Mesoscale Discussion
Valid: Tue 17 Jun 2014 14:00 to Tue 17 Jun 2014 17:00 UTC
Issued: Tue 17 Jun 2014 14:39
Forecaster: PISTOTNIK

Convective initiation is currently concentrating along a seabreeze / upslope flow convergence over Central Italy. Coastal areas see dewpoints between 19 and 22C, which yields CAPE values between 1000 and 1500 J/kg according to the 12 UTC Brindisi and (modified) Pratica di Mare soundings.

In the Northern half of the area, deep-layer shear decreases and the background flow starts turning to the Northeast, pushing the convergence zone towards the West coast. Satellite imagery confirms some backbuilding multicells, which pose a risk of heavy rain and large hail.
Further South, storms are stationary or even moving Eastward, and deep-layer shear around 20 m/s beneath the mid-level jetstreak enables good organisation into multi- and supercells. Very low cloud bases and strong low-level shear in the sea breeze regime along the italian East coast hint at a remarkably enhanced tornado risk (refer to the recent Bari metars with 24/22C and Northeasterly surface winds around 7 m/s). Otherwise, large hail and severe wind gusts are possible, as well as flash flood producing rain in case of backbuilding.

Storms continue to travel eastward or form anew along a flow-parallel extension of this convergence line across the Southern Adriatic Sea into Northern Albania and Southern Montenegro. This pattern has already continued for 18 hours and has produced extreme flash floods in parts of Albania. This risk will still continue in the next hours. If stronger updrafts move onshore, all other kinds of severe weather are possible as well.