Storm Forecast
Valid: Thu 29 Jul 2021 06:00 to Fri 30 Jul 2021 06:00 UTC
Issued: Thu 29 Jul 2021 00:59
Forecaster: GATZEN

A level 1 was issued across central Ukraine, south-western Ukraine, northern Romania, northern Moldova, and south-east Belarus for severe wind gusts and heavy rain.

A level 1 was issued across southern France and across the Alps for large hail and heavy rain.

A level 1 was issued across eastern Black Sea region mainly for heavy rain.

SYNOPSIS

A strong and rather zonal mid-level jet has developed between two intense progressive troughs across the British Isles and southern Scandinavia and very high geopotential across the Mediterranean. Embedded in the westerly flow, short-wave troughs travel east across southern France and the Alps as well as across the Ukraine. At lower levels, warm air across eastern Europe wraps around the Scandinavian trough. A broad frontal zone is present to the south across the Alps and southern France.

DISCUSSION

Ukraine and surrondings

A cold front will progress eastward today that is affected by QG forcing ahead of an approaching short-wave trough. The frontal lift will assist in convection initiation during the day in an environment characterized by 1000 J/kg MLCAPE and 15 m/s deep layer shear. Multicells are forecast that merge to linear MCSs in the afternoon, also supported by 10+ 0-3 km shear across S Ukraine. Severe wind gusts are forecast. Additionally, heavy rain and locally large hail is expected.

Southern France, Alps

The broad frontal boundary over this area will be inactive for most of the day, despite some remaining low-level moisture and lapse rates. However, some storms are forecast over the mountains of Massif Central and Alps in limited MLCAPE and about 15 m/s 0-6 km shear. Some multicells and also supercells are forecast, capable of large hail and heavy rain. Later in the period, additional storms are forecast due to some QG forcing and weak frontogenesis ahead of an approaching trough across France and Austria. Some heavy rain and large hail is expected.

Eastern Black Sea

Models indicate skinny CAPE and moist profiles along the sea breeze convergence and upslope flow beneath low mid-level geopotential. Local flooding is forecast with slow-moving or stationary cells.