Storm Forecast
Valid: Tue 27 Jul 2021 06:00 to Wed 28 Jul 2021 06:00 UTC
Issued: Mon 26 Jul 2021 20:38
Forecaster: DAFIS

A level 2 was issued for parts of Italy, Slovenia, Austria, and Switzerland for large hail, severe convective wind gusts and excessive precipitation.

A level 2 was issued for parts of Belarus, Ukraine, and Poland mainly for large hail, severe convective wind gusts, and tornadoes.

A large level 1 area was issued for a large part of central and eastern Europe for large hail, severe convective wind gusts, excessive precipitation, and tornadoes.

SYNOPSIS

A strong WAA in the central Mediterranean is the result of the interaction of a deep trough in western Europe and a developing ridge in eastern Europe. Highly unstable air masses will be found near the coasts of Italy, which will feed severe storms in central Europe. Over eastern Europe, a cold front is progressively moving east, pushing warm and moist air masses which will also be the hosts of severe storms. Several additional areas will experience thunderstorms due to the abundant LL moisture and lifting mechanisms.

DISCUSSION

.... Italy, Slovenia, Austria, and Switzerland ....

Very warm and moist air masses over the central Mediterranean will be advected towards Italy and central Europe on Tue 27/07. They overlap with steep lapse rates and a strong mid-level flow. In addition to max diurnal heating, NWP models show the development of several convergence zones, thus CI in multiple areas is expected. Storms will be able to organize quickly, and some supercells will form, able to produce large hail and severe convective wind gusts while moving east. In case of MCS developments, the flash flood threat will also be high.

.... Belarus, Ukraine, and Poland ....

A cold front near the surface is expected to cross this area, during max diurnal heating. A level-2 area has been issued to highlight the areas where all the ingredients for DMC are found in the NWP models. A strong high-CAPE and DLS overlap will take place, and locally high SREH0-3km in the warm sector of the front suggest that supercells cannot be ruled out. Moreover, LL thermodynamics show an elevated potential for tornadognesis, given locally high values of SREH0-1km and
LLS. Storms will become elevated during the night and tornado threat will be limited.