Storm Forecast
Valid: Fri 07 Apr 2017 06:00 to Sat 08 Apr 2017 06:00 UTC
Issued: Thu 06 Apr 2017 07:32
Forecaster: TUSCHY

A level 1 was issued for N-Tunisia and NE-Algeria mainly for isolated large hail and excessive rain.

SYNOPSIS and DISCUSSION

An extensive high pressure area covers W-Europe. Further downstream, a longwave trough is analyzed from Finland to W-Turkey with another pool of low geopotential heights extending further W over N-Tunisia and N-Algeria. Embedded in this trough is a compact cold-core low over Romania/Bulgaria, which drifts east.

This configuration supports widespread advection of a cool and dry air mass from Scandinavia far to the south. Regionally enhanced BL moisture or steeper mid-level lapse rates cause a few areas with weak/modest CAPE and isolated to scattered thunderstorms are forecast. Graupel and gusty winds will be the main hazard.

A few large hail events are possible over N-Tunisia/NE-Algeria, where broader mid-level CAPE profiles in forecast soundings support more intense updrafts (in addition to 15 m/s DLS). Clustering storms may also cause localized flash flood problems in that area, so a level 1 was added.

Parts of the Ukraine/far SW Russia may also see better MLCAPE in excess of 500 J/kg, but DLS of 10 m/s should lower the overall hail risk. Hence no level 1 was issued despite the chance for an isolated large hail event in strongest thunderstorms.