Storm Forecast
Valid: Tue 02 Aug 2016 06:00 to Wed 03 Aug 2016 06:00 UTC
Issued: Mon 01 Aug 2016 21:29
Forecaster: DAFIS

A level 2 was issued for parts of Russia,Belarus and Ukraine mainly for severe wind gusts, large hail and tornadoes.

A level 1 was issued for parts of Russia, Belarus, Ukraine and Moldova mainly for large hail or large amounts of small hail, severe wind gusts and excessive precipitation.

A level 1 was issued for N Poland and Baltic States mainly for large hail and severe wind gusts.

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

SYNOPSIS

A broad low pressure system is found over Scandinavia and another vortex is approaching the British Isles from the west. A mid level trough with a neutral (at first) and then negatively tilted axis over Poland and the Baltic States during this outlook, assisting some lift over this region. The main feature during Tuesday will be a low level cold front that crosses the large level 1 and 2 areas in East Europe. A more complex frontal activity is forecast in NW Europe but stable conditions exclude DMC. In South Italy, Balkans and NW Turkey, moist PBL and steep mid level lapse rates create a favorable environment for thunderstorm activity with or without severe phenomena.

DISCUSSION

... Russia,Belarus and Ukraine ...
Ongoing thunderstorm activity along a convergence line over this area will assist the moistening and destabilizing of the PBL. GFS MLCAPE values exceed 2000 J/kg during the afternoon, when we expect all kinds of severe threats. Despite the lack of strong DLS, this environment contains Delta - theta-e values in the range of 16-20 K which may lead in some microburst events, through evaporation cooling of precipitation masses. For the level 2 area, we expect also one or two tornadoes as LLS overlaps with decent SBCAPE and LCL values are below 1000m thanks to cold air advection. In the northern parts of level 1, in Russia the main threat will be excessive rainfall and microbursts as the load of PW is much higher than the surroundings and in the southern parts, in Ukraine - Moldova and N Romania, very steep lapse rates that overlap with MLCAPE 1-2 kJ/kg can easily produce large hail.

... N Poland and Baltic States ...
The area lies under the lower right side of the main axis of the trough, where PVA signals are significant and 15-18 m/s DLS overlap with 600 - 800 J/kg MLCAPE. These ingredients along with rather mild mixing ratios in the PBL could pose a threat for large hail (up to 2cm) and severe wind gust events ( due to dry low levels) in case of storm clustering.

... NW Turkey ....
Storm initiation will be difficult by the lack of upper level lift, however GFS suggests that the advection of moist air masses from the north, enhanced by local steep topography, could result in CI after 15z and during the night. In the morning DLS exceeds 20 m/s, gradually decreasing to 10-15 m/s, overlapping with 1000 J/kg MLCAPE. Also N Greece, FYROM and West Bulgaria may experience one or two large hail events due to steep mid level lapse rates but CAPE and DLS values are not very promising.