Mesoscale Discussion
Valid: Fri 21 Jul 2023 12:00 to Fri 21 Jul 2023 16:00 UTC
Issued: Fri 21 Jul 2023 12:10
Forecaster: GROENEMEIJER/PUCIK

*** Risk of severe wind gusts and large hail increasing across western Croatia, temporarily reducing across Veneto after passage of current line of storms. Lower wind risk further North ***

Supercell storms across the Veneto region in Northeastern Italy with a history of producing large hail and a tornado are moving towards the east-southeast, reaching Istria around 14 UTC. Convection-allowing models suggest they will gradually transition into a linear mode with a risk of severe, and possibly extreme, wind gusts. How quickly this transition will take place is not entirely certain, but a considerable risk of severe winds as well as large hail will develop across western Croatia in the next hour or two, before the storm system continues eastward into northern Bosnia, adjacent central Croatia, and northern Dalmatia.

Across Veneto, the risk of an isolated storm will not entirely disappear, but the probability of severe weather will, at least temporarily go down.

Across Friuli, Carinthia, southern Styria, Slovenia, and north-Central Croatia, early convection has cooled down the air-mass considerably, reducing the risk of severe winds compared to the areas further to the south. That said, a few supercells with large hail, heavy rainfall will occur. It is thinkable that an isolated tornado may develop in this region as well as hodographs are, locally, marginally supportive for this to happen.