Storm Forecast
Valid: Sat 25 Feb 2017 06:00 to Sun 26 Feb 2017 06:00 UTC
Issued: Sat 25 Feb 2017 01:43
Forecaster: TASZAREK
A level 1 was issued for S Italy mainly for the large hail and severe wind gusts.
A level 1 was issued for parts of Croatia, Montenegro, Albania and Greece mainly for excessive precipitation and in lesser extent for tornadoes.
A level 1 was issued for W British Isles mainly for severe wind gusts.
SYNOPSIS and DISCUSSION
Ridge stretches from Azores through Iberian Peninsula up to France. Two long-wave troughs travel through Europe, one moves from CNTRL to E Europe and the second enters British Isles in the end of the forecast period. Southwardly moving cut-off is located over CNTRL Mediterranean. Another ridge covers E Mediterranean and Turkey. A shallow weak convection with a marginal lightning potential may develop within a mid-level wave over Belarus and Ukraine. Although boundary layer will be quite dry (2-3 g/kg MIXR) a very steep lapse rates (> 8 K/km) will provide 100-200 J/kg CAPE. Weak lightning activity is also possible with upcoming cold front affecting W British Isles around noon hours. Strong linear forcing of relatively moist boundary layer (MIXR ~ 6-7 g/kg) produces lobes of CAPE up to 100-200 J/kg and thus shallow-convection which combined with strong low-level flow (~ 25 m/s at 850 hPa) poses a threat of severe wind gusts along frontal boundary.
The best conditions for DMC occurs in CNTRL Mediterranean where ~ 10 g/kg MIXR and ~ 7 K/km lapse rates on the E edge of the trough produces CAPE up to 600-1000 J/kg. Thanks to the support of QG-lift and good overlap with 20-25 m/s DLS, multicell and supercell thunderstorms are possible. Within these, large hail up to 3-4 cm and severe wind gusts may occur, mainly in S Italy in the afternoon hours. Superimposing large-scale precipitation with orographic forced convection creates also a small threat for excessive precipitation in the zone stretching from S Croatia to NW Greece. Due to enhanced LLS and SRH in the evening hours, a marginal tornado potential exists also along SE Adriatic coast.
