Storm Forecast
Valid: Tue 04 Jun 2024 06:00 to Wed 05 Jun 2024 06:00 UTC
Issued: Tue 04 Jun 2024 07:25
Forecaster: GATZEN

A level 2 was issued across eastern Romania, Moldova, and central Ukraine for large hail and severe wind gusts.

A level 1 was issued across western Ukraine and western Romania for extreme rainfall and large hail.

A level 1 was issued across Bulgaria, eastern Romania, and southern Ukraine for large or very large hail and severe wind gusts.

A level 1 was issued across northern Algeria for large hail and severe wind gusts.

A level 1 was issued across north-western Russia for extreme rainfall.

A level 1 was issued across southern Russia for large hail.

A level 1 was issued across north-western Turkey for large hail.

SYNOPSIS

Blocking regime across Europe further weakens as a polar trough enters north-western Europe. Low geopotential across southern Europe merges to the westerly flow and continues to progress north-east. Several vort-maxima along the southern branch of the jet will provide an active weather pattern.

DISCUSSION

Romania into Ukraine

A short-wave trough crosses the region during the day. Cyclogenesis is expected over the western Ukraine with a cold front progressing eastward. Prefrontal air mass is moist and unstable, with CAPE in the order of 800 to 2000 J/kg. Rather long hodographs with DLS aroung 15 m/s are in place that are mostly straight in the north and curved in the south due to warm air advection.

Storms are expected to develop or re-intensify during the day. Highest potential for severe is in the level 2 area. Initial storms will be capable of producing very large hail especially in the southern portions. During the period, storms are forecast to cluster and merge into convective systems, with an incrasing threat of severe wind gusts. In the evening, these storms will gradually become elevated while traveling into northern Ukraine.

Along the southern parts of Romania and across Bulgaria, potential for initiation is lower due to dry air masses around the LFC and less pronounced forcing. However, due to a favorable CAPE shear overlap, storms that form will become supercells, capable of producing very large hail and severe wind gusts. As these storms move east, they are affected by the sea breeze front and weaken.

Northern Algeria

A short-wave trough enters the area, associated with increased potential of convection initiation. Due to high CAPE and strong shear, supercells are expected, capable of very large hail and severe wind gusts.

Northern Italy, southern Austria, northern Slovenia

A short-wave trough crosses the region, providing some QG forcing. In a moist, slightly unstable environment, diurnally driven storms are expected. These will not move in weak flow, producing local flash floods.

Russia

Ahead of a progresing short-wave trough and low pressure system, slow moving storms in skinny CAPe profiles will promote and extreme rainfall threat. Over southern Russia, stronger vertical wind shear will allow for better organized storms capable of local large hail.

Northwestern Turkey

A marginal level 1 was issued for large hail. Even though CAPE is limited, and shear is weak, high cloud bases can support a few wide and sufficiently strong updrafts for marginally hail.