Storm forecast for Saturday and Sunday
Valid: Sat 04 Apr 2020 06:00 to Sun 05 Apr 2020 06:00 UTC
Issued: Fri 03 Apr 2020 20:35
- A level 1 has been issued across the Aegean Sea region mainly for excessive precipitation and large hail, tornadoes and severe wind gusts.
A European polar trough is filled with cold and dry air masses that expand into most of the Mediterranean. A trough across the west Mediterranean moves east and starts to cut off as mid-level ridging increases across Central Europe. Ahead of the progressing Mediterranean trough, a strong south-westerly flow affects the Aegean and Turkey that turns south-east when the trough center passes late in the period.
An elevated mixed layer advects northward ahead of a cold front. At low levels, moisture is limited and given rather low temperature in the boundary layer, large CIN is present. However, along a mid-level front that moves eastward late in the period, weakening CIN is expected to extent into the moist air mass close to the cold front, and some weakly-capped CAPE can develop.
However, most CAPE will still be elevated as indicated by all available models. Therefore, chances of severe wind gusts and tornadoes are reduced.
Strong vertical wind shear is present along the cold front and overlaps with CAPE especially across the Aegean Sea. Curved hodographs indicate a good potential for rotating storms if sufficient boundary-layer rooting takes place.
Therefore, a few well-organized storms are not ruled out, capable of producing large hail. Severe wind gusts and tornadoes are not ruled out. Given the limitations discussed above, the overall potential is quite low, though.
Most significant severe weather threat will be excessive precipitation, though. To the north of the trough center, south-easterly flow advects moist air masses into the Aegean region. Latest models suggest neutral lapse rates, and non-convective precipitation is forecast, although some embedded storms may develop.
Main threat is along the western Aegean coasts due to upslope flow. Due to the mostly non-convective nature of precipitation, a level 1 has been issued.