Storm Forecast
Valid: Tue 06 Aug 2019 06:00 to Wed 07 Aug 2019 06:00 UTC
Issued: Mon 05 Aug 2019 21:16
Forecaster: DAFIS

A level 2 was issued for parts of France ,Switzerland, N Italy, S Germany, Austria, Czech Republic and Slovakia mainly for large hail, excessive precipitation and severe convective wind gusts.

A level 1 was issued for France ,Switzerland, N Italy, S Germany, Austria, N Slovenia, Czech Republic, S Poland,Slovakia, N Hungary and W Ukraine for large hail, excessive precipitation and severe wind gusts.

A level 1 was issued for SE Sweden, NE Poland, Lithuania and Latvia mainly for large hail and severe wind gusts.

SYNOPSIS

Strong baroclinicity at the boundary where a cold air mass brought by a trough over the UK and an amplifying ridge in Central Mediterranean, leads to a strong jet-stream over West-Central Europe. A moisture flux both from the Atlantic and Mediterranean has brought important amounts of moisture over the continental Europe which along with steep lapse rates will create a favorable environment for DMC. Another interesting area for deep convection is SE Sweden and the Baltic States where a short-wave impulse will provide lift to unstable air masses.


DISCUSSION

.... France ,Switzerland, N Italy, S Germany, Austria, N Slovenia, Czech Republic, S Poland,Slovakia, N Hungary and W Ukraine ....

The south-southwesterly low-level flow at the Gulf of Lion brings very moist air masses to France and they are advected NE towards Switzerland and S Germany. More than 1.000 J/kg MLCAPE will be available in this area, overlapping with 15-20 m/s DLS and comparable 0-3km bulk shear. Some storms may quickly become supercells getting the advantage of strong environmental helicity. Some of them may even split over Switzerland and S Germany, producing all kinds of severe weather, though tornado threat is limited given the straight-line low-level hodographs with weak 0-1km shear. Nevertheless, most of the long-lasting storms will propagate east towards Austria in the afternoon where hail and severe wind gust risks are elevated enough to issue also a level-2 there.
As the trough from NW will propagate east, thunderstorms will keep forming even during the night with a decreased risk for severe weather, but local flash floods are well possible.


.... SE Sweden, NE Poland, Lithuania and Latvia ....

A plume of air masses with high theta-e is moving towards this part of the continent, where a short-wave trough is expected in the afternoon, during the maximum diurnal heating. Storms will form in an environment of about 1.000 J/kg MLCAPE and 15 m/s DLS and some of them will be capable of producing large hail and severe wind gusts.