Storm Forecast
Valid: Mon 23 Oct 2017 06:00 to Tue 24 Oct 2017 06:00 UTC
Issued: Mon 23 Oct 2017 00:25
Forecaster: VAN DER VELDE

A level 1 was issued for Adriatic and Aegean Sea coasts mainly for chances of excessive convective precipitation and tornadoes.

SYNOPSIS

Surface high pressure areas are situated over France and Scandinavia. A low pressure system is moving from the Afriatic Sea to the Aegean Sea and is associated with MLCAPE fields up to 700 J/kg. It is distributed in both the warm sector as the cold air mass. The mid level cold front precedes the cold airmass unstable air and PV anomaly by several hundred kilometers. Strong deep layer shear lies mainly between these zones. During the evening/night the cold front becomes more acitve as it reaches the Turkish west coast.

DISCUSSION

There are some zones where 10-20 m/s DLS and 100-200 m2/s2 SREH can overlap with CAPE and triggering conditions, which could allow some supercellular severe weather (hail), although under the axis of maximum shear instability and lift are weak. Higher are the chances for waterspouts over the Adriatic coasts where storm motion will be slow under the upper trough. GFS indicates that the low-level vorticity maximum will touch upon the (south)eastern Italy coastline.
Also, chances for excessive convective rain are somewhat elevated ahead of the PV maximum, where convection may be triggered on the coastline (Albania, Greece). But vertical column water vapour content is not extraordinary. It is higher over the cold front over Turkey at night, where also shear and CAPE allow mesocyclones in storms, enhancing tornado chances along with excessive rain. On the other hand, it does not look like a major event given the lack of strong CAPE and forcing.