Isolated supercells in a potentially tornadic setup in NE Italy – October 10, 2013

Several isolated supercells formed prefrontally in NE Veneto, Italy in the late afternoon and evening of October 10, 2013. The storms formed on a surface convergence just south of the southern Alpine flank

Photographs from storm chaser Fabio Veneziano clearly show supercellular structure of the storm with a distinct RFD cut/clear slot.

Isolated supercell north of Treviso, Oct 10, 18:40 CEST. Image credit: Fabio Veneziano

Conditions in E Veneto and Friuli were favourable for formation of tornadic supercells, particularly in the southern part where (backing) surface winds reached 40 – 50 km/h, sustained, and CAPE reached 1500 – 2000 J/kg, dropping off quite sharply towards the north. High low level lapse rates were present and LCLs in 300 – 500 m range. A 30 – 40 kt mid level SW jet was present. Any supercell that formed in the south of the region was expected to have a high tornadic potential.

Surface wind in Friuli, Oct 10, 19:00 CEST. Source: OSMER FVG.

OSMER Fossalon radar image, Oct 10, 19:00 CEST. Two isolated supercells in NE Veneto. Source: OSMER FVG.

ARPAV-CMT Monte Grande radar image, Oct 10, 19:00 CEST. Two isolated supercells in NE Veneto. Supercell photographed by Fabio Veneziano is marked by the circle. Source: ARPAV-CMT / Fabio Veneziano.

No supercells formed in the south, all development remained confined to the less favourable area in the north, near the Alpine flank. No reports of possible tornadoes have appeared.