Storm Forecast
Valid: Tue 26 Jul 2016 06:00 to Wed 27 Jul 2016 06:00 UTC
Issued: Mon 25 Jul 2016 21:52
Forecaster: DAFIS

A level 2 was issued for parts of S Poland, Slovakia, Hungary, NE Croatia, SW Ukraine and NE Romania mainly for excessive precipitation.

A level 1 was issued for a large part of Central and East Europe mainly for excessive precipitation and large hail.

A level 1 was issued for Sweden mainly for large hail and severe wind gusts.

A level 1 was issued for SW Balkans mainly for large hail and severe wind gusts.

SYNOPSIS / DISCUSSION

The main feature visible at the upper level maps is wide meso-low over between Iceland and Norway, which is associated with many smaller disturbances, affecting mostly Norway and Sweden. Another cold bubble is found travelling from Adriatic Sea towards S Balkans were is expected to perish during Tuesday. On the surface, the cold front of the low pressure system north from the UK, will cross parts of Germany, Norway and Sweden. The biggest part of the continent will experience DMC as weak flow and very moist PBL create ideal conditions for excessive precipitation events. Mid-level lapse rates and DLS are weak almost everywhere inside the big level 1 area that we drew, but MLCAPE up to 2000 J/kg overlaps with very high PW in the range of 35-40 mm. We do not expect clustering of the storms, but single cells staying over an area could cause severe flash floods, especially in Hungary and West Ukraine. We forecast one or two large hail events in N Belarus and Russia as the PW load is less and CAPE reaches values of 2500 J/kg. Diurnal heating will be the steering mechanism of DMC but also noncturnal thunderstosms will pose a threat.

.... Sweden ....

A short-wave trough, as well as a cold front of the surface create DLS of 15-20 m/s in an unstable, moist environment. Storm mode is expected to be linear, with storms moving towards the coasts of Finland late in the afternoon - night. The main threat will be severe wind gusts and to a lesser extent large hail (up to 2cm) as a dry slot approaches and may enhance locally the instability. LLS and 0-3km bulk shear are meager and LCLs above 1000m, so tornado threat is very limited.

.... South Balkans ....

The impaired meso-low over the Adriatic as it moves towards the Balkans creates some lift, but PVA is weak and the only factor that enhances the large hail - severe wind gust threats is the steep mid-level lapse rates that overlap with MLCAPE 1 - 1.2 kJ/kg during the afternoon over the areas highlighted with level 1. The DLS decays while the center of the system crosses Albania and FYROM, but the threats remain for the aforementioned reasons. An isolated large hail event cannot be ruled out in the SE parts of Italy between 09z and 15z. Thunderstorm activity will perish after sunset.