Valid: Mon 21 Oct 2019 06:00 to Tue 22 Oct 2019 06:00 UTC
Issued: Mon 21 Oct 2019 02:27
Forecaster: VAN DER VELDE
A level 2 was issued for Mallorca mainly for excessive rainfall, large hail, tornadoes and severe wind gusts.
A level 1 was issued across SE France and NW Italy mainly for isolated excessive rainfall.
SYNOPSIS / DISCUSSION
A low pressure system associated with a large amplitude upper wave over western Europe is cutting off and intensifying over the Iberian Peninsula. The cold front has stalled over the western Mediterranean and produces thunderstorms over SE France, Corsica and NW Italy. Upslope flow of moist Mediterranean air can feed thunderstorms which may become quite persistent in some locations, producing heavy rainfall.
Significant mid level cold air advection around the Iberian Peninsula and westward warm air advection by African low generates a tightening thermal gradient under the southwesterly jet meeting the negatively tilting trough coming out of Morocco. This generates a rapidly deeping surface low and frontal wave over the southwestern Mediterranean early on Tuesday, reaching the Balearic Islands likely before 06Z with 1000 J/kg CAPE and strong forcing allowing thunderstorms to form, in an environment of 30 m/s DLS and 300-450 m2/s2 0-3 km SREH. This permits excessive rain as well as large hail, tornadoes and severe wind gusts.