There are some quite consistent early warning signs for what would be a historic, probably record breaking and certainly dangerous heat dome forming over the central Med from Tunisia through Italy up to the Balkans, starting this weekend, peaking the following weekend and lasting until at least early July.
Data based on GFS output but a similar pattern is showing in ECM, albeit with a few nuances. It's been showing up for a number of runs in a row which makes me fairly confident there is a real risk here.
We're looking at a stuck jet stream pattern with a trough over Ireland and strong and persistent ridging in the central Med. Here's how it develops synoptically:
1. The subtropical jet pumps up, driven by troughing in the North Atlantic, and starts to arc over Italy:
2. A (rare) summer version of a Bartlett / Euro high develops over the Alps, extending unusually high pressure over the central Med which would usually be hovering around 1010-1015hPa after the solstice
3. This drags up VERY hot Saharan air from Algeria and Tunisia, and it then stays there for days and days, slowly spreading North-Eastwards towards the Balkans.
The intense heat starts early next week in Tunisia, Sicily, Sardinia and the Mezzogiorno.
But it really gets going further North later in the week. The daytime values are frightening, e.g. 45C in the Po Valley, Inland Sardinia, Serbia (peaking at 46C the next day)
Parts of Southern Italy reach >40C daily for 14 days (and are still going at the end of the run).
Night minima widely from 27-30C in coastal areas too, which is murderous:
This is one to watch. To avoid this we need the jet to flatten and ridge a little over the UK and to our North East, which will bring us better weather and suppress the heat dome in the Med too.
Edited by user
30 June 2022 12:48:58
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Reason: Not specified
Brockley, South East London 30m asl