Storm Forecast
Valid: Tue 26 Sep 2023 06:00 to Wed 27 Sep 2023 06:00 UTC
Issued: Mon 25 Sep 2023 22:20
Forecaster: PUCIK/KUZMENKO

A level 1 was issued across Ireland and parts of the UK mainly for severe wind gusts and tornadoes.

A level 2 was issued across Greece mainly for heavy rainfall, large hail and to the lesser degree for tornadoes.

A level 1 was issued across S Italy mainly for heavy rainfall, large hail and to the lesser degree for tornadoes.

DISCUSSION

... Ireland and the UK ...

A pronounced short-wave trough is forecast to cross the region along with a frontal boundary. Marginal and skinny CAPE is forecast by the models. The CAPE will first be elevated in the zone of WAA, where strongly curved hodographs are simulated. Surface-based storms are expected in the zone of more straight hodographs with 1km flow around 20 m/s and 0-1 km bulk shear between 10 and 15 m/s. Expect isolated tornado and severe wind gust risk with stronger storms.

... Greece to Italy ...

Severe weather will continue over Greece and parts of Italy. Across central-east Greece, low-level jet reaching 20 - 25 m/s is forecast. At the nose of the jet, moist profiles with substantial MUCAPE are simulated. Continuous redevelopment of storms capable of very heavy rainfall is expected in the region, resulting in perhaps widespread flash flooding. Besides heavy rainfall, large hail is also forecast given large amounts of CAPE above-10 deg C isotherm. Across the eastern flank of the Lvl 2, at least some surface based CAPE will combine with strongly curved hodographs and 0-1 km SRH locally above 200 m2/s2 and low LCLs, yielding tornado threat. Further west, towards Italy, weaker shear will result in a lower risk of severe storms. Furthermore, synoptic-scale descent is forecast, which may contribute to the overall decrease of coverage of storms during the day compared to Greece. Nevertheless, isolated heavy rainfall or large hail event is still expected over S Italy. Furthermore, a tornado or two may occur especially along the coastlines, where the 0-1 km bulk shear can exceed 10 m/s.