Storm Forecast
Valid: Thu 18 Oct 2018 06:00 to Fri 19 Oct 2018 06:00 UTC
Issued: Thu 18 Oct 2018 05:37
Forecaster: GATZEN

A level 2 was issued for parts of the west Mediterranean including parts of eastern Spain, the Balearic Islands, southern Sardinia, and Sicily mainly for excessive precipitation and to a lesser extent tornadoes.

A level 2 was issued for the Mediterranean south of Sicily mainly for large hail, excessive precipitation and to a lesser extent tronadoes.

A level 1 was issued for southern and eastern Spain and the west Mediterranean mainly for excessive precipitation and tornadoes.

SYNOPSIS

To the south of the polar jett hat affects northern Europe with several progressive short-wave troughs, weak mid-level flow is present over most of Europe. A weak cut-off trough centered over the Czech Republic is associated with steep lapse rates over eastern Europe that overlap with rather rich moisture over the eastern Alps to result in weak diurnal CAPE. Main convective activity, however, goes on across the central and west Mediterranean. A lifting trough over Tunisia and a digging cut-off over Morocco cause a south-easterly flow, associated with warm air advection from the south Mediterranean towards the Iberian Peninsula.

DISCUSSION

Tunisia, Sicily, and surroundings

Latest observations indicate an MCS slowly leaving Tunisia northward, progressing towards Sicily. It is expected to continue in a highly unstable air mass with CAPE in the order of 2500 J/kg and strong westerly 0-3 km vertical wind shear around 15 m/s. Long hodographs and large CAPE in the mixed layer region of the clouds support a potential of large hail. Additionally, excessive rain is likely. Although low-level shear is not too strong, a tornado is not ruled out given favourably curved low-level hodographs south of Sicily.

West Mediterranean and eastern Spain

In a moist air mass with skinny CAPE profiles and weak flow, warm air advection is expected through-out the period. Main potential of convective storms is forecast along a convergence line from the south of Sicily to the south of Sardinia across the Balearic Islands towards eastern Spain. Excessive rain and flooding are the main threat. Additionally, waterspouts will be possible in the weakly-sheared environment.