I’d cropped the charts so I posted them un cropped to satisfy your cynicism 

why are you comparing actual 13:30 French time with a forecast for pm maxes?  you surely need to wait until 5pm for that ?

[MattStoke]

3 minutes ago, Battleground Snow said:

ECM v GFS temps at this range is academic, when you have ukv, arome and arpege showing 40+

UKV in particular is very similar to the GFS which gives some confidence to their projections but they could of course both be wrong!

[Cambrian]

21 minutes ago, jon snow said:

I remember to hull and back..this from the 6z is more like to HELL and back!!!!!

 

 

Great to see your post. A tad cooler out west for Tuesday - 18 degrees on Anglesey, and at the tip of the Lleyn peninsula and Pembrokeshire.

 

[nick sussex]

Temps widely around 37c in sw France so extremely likely we’ll see 40+ by the end of the day .

Yesterday’s top temperature was recorded at Belis in the Landes at 40.7c .

 

Edited July 17, 2022 by nick sussex

[Derecho]

30 minutes ago, kold weather said:

Not what I'm saying.

I'm saying temperature right now is being over done compared yo the forecasted temp for 11z. I think that's where the confusion is stemming from.

Maxes may well end locally in line with forecasts. For example I think the max temp locally in SW France did make the expected temp, but the GFS had that max over way too big of an area in the end.

Anyway I still think we are game for a 39c tomorrow, ECM is going to be too low I reckon.

Yes it does appear temperatures on the GFS for France at the moment are too high going by the obs we currently see. Other stations which don't update live though may be hotter and I notice Bilbao in northern Spain is bang on forecast, hitting 40C.

Biscarosse in SW France currently leading the way at 38.1C, GFS perhaps warming things up a bit too quickly, though we are above the EC for the same time too.

EDIT: I can see Lagarrigue is currently at 39.6C and Douelle at 39.1C. Seems GFS is perhaps overdoing the widespread extent of the really high maxima but is close overall to the absolute maximum.

Edited July 17, 2022 by Quicksilver1989

[Cambrian]

High summer is surely upon us and what a great summer it has been so far. For those who are bold enough to countenance the post-heatwave models, it seems that once we get through the heat, Old Mother Ocean has nothing much in the cupboard leading up to the end of the month other than the most gentle and intermittent of influences from where we normally get our weather. 

From the 6z GFS operational run, mid-latitude positive height anomalies at day 7 stretch not just across the full breadth of the pond, but pretty much from the Pacific coast, through North America all the way to Russia, the Ukraine and down into Saudi. The jet stream struggles to get above 140 mph anywhere and is in tatters. 

 

Looking at the mean height anomalies over the Northern Hemisphere through to day 10, it’s striking that the positive height anomalies are so much more abundant than the negative height anomalies, at both mid and high latitudes, 0z GEM, 6z GFS, 0z ECM

  

so the hemispheric heights overall are consistently above average for the time of year, this has been the case for all the main models run after run. To me, it’s an indication of just how much more heat there is in the top part of the planet this summer. 

A summer of records about to be broken to the extent that it fundamentally changes our perceptions of what summer in these islands can bring. This year’s high summer in the Northern Hemisphere really is a very high summer. 

[Mark Smithy]

So we have already hit 30C today at 13h00. GFS temps win again over ECM!

Interestingly the current hot spot in the UK is at RM Chivenor which leads back to the discussion earlier about the models showing 39C for the same area tomorrow. Foehn effect with the long draw from the sea up and over Dartmoor / Exmoor? I think right now you might not bet against a very high temp there tomorrow.

 

[NorthantsSnow]

Regardless of whether we get the fairly widespread area of 40c the GFS is predicting on Tues, it will certainly be reached in places. I think we can say that for certain now.

So for me the GFS emerges with an awful lot of credit for picking it up so early and sticking with the idea. I know it initially had Sunday as the hottest day, but it's still been remarkably consistent for the most part and handled this current setup better than the other leading models.

[Mark Smithy]

25 minutes ago, nick sussex said:

Temps widely around 37c in sw France so extremely likely we’ll see 40+ by the end of the day .

Yesterday’s top temperature was recorded at Belis in the Landes at 40.7c .

 

Yep which means the GFS has it exactly right.

And as for the zulu time issue. It's currently 12.30 zulu time, so GFS is going to be even more correct with its maxima in France today. 

[Mark Smithy]

38 minutes ago, bluearmy said:

 

why are you comparing actual 13:30 French time with a forecast for pm maxes?  you surely need to wait until 5pm for that ?

Oh merely to show that the GFS is going to have their France maxima spot on for today. As those are the temps now then by the time 17h00 zulu is reached (19h00 French local) then if anything GFS will have under-estimated them not the other way around. 

Here as a reminder are their model forecast maxima for today. I see nothing in the current evidence to suggest these won't be reached.

[bluearmy]

ec 06z is a degree cooler for Tuesday with the clearance a bit faster than the 00z run 

[MattStoke]

It’s difficult to verify the accuracy of model temperature projections anyway as higher (or lower) temperatures might occur where there is no weather station to record it.

If a tree falls but no-one is around to hear it, does it still make a sound?

[legion_quest]

22 minutes ago, Cambrian said:

A summer of records about to be broken to the extent that it fundamentally changes our perceptions of what summer in these islands can bring. This year’s high summer in the Northern Hemisphere really is a very high summer. 

Do we have any idea as to why? Is there any specific reason that the jet stream is so weak this summer as opposed to previous? 

Obviously global warming and climate change, but is there anything we can point at in the charts and models to say why this summer is getting so hot? 

[cambs_ry]

Lots of hair-splitting at the moment, the heat is exhausting enough!

Anyway, the ECM is exhibiting lots of storm potential Tuesday PM for southern England, though the GFS has CAPEs of 2000+ in the north - what’s at play here?

[kold weather]

4 minutes ago, MattStoke said:

It’s difficult to verify the accuracy of model temperature projections anyway as higher (or lower) temperatures might occur where there is no weather station to record it.

If a tree falls but no-one is around to hear it, does it still make a sound?

I think this time we will have no problem verifying a record this time, I think quite considerable parts will be at 38c+ on Tuesday.

[MP-R]

4 minutes ago, legion_quest said:

Do we have any idea as to why? Is there any specific reason that the jet stream is so weak this summer as opposed to previous? 

Obviously global warming and climate change, but is there anything we can point at in the charts and models to say why this summer is getting so hot? 

The jet is rarely strong at this time of year anyway. Normally gets more organised towards mid to late August.

This continues quite a long period of mostly weak jet activity though, with only short bursts here and there.

[Liam Burge]

Would someone be able to tell me where NW gets their current temperature per town from? According to this it is 29.2c and we should be the 3rd hottest place in the country, however we aren't displayed on the Latest Temperatures?

[Frosty.]

1 hour ago, Cambrian said:

Great to see your post. A tad cooler out west for Tuesday - 18 degrees on Anglesey, and at the tip of the Lleyn peninsula and Pembrokeshire.

 

Cheers friend …I like heat, but seriously, Shirley  the 6z shows the wrong kind of heat??!    

 

 

Edited July 17, 2022 by jon snow

[phil b]

27 minutes ago, Mark Smithy said:

So we have already hit 30C today at 13h00. GFS temps win again over ECM!

Interestingly the current hot spot in the UK is at RM Chivenor which leads back to the discussion earlier about the models showing 39C for the same area tomorrow. Foehn effect with the long draw from the sea up and over Dartmoor / Exmoor? I think right now you might not bet against a very high temp there tomorrow.

 

The really warm air is moving into the south west as we speak 18C uppers approaching Chivenor

[Snowy L]

18 minutes ago, bluearmy said:

ec 06z is a degree cooler for Tuesday with the clearance a bit faster than the 00z run 

Not much really it's the ECM Vs everyone else. To show the difference, the 06z MOGREPS shows every single member going for the big decline after 5pm in London, half split about 5-7pm, the other half 9-11pm. ECM goes for 2pm, it's completely on its own.

 

 

[Mark Smithy]

Okay so looking to our south and the source of the UK's plume heat, the GFS look if anything to be under with their maxima for SW France (not so sure about further north today). 40C has already been reached there and they 'only' forecast a maximum of 41C. There are 4 more+ hours for maxima to be reached. Remember it's still only 13.15 zulu time.

 

So Tamara's point from Portugal, that the models have underestimated the maxima in this plume may well pertain for the UK Monday and Tuesday

 

[Captain Shortwave]

Fair to say the 06z GFS and ECM have if anything increased the uncertainty for Tuesday. For eastern areas the difference probably isn’t that much (Though it could be the difference between 40c or not). However western areas the difference will be much starker. Could be the difference between another very or extremely hot day and one that peaks by noon and falls rapidly through the afternoon.

For what it is worth the 09z UKV has 39c as the max tomorrow, still 42c showing towards Leeds on Tuesday.

Edited July 17, 2022 by Captain Shortwave