Storm Forecast
Valid: Mon 03 Oct 2016 06:00 to Tue 04 Oct 2016 06:00 UTC
Issued: Mon 03 Oct 2016 02:10
Forecaster: VAN DER VELDE
A level 1 was issued for NE Italy, Slovenia and Croatia mainly for chances of tornadoes.
SYNOPSIS
A mid-level low causes unstable and rainy conditions over much of central Europe. Steep lapse rates are found on the west side of a cold front between southern Sweden and Slovenia. Convective cloud tops will be cold enough for electrification, but CAPE is just marginal. An occlusion will wrap around the low over Denmark and Netherlands, and finally also the cold front will move westward and become effectively a warm front as the core of the low shifts quickly toward Slovakia, starting a strong easterly advection of warm moist air over Poland and into Germany. The northern Adriatic region is prone to dynamic lifting from a shortwave PV feature at the south side of the main low, and a strong jet overlaps a region with CAPE.
DISCUSSION
...northern Adriatic region...
Ingredients for thunderstorms are found in overlap as steep lapse rates just make it to this area where low level mixing ratio allows a modest amount of CAPE, perhaps underestimated in the lee of the Alps. 0-6 km shear vectors created by the jet reach dramatic levels at 35 m/s and 0-3 km storm-relative helicity is maximized along north and northeast coasts of the Adriatic sea, over 250 mē/sē. These values support mesocyclones. But the low CAPE may well be a limiting factor for large hail and general threat, and while tornado chances are present, 0-1 km shear seems only locally enhanced. Therefore a level 1 appears sufficient.
