Storm Forecast
Valid: Mon 02 May 2016 06:00 to Tue 03 May 2016 06:00 UTC
Issued: Sun 01 May 2016 21:47
Forecaster: VAN DER VELDE

A level 1 was issued for western Greece and Albania mainly for chances of tornadoes and excessive precipitation.


SYNOPSIS / DISCUSSION

A ridge between southwestern Europe and southern Scandinavia separates low pressure systems over the norrthern Atlantic Ocean and the central Mediterranean Sea. The latter produces cool unstable air around Italy, with a plume of warm air ahead of a front passing over the southern Balkan. This plume contains a few hundred J/kg MLCAPE and is dynamically reinforced by a sharp negatively tilted PV lobe. Warm air advection causes veering winds with height leading to storm-relative helicity values of more than 300 m²/s² along the Greek and Albanian coastlines and a broader region of 20-30 m/s 0-6 km shear. This supports supercells which are embedded in a very moist environment with low LCL heights, which could stick in certain places and produce excessive convective precipitation. The chances for tornadogenesis are also enhanced as result of >10 m/s/km vertical shear near the surface. Isolated large hail also may occur. On the other hand, the marginal instability today should put a limit on the extent of spatial severe weather occurrence in this region, therefore a level 1 is issued.