Storm Forecast
Valid: Thu 30 Jan 2020 06:00 to Fri 31 Jan 2020 06:00 UTC
Issued: Thu 30 Jan 2020 00:44
Forecaster: GATZEN

A level 2 was issued for the east Mediterranean mainly for severe wind gusts and excessive precipitation and to a lesser extent tornadoes.

A level 1 was issued across Scotland mainly for severe wind gusts and to a lesser extent tornadoes.

SYNOPSIS

An east-European trough will digg towards the east Mediterranean on Thursday. This will be associated with a mid-level front progressing east. In the wake of the trough, dry low-level air masses affect much of eastern Europe. Ridging across western Europe leads to limited lapse rates. An exception are steeper lapse rates within an intense short-wave trough that travels into the North Sea in the afternoon. Substantial CAPE is only forecast over the east Mediterranean, though.

DISCUSSION

East Mediterranean

Within the east European mid-level trough, an intense vorticity lobe travels from the Balkans towards Cyprus. Strong Q-vector convergence follows across Turkey and the north-east Mediterranean. At low levels, cyclogenesis will result in a storm system over the east Mediterranean late in the period. Deep moist convection is forecast ahead and along the cold front that enters the shores of the east Mediterranean on Friday morning as stretching increase the lapse rates within a moist pre-frontal air mass. CAPE of several 100 J/kg will overlap with long, mostly straight-line hodographs and up to 20 m/s 0-3 km bulk shear. Given the strong forcing, linearly organized storms are forecast that move east capable of producing severe wind gusts. Furthermore, excessive precipitation is forecast, in particular across southern Turkey where upslope flow if present, but also other areas are expected to be at risk. Finally, some tornadoes are not ruled out due to local modifications of the low-level wind profile by the topography.

Scotland to North Sea

An intense mid-level jet and tropopause fold cross Scotland into the North Sea on Thursday. Lapse rates will increase due to stretching and steep lapse rates will overlap with rather high moisture across Scotland and parts of the North Sea. Weak CAPE will develop and showers and thunderstorms are forecast that organize along a line capable of producing severe wind gusts since strong vertical wind shear is present (20 m/s 0-1 km bulk shear). Tornadoes are also not ruled out since 0-1 km SRH is high (300+ m²/s²). Later in the day, models indicate weakening moisture and lapse rates near the tropopause fold, and weak CAPE is expected to limit the potential of convective storms in the strongly-sheared environment.