Storm Forecast
Valid: Thu 20 Jun 2024 06:00 to Fri 21 Jun 2024 06:00 UTC
Issued: Wed 19 Jun 2024 21:48
Forecaster: GATZEN

A level 3 was issued across southern Germany for very large hail and severe wind gusts.

A level 2 was issued across the Alpine area for large hail and severe wind gusts.

A level 2 was issued across western Russia and eastern Ukraine for severe wind gusts.

A level 2 was issued across the Caucasus for large hail.

A level 1 was issued across southern Turkey for severe wind gusts and large hail.

A level 1 was issued across north-eastern Spain for large hail and heavy precipitation.

SYNOPSIS

Hot air and high geopotential across the Mediterranean is surrounded by a strong mid-level jet. An embedded, sharp short-wave trough curves around the ridge and digs across south-western Russia, associated with a cold front progessing south-east. Another trough is parked across Iberia and slowly lifts into France.

DISCUSSION

South-eastern Bavaria

A moist air mass has spread south towards the Alps ahead of a frontal boundary, overlapping with a plume of steep lapse rates. Dependent on diurnal heatin that is uncertain due Saharan dust spreading across the Alps, 2-3k MLCAPE is possible. Convection initiation is expected to be isolated due to subtle forcing by warm air advection and upslope flow along the Alps. In a strongly-sheared environment (25 m/s DLS and 15 m/s 0-3 km shear), supercells are forecast that travel east along the Alps. Very large or even giant hail is not ruled out with these cells. Additinally, severe wind gusts are forecast. Main uncertainty is the blocked sunlight by dust and mid- or high-level clouds.

Eastern Alps, northern Italy, western Alps

A moist and unstable air mass is expected across large portions of the Alps. Diurnal heating is uncertain due to dust and assitiated cloudiness. However, models expect convection initiation during the day in high CAPE and strong vertical wind shear. Supercells are forecast as primary mode with large or very large hail. Severe wind gusts are also forecast, along with locally heavy precipitation.

North-eastern Spain

Within the trough, diurnally-driven storms are forecast. Limited effective shear and CAPE will also limit severe potential. Marginally severe hail is expected with the stronger storms, as well as heavy precipitation.

Western Russia and eastern Ukraine

A well-mixed air mass with inverted-v profiles develops ahead of the advancing cold front and sharp mid-level trough. A rather brief overlap of better low-level moisture and strong 0-3 km shear around 15 m/s develops along the front. Storms will likely cluster along the front capable of producing high wind gusts.

Caucasus

Storms across the mountains form in rather fat CAPE profiles, overlapping with 15 to 20 m/s DLS. Supercells are forecast capable of large hail and severe wind gusts.

Southern Turkey

Storms are expected over the mountains. Inverted-v profiles are present and some severe wind gusts are forecast. In the level 1 region, also large hail is expected.