Storm Forecast
Valid: Tue 24 May 2016 06:00 to Wed 25 May 2016 06:00 UTC
Issued: Mon 23 May 2016 22:20
Forecaster: DAFIS
A level 1 was issued for parts of Germany, Poland, Czech Republic, Slovakia,Ukraine, Hungary, Romania, Serbia, Croatia and Bulgaria mainly for large hail or large amounts of small hail and excessive rainfall.
A level 1 was issued for SW Russia mainly for large amounts of small hail and tornadoes.
SYNOPSIS
The longwave trough in West Europe eventually seems to break during Tuesday, with a cold drop travelling to the Balkans with a vorticity maxima over the area. Low geopotentials are also found over the British Isles and the Bay of Biscay as well in SW Russia. Locally steep lapse rates in N Spain will induce isolated storms with low lightning coverage. The most interesting areas will be near the borders of Poland, Slovakia and Czech Republic where numerical models produce near 1 - 1.2 kJ/kg of MLCAPE and an overlap of 15 - 20 m/s DLS. Same conditions are forecast for the area near the borders of Romania and Bulgaria, where a jet streak in the mid levels leads to strong DLS and steep lapse rates result in some hundreds of CAPE. Some thunderstorms may also form in Normandy, in France and in parts of Sweden and Finland.
DISCUSSION
.... Germany, Poland, Czech Republic, Slovakia,Ukraine, Hungary, Romania, Serbia, Croatia and Bulgaria ....
A stationary front in E Germany and Czech Republic is expected to trigger convection and in the absence of strong DLS storms will find it difficult to become organized, but due to locally high values of CAPE, the strongest updrafts will be still capable of producing small hail and especially in large quantities due to high PW. The best chances for the development of a MCS in the afternoon are found over E Czech Republic, Slovakia and Hungary where DLS values may exceed 20 m/s and SREH0-3km is calculated in the range of 200 - 300 mē/sē. Moist BL and high PW indicate a threat for flash floods in the area, as well as in N Romania. For the rest of the areas of level 1, large hail will be the main threat as PW values are much lower and Balkans will be at the left exit of a mid level jet streak, resulting in DLS up to 25 m/s. Storms will fade after the sunset, or at least until 00z in case of local elevated convection, except from the E Bulgaria, Moldova and the Black Sea.
.... SW Russia ....
An upper level low system is found over SW Russia, almost stationary and results in rather steep lapse rates combined with moist BL, so CAPE is forecast to exceed 500 J/kg over a large area. Low LCL heights and SREH0-1km values near 150 mē/sē show a potential for an isolated tornado event. Locally more than 1000 J/kg of CAPE and high PW may result in large amounts of small hail or up to 2 cm hail stones, but weak DLS excludes very large hail.
