Storm Forecast
Valid: Wed 23 Jan 2019 06:00 to Thu 24 Jan 2019 06:00 UTC
Issued: Tue 22 Jan 2019 20:49
Forecaster: PUCIK

A level 1 was issued across N Algeria mainly for heavy rainfall, tornadoes and severe wind gusts.

A level 1 was issued across W Greece mainly for heavy rainfall, tornadoes and marginally large hail.

A level 1 was issued across W and SW Turkey mainly for heavy rainfall and tornadoes.

SYNOPSIS

While much of continental Europe remains under dry and stable conditions, active weather pattern will prevail over much of the Mediterranean during the forecast period. The main macrosynoptic feature will be a deep cyclonic vortex, its center translating from France towards Sardegna during the forecast period. A powerful northerly jet-stream with speeds over 75 m/s at 300 hPa is simulated at the rear flank of the low, driving its southward movement. Apart from the low centre, two troughs are simulated by the NWP. The first trough will cross from the Ionian to the Aegean Se during the forecast period and the second one will affect N Africa during Wednesday afternoon and evening hours.

All of the aforementioned disturbances will be accompanied by isolated to scattered DMC with at least isolated potential for severe convective storm occurrence.

DISCUSSION

... N Algeria ...

A belt of enhanced lower tropospheric moisture will be advected towards the coastline, overlaid by lapse rates at around 6.5 K/km, allowing for marginal CAPE values near the coastlines. Numerous rounds of DMC are possible over the region, enhancing an isolated threat of heavy rainfall.

Besides the rainfall, wind field is forecast to strengthen in the lower troposphere ahead and in the axis of the trough that will cross the area between 15 and 18 UTC. At this time, 850 hPa flow will reach up to 25 m/s, with LLS locally over 15 m/s and SREH reaching 300 m2/s2 over the coastlines. While individual stronger downdrafts may allow for severe wind gusts, low LCLs may, in combination with strong shear in the lowest 1 km allow for a tornado threat.


... W Greece and Turkey coastlines ...

Similarly to Algeria, environmental parameter space will also feature rather low CAPE - strong lower tropospheric shear setup over this region. Thunderstorm activity will be tied particularly to the passage of the mid tropospheric trough and activity will shift from Greece to W Turkey during the forecast period. Combination of LLS up to 15 m/s and low LCLs suggest enhanced tornado threat over both areas. Marginally large hail may occur besides heavy rainfall as well, owing to lapse rates up to 7 K/km, allowing for more buoyancy in the hail growth layer. Hail threat will be most pronounced over S Greece.