Storm Forecast
Valid: Thu 27 May 2021 06:00 to Fri 28 May 2021 06:00 UTC
Issued: Thu 27 May 2021 07:03
Forecaster: GATZEN

A level 1 was issued across northern Italy for large hail.

A level 1 was issued across northern Ukraine and western Russia for heavy precipitation.

A level 1 was issued across western Turkey for severe wind gusts.

SYNOPSIS

Mid-level low geopotential covers northern and central Europe, yielding a south-westerly flow across eastern Europe and a rather strong jet over the Mediterranean. At the flank of west European ridging, a short-wave trough amplifies into the central Mediterranean and diggs into the Aegean later on. At lower levels, dry air has spread into much of Europe. A frontal boundary stretches across western Russia into the Urkaine and eastern Balkans that will be mostly quasi-stationary today.

DISCUSSION

Northern Italy

A dynamic situation evolves as the mid-level vort-max amplifies across the Alps in the evening. It will promote strong QG forcing that extens south-east during the following night. Affected air mass is expected to become slightly unstable due to remaining low-level moisture at low levels and strongly increasing lapse rates in the wake of the Alps, and models indicate MLCAPE of several 100 J/kg. Several storms are expected along the southern slopes of the Alps that will be mostly weak due to limited CAPE. However, increasing vertical wind shear makes organized storms more likely with multicells the main storm mode given about 15 m/s deep layer shear. These storms can produce large hail before convection is expected to spread south-east where shear is weaker.

Western Russia, northern Ukraine

ALong the slow-moving frontal boundary, several storms are expected to go on despite weak QG forcing. Weak shear is present and organized storms are not forecast. However, moist profiles with skinny CAPE and also quite deep warm cloud layers will promote a heavy rain threat locally.

Western Turkey

Deep inverted-v profiles evolve in response to strong diurnal heating beneath rather cool mid-level air masses. Intiation is limited due to dry profiles, and chances for storms are rather low. However, storms that form will hape a potential of producing severe wind gusts locally.