Storm Forecast
Valid: Thu 30 Apr 2020 06:00 to Fri 01 May 2020 06:00 UTC
Issued: Thu 30 Apr 2020 07:59
Forecaster: GATZEN

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

SYNOPSIS

A west European trough will slowly progress eastwards, with mid-level vorticity lobes affecting especially northern France, northern Germany, and northern Italy. The delta of a strong mid-level jet is across Central and east Europe, with a trough moving into the east Mediterranean and a ridge across the Baltic Sea. At lower levels, a frontal boundary is present across eastern Europe, where steep lapse rates overlap with rich low-level moisture.

Other regions will see mostly marginal CAPE, what limits the severe potential.

DISCUSSION

Northern Italy

Some CAPE can build to the south of the Alps given some low-level moisture and steepening lapse rates ahead of the approaching mid-level vorticity maximum. MLCAPE will be around or slightly above 200 J/kg. Storms are forecast in the afternoon to form near the Alps. Strong deep layer vertical wind shear around 20 m/s with locally curved hodographs will support some supercells, capable of large hail and severe wind gusts. Locally, flash flooding is not ruled out. Storms will spread east and may later re-develop across the north Adriatic Sea, where they will be more elevated due to the colder boundary layer.

France, Germany, Benelux, England

Thunderstorms are likely to form in a strongly sheared environment. Marginal MLCAPE mostly below 200 J/kg will limit the severe potential. However, some areas will see also higher CAPE and more intense storms. Due to long and mostly straight hodographs, multicells and splitting storms are forecast. Some large hail and severe wind gusts are forecast. Coverage is still not sufficient foor a level 1, though. Additionally, potential of flash floods is weak due to fast storm movement.

Ukraine, Modolva, Romania, Bulgaria, western Turkey, Greece

Several storms are forecast along the frontal boundary today. Weak vertical wind shear will result in disorganized clusters of storms. Locally, large hail will occur with the stronger storms. Main severe potential is local flash flooding due to the slow storm motion and skinny CAPE profiles. Overall potential is too marginal for a level 1 at this time.

Syria and middle east

Some local storms are forecast over the mountains today, where marginal CAPE and weak wind shear will lit severe potential. However, storms that move into the low lands or develop across these will have a potential of severe wind gusts given inverted-v profiles.