Storm Forecast
Valid: Thu 10 Jun 2021 06:00 to Fri 11 Jun 2021 06:00 UTC
Issued: Wed 09 Jun 2021 22:50
Forecaster: GATZEN

A level 1 was issued across eastern Turkey and surroundings mainly for large hail and severe wind gusts.

A level 1 was issued across Ukraine, south-western Russia, southern Belarus and Moldova for extreme rainfall.

A level 1 was issued across south-east Sweden for extreme rainfall.

A level 1 was issued across eastern France, southern central Germany, and north-western Czechia for extreme rainfall.

A level 1 was issued across Bosnia and Herzegovina for extreme rainfall.

A level 1 was issued across southern Italy for extreme rainfall.

SYNOPSIS and DISCUSSION

Weak mid-level geopotential gradients are present across Europe with low geopotential across eastern Europe and a ridge over western Europe. Northerly low-level winds have pushed hot and well-mixed air masses far south, and steep mid-level lapse rates are only located over high terrain of Iberia, Turkey, Caucasus, and Alps. Areas of convectively mixed air masses are present along a former frontal zone over Germany and beneath mid-level trough centers across the Ukraine and southern Italy.

Storms are expected to develop over a widespread area given rich low-level moisture, strong diurnal heating and weak CIN. Degree of organization will be mostly low due to weak vertical wind shear. Slow-moving storms pose a threat of extreme rainfall and local flash floods. The highlighted level 1 areas concentrate on environments with lower LCLs and higher warm cloud depths, and skinny CAPE profiles favorable for heavy rain.

Additionally, pulse storms are not ruled out and a few large hail and severe wind reports are not excluded. Locally, non-mesocyclonic tornadoes are also possible, in particular along local boundaries such as land-sea-breeze convergence zones.

Across eastern Turkey and surroundings, thunderstorms are expected to develop over the high terrain in a well-mixed air mass with rather deep inverted v-profiles. With 15 to 20 m/s deep-layer vertical wind shear, these storms will also habe a better potential to organize into multi- and supercells. Locally, severe wind gusts are the main threat. Additionally, large hail is forecast.