Storm Forecast
Valid: Tue 24 Apr 2018 06:00 to Wed 25 Apr 2018 06:00 UTC
Issued: Mon 23 Apr 2018 22:06
Forecaster: DAFIS

A level 1 was issued for the Balkans mainly for large amounts of small hail and/or large hail, severe wind gusts, and excessive precipitation.

A level 1 was issued for Portugal, S Spain, N Morocco and NW Algeria mainly for large hail and severe wind gusts.

SYNOPSIS

Cold mid-tropospheric air masses create steep lapse rates in a large part of Europe and along with diurnal heating, we expect widespread convective phenomena on Tuesday 24/04. In North Europe, the zonal flow leads to stable conditions with dropping temperatures and windy conditions. Two cold drops are weakening over NW Africa and over S Greece. In addition, two short-wave troughs will affect Italy and the Balkans, where we expect the more active storms. At the surface, no strong frontal zone exists, except from the right edge of the elongated cold front, extending from France towards and the Black Sea.

DISCUSSION

.... Balkans ....

Steep lapse rates and warm/moist low-level air masses will create a very unstable environment. Upper-level wind fields are weak, reducing the DLS values below 10 m/s, so clustering will be very difficult if none. Nevertheless, pulsating storms will be able to produce large hail and severe wind gusts. A level 1 has been issued for the areas more prone to severe weather events. Severe wind gusts are mostly expected in the eastern part of level 1, in Moldova and Ukraine due to the deep boundary layer, fat CAPE profiles, and stronger 850 wind speeds compared to the C-W Balkans. Slow moving storms may cause flash floods or disruptions due to large amounts of small hail.

.... Iberian Peninsula, NW Africa ....

The cold drop that is trapped between the Iberian Peninsula, NW Africa, and the Azores continues to create unstable conditions for almost a week now. Models suggest the development of up to 2 kJ/kg CAPE in S Spain, overlapping with 15-20 m/s. Storms may cluster in a MCS or supercells able to produce large hail and severe wind gusts. Waterspouts cannot be ruled out.