Storm Forecast
Valid: Wed 03 Apr 2019 06:00 to Thu 04 Apr 2019 06:00 UTC
Issued: Wed 03 Apr 2019 06:26
Forecaster: PUCIK

A level 1 was issued across northwestern Mediterranean and Ligurian Sea mainly for large hail and excessive rainfall.

A level 1 was issued across northern Africa mainly for large hail and severe wind gusts.

A level 1 was issued across parts of Syria and Iraq mainly for excessive precipitation and large hail.

SYNOPSIS

A deep cyclonic vortex will reside over the British Isles, its base stretching over France and rotating towards the Liguria. The vortex is surrounded by strong flow at the mid to upper troposphere. Isolated to scattered DMC is forecast underneath the cold mid-tropospheric airmass and steep lapse rates, reaching 7.5 K/km, underneath.

A cold front will progress across the northwestern Mediterranean and Ligurian Sea eastward, while it will remain quasistationary and in the wavy form as low pressure develops over southern Germany. Scattered thunderstorms will form ahead and along the cold front particularly in the evening hours in the tongue of enhanced moisture.

Diurnally driven DMC is forecast across Turkey and parts of the Middle East, underneath a pool of shallow low geopotentials, in the weak PVA regime.

DISCUSSION

... Northwestern Mediterranean towards the Ligurian Sea...

PVA ahead of the advancing short-wave trough, along with the surface cold front will result in widespread initiation of convection, likely forming a QLCS towards the evening and overnight hours. Southern part of the system will experience a strong, unidirectional, shear with DLS values around 20 m/s and CAPE values between 500 and 1000 J/kg. While the strong linear forcing will remain unfavourable for isolated mode of convection, isolated large hail threat will be present. Towards the north, forecast soundings reveal high RH throughout the troposphere and strong perpendicular component of flow towards the coastline, yielding an enhanced threat of excessive rainfall.

... Western to Central Germany ...

While isolated DMC may already form during the day hours, NWP agrees on the more widespread initiation during the late evening and overnight hours as cold front surges eastward. The environment will feature DLS between 20 and 25 m/s, including SRH up to 300 m2/s2, but forecast soundings reveal that most of the DMC will likely stay elevated above the strongly sheared lower troposphere. Combined with skinny CAPE profiles, the severe weather threat seems too low to warrant a Lvl 1 atm, but the area should be monitored for potential initiation ahead of the cold front, in the environment, where isolated large hail and/or severe wind gusts could occur.

... Northern Africa ...

Long, linear hodographs suggest splitting supercells may occur over this area in the environment of hundreds of J/kg of CAPE. Isolated to scattered initiation is forecast, likely tied to the local topographic features. Stronger, rotating cells will be capable of isolated large hail and severe wind gusts.