Mesoscale Discussion

Mesoscale Discussion
Valid: Thu 30 Jul 2020 16:00 to Thu 30 Jul 2020 20:00 UTC
Issued: Thu 30 Jul 2020 15:45
Forecaster: PUCIK

*** Risk of damaging wind gusts will increase over northern Italy in the next few hours ***

A volatile setup is in place across northern Italy. Surface observations reveal presence of very moist airmass with dewpoints of 22 - 23 deg C, which contribute to substantial CAPE. 12 UTC Cuneo sounding looks especially concerning with large buoyancy in mid to upper troposphere and strong vertical wind shear in the bottom 3 km. At the same time, Cuneo, Milano and Capofiume profiles also reveal capping layer, which has prevented the convective initiation over lowlands so far.

As a subtle short-wave trough at 300 hPa approaches northwestern Italy in the evening hours, chances for storms spreading into lowlands will increase. As storms encounter high CAPE environment, an explosive development could follow with a development of strong cold pools. As 0-3 km shear is stronger than 0-6 km shear, line segments and bow-echoes will be more likely than supercells. Upscale growth of storms into a large MCS is also supported by convection-allowing numerical models.

This scenario would likely involve several swaths of damaging wind gusts. Wind gust risk could persist into late evening and early night hours as the MCS treks towards the Adriatic Sea.

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