Storm Forecast
Valid: Tue 21 Apr 2020 06:00 to Wed 22 Apr 2020 06:00 UTC
Issued: Mon 20 Apr 2020 22:26
Forecaster: DAFIS

A level 1 was issued for Spain for excessive precipitation, large amounts of small hail and severe wind gusts.

A level 1 was issued for E Turkey, N Iraq, and NW Iran mainly for large hail and severe convective wind gusts.

SYNOPSIS

A high-pressure system in North Europe results in cold air advection in eastern parts of the continent, while several short-wave troughs slide along the southern parts of the ridge. The coldest drop over the Iberian Peninsula will result in numerous storms on Tue 21/04, but thermodynamic parameters show a limited threat for severe weather events. Another cut-off low is present in Central Mediterranean, associated with a low-level pressure system that created an elongated warm-conveyor belt covering Italy and most of the Balkans where mainly non-convective precipitation is recorded. A rather dangerous set-up is unfolding in the Middle East where a jet is crossing unstable air masses and organized convection is expected.

DISCUSSION

.... Spain ....

The cut-off low destabilizes the air masses over Spain and Portugal but there is no important overlap of CAPE and DLS, except the eastern parts of Spain. A few storms may take advantage of DLS and become organized, increasing the threat of excessive precipitation, but they will mostly stay offshore. High PWAT values (20-30 mm), especially over the Balearic Islands justify the threat of flash floods and possibly large amounts of small hail in the afternoon due to steep lapse rates and freezing levels below 3 km. The remnants of MCSs may survive until the early morning of Wed 22/04, moving east towards Italy but predictability is low given the very different model outputs.


.... Turkey, Iraq, Iran ....

At the eastern edge of our domain, a low/mid-level jet will cross over unstable air masses increasing the DLS up to 25 m/s. An overlap of 1-2 kJ/kg MLCAPE and 15-25 m/s DLS increases the probability of supercells. In addition, directional wind shear will be present and SREH0-3km reaches values up to 500 m2/s2. LCLs will be above 1000 m height, resulting in the evaporation cooling of the downdrafts. Supercells will be able to produce large hail and severe wind gusts.