Storm Forecast
Valid: Wed 25 Mar 2015 06:00 to Thu 26 Mar 2015 06:00 UTC
Issued: Tue 24 Mar 2015 22:37
Forecaster: PUCIK

A level 1 was issued for S Iberia, N Morocco, NW Algeria mainly for severe wind gusts.

A level 1 was issued for E Algeria and Tunisia mainly for severe wind gusts and large hail.

A level 1 was issued for S Italy, the Ionian, Adriatic Sea, W Balkans mainly for excessive precipitation, tornadoes, severe wind gusts and to the lesser extent for marginally large hail.

A level 2 was issed for SW Croatia, W Bosnia-Herzegovina and W Montenegro mainly for excessive precipitation, tornadoes and severe wind gusts and to the lesser extent for marginally large hail.

SYNOPSIS

An active weather pattern coninues especially over the western and central Mediterranean with a deep trough over the region. Several short-wave troughs are simulated on the periphery of the larger scale trough. The first one will translate from S France through Iberia towards Algeria, the second one will eject from Italy towards the Balkans. Especially in conjunction with the second short-wave, cyclogenesis and WAA regime is forecast over parts of Italy and Balkans. A major stratiform rain shield will progress N, NE-wards towards the continent with unstable airmass with scattered DMC trailing behind.

DISCUSSION

... S Iberia towards N Morocco and NW Algeria ...

A pronounced short-wave will cross the region between 18 and 00 UTC with a jet-streak embedded in the trough. Cold core of the trough will result in some marginal CAPE over the sea, which in conjunction with the favourable synoptic-scale setting may easily yield isolated to scattered DMC by the evening hours. In strong vertical wind shear and with 850 hPa winds of 15 to 20 m/s, well organised DMC capable of severe wind gusts will be possible.

... E Algeria, Tunisia ...

A day number 2 with possibly severe DMC is forecast over the region. Models forecast the development of another surface low inland and onshore easterly flow should resume by afternoon. Despite the presence of steep lapse rates, modest dewpoints will preclude very high CAPE values. Furthermore, considerable CIN may be present, especially towards the south of the area, making the initiation more questionable. Nevertheless, hundreds J/kg of CAPE should build-up along with 15 to 25 m/s of DLS. Thus, if storms form, they may become supercells with attendant threats of large hail and severe wind gusts.

... S Italy towards Balkans ...

Severe weather threat will quickly shift with the translating short-wave trough. While over S Italy, the highest threat will exist in the morning hours, W Balkans will see the highest threat in the noon to the afternoon hours. As a plume of steeper lapse rates trails the warm front, several hundreds J/kg of CAPE will develop in the warm sector. Strong low-level flow in WAA regime along with the CVA should aid in the initiation along and just behind the warm front. High values of DLS (over 20 m/s) and also of LLS (over 10 m/s) suggest that supercells with severe wind gusts and tornadoes will be possible. Towards the Balkans, the threat of excessive precipitation will ramp up, as 20 to 25 m/s of 850 hPa flow will impinge on the coastline. In such configuration, training pattern of cells will be possible and Lvl 2 is issued for the area with the highest risk of heavy rainfall. Due to the steep lapse rates, marginally severe hail will be possible with supercells, but this threat should be marginal compared to the others.