Valid: Thu 08 Jul 2021 12:00 to Thu 08 Jul 2021 18:00 UTC
Issued: Thu 08 Jul 2021 12:33
Ahead of the pronounced mid-level vort-maximum (WV satellite image indicates a dark stripe entering NW Italy from the SW), strong QG forcing spreads across northern Italy from west to east in the afternoon. Associated cyclogenesis in the wake of the western Alps is underway with increasing easterly low-level flow across the Po valley.
A very humid low-level air mass is present with dewpoint observations up to 23 degree Celsius and a temperature around 30 degree Celsius at 12 UTC. Convection initiation is going on across the western Alps and latest satellite images indicate enhanced cumulus over northern Italy where initiation is underway.
Storms are expected to are well-organized while spreading north-east. Highest coverage is forecast along the southern foothills of the Alps, but right-moving storms can also travel across the low-lands for some time.
Strong vertical wind shear and impressive, long and curved hodographs indicate a high risk of well-organized, severe thunderstorms. Extremely severe weather including giant hail and tornadoes are forecast until 18 UTC, in particular from Lombardy to Veneto and Trentino-Alto Adige. Strong and violent tornadoes are not excluded.
After 18 UTC, storms are expected to gradually weaken while spreading farther NE and severe risk will weaken later on.