590+ dam air and extreme heat in Southern Europe

[Summer8906]

Quick question, based on model runs but started a new thread so as not to make the model thread go too OT.

I note that vast areas of southern and even central Europe are showing deep red colours, approximating to 590+ DAM air, for the week of July 10th on the GFS, particularly the 06z but also the 00z and yesterday's 18z, setting in around July 11 and persisting seemingly for at least a week.

Getting concerned about this as I am off there (Greece specifically) in about a week and, while I dislike the current cool, dull weather in the UK, don't really want extreme heat either.

Does it seem likely that they are likely to see an extreme, historical heatwave of the August 2021 or August 1987 type, with temps close to 40c every day for about a week? Does 590+ air (the deep red colours) on GFS runs always mean extreme heat?

I note that the BBC long range forecast thankfully doesn't agree, with more moderate temps of 32-34c suggested for that week:

Thessaloníki - BBC Weather

WWW.BBC.CO.UK

---

14-day weather forecast for Thessaloníki.

I'm concerned as, looking back at the archives from last summer, when it was hot but not silly-hot there (30-34 typical max), the deep red colours barely made an appearance on the archive charts throughout July and August.

On the other hand there are cases when the deep red colours have made it to the UK, but without extreme temps here.

One thing's for certain, this July is certainly panning out very different to many long range forecasts which suggested warm for northern Europe and (relatively) cool, though still warm by UK standards, towards the southeast.

Edited July 2, 2023 by Summer8906

[WeatherArc]

Going off the 12Z GFS i think you should be fine, the extreme heat seems to stay mostly in North Africa and Central Med. Looks like daily temps will peak around 35-38 degrees degrees so high but nothing crazy hot like 2021, i'm not seeing any continuous days of 40+ at the moment.

However, at the end of the run (around the 14th) some hot uppers begin to be advected towards Greece

So probs looking at temps peaking around 40 for 2-3 days. 

Like i said before, not seeing anything reminiscent of the 2021 heatwave, that was caused by a high pressure 'heat dome' sitting over the country for weeks and there's no sign of that.

The deep red 590+ air doesn't always mean hot conditions, someone can probably explain it way better than me but its to do with air pressure, deep reds represent stronger pressure and therefore drier conditions. I find it's better to look at the 850 temp chart as you can see how warm the air mass being advected above is, just remember that the temp you see won't be the one on the surface as factors such as soil moisture may affect the translation downwards.

 

Edited July 2, 2023 by WeatherArc

[WeatherArc]

For some reference, this is what the 850 temp chart looked like last year when we hit 40 degrees.

[Summer8906]

9 hours ago, WeatherArc said:

Going off the 12Z GFS i think you should be fine, the extreme heat seems to stay mostly in North Africa and Central Med. Looks like daily temps will peak around 35-38 degrees degrees so high but nothing crazy hot like 2021, i'm not seeing any continuous days of 40+ at the moment.

However, at the end of the run (around the 14th) some hot uppers begin to be advected towards Greece

So probs looking at temps peaking around 40 for 2-3 days. 

Like i said before, not seeing anything reminiscent of the 2021 heatwave, that was caused by a high pressure 'heat dome' sitting over the country for weeks and there's no sign of that.

The deep red 590+ air doesn't always mean hot conditions, someone can probably explain it way better than me but its to do with air pressure, deep reds represent stronger pressure and therefore drier conditions. I find it's better to look at the 850 temp chart as you can see how warm the air mass being advected above is, just remember that the temp you see won't be the one on the surface as factors such as soil moisture may affect the translation downwards.

 

Many thanks for that. On that weather map (the one that has some 40s) I see a much more comfortable 31 at Thessaloniki, which is close to where I'm heading. I remember Larisa got a 40 last year (Larisa seems to be very prone to extreme heat) but where I was the temps were comfortable.

Thanks also for the explanation of the deep red and that it doesn't necessarily mean extreme heat.

[WeatherArc]

11 hours ago, Summer8906 said:

Many thanks for that. On that weather map (the one that has some 40s) I see a much more comfortable 31 at Thessaloniki, which is close to where I'm heading. I remember Larisa got a 40 last year (Larisa seems to be very prone to extreme heat) but where I was the temps were comfortable.

Thanks also for the explanation of the deep red and that it doesn't necessarily mean extreme heat.

No worries, Enjoy Greece