Valid: Thu 24 Jan 2019 06:00 to Fri 25 Jan 2019 06:00 UTC
Issued: Thu 24 Jan 2019 06:54
A level 1 was issued for southern Turkey, Cyprus, and the east Mediterranean mainly for excessive rain and severe wind gusts and to a lesser extent large hail and tornadoes.
A level 1 was issued for Greece, the Aegean, and the Ionian Sea mainly for excessive precipitation, severe wind gusts, and to a lesser extent tornadoes.
A highly amplified trough is situated across the west Mediterranean and will dig into northern Africa. A strong jet streak curves around its base and ejects into the central and east Mediterranean, affecting Greece and the Aegean late in the period. Downstream, a lifting short-wave trough crosses the east Mediterranean and Turkey in the morning and noon. At lower levels, warm subtropical air is replaced by a cold front. In its wake, a moist maritime air mass will become unstable due to stretching close to a developing mid-level front at the south-eastern flank of the approaching jet streak. Low-level CAPE in the order of 500 J/kg can build that will overlap with long hodographs late in the period.
Northern and Central Europe is dominated by dry and cold air masses. Best potential for some CAPE is across the North Sea where steeper lapse rates are expected, however, thunderstorms are also unlikely here due to marginal CAPE and dry low levels.
A cold front and associated mid-level trough axis will move across the region. Mid-level lapse rates will become quite steep and CAPE will build in the next hours. Along and ahead of the cold front, thunderstorms are forecast that will spread eastward. Long hodographs will support multicells capable of producing large hail and severe wind gusts. Although low-levels are not too moist and low-level CAPE is limited, surface-based storms may also produce a tornado or two give slightly curved, long low-level hodographs. Additionally, there is a threat of excessive rain in particular over southern Turkey with upslope flow ahead of the cold front and some training possible. In the wake of the cold front, storms are expected to decay due to decreasing lapse rates and CAPE.
Central Mediterranean into Greece and the Aegean
An intense low has formed across the west Mediterranean, and severe non-convective winds will continue to affect large parts of the Mediterranean. Thunderstorms are most likely ahead of the low in a moist south-westerly flow from the south Mediterranean towards the Aegean. Latest models suggest improving lapse rates below an approaching mid-level front from the south-west. Low-level CAPE is expected to form ahead of a surface cold front that crosses southern Italy during noon. Band of thunderstorms are forecast to form along and ahead of the cold front and will spread eastward in the afternoon and evening, affecting the Aegean until the end of the period. Main threat is excessive rain from training storms moving along the frontal boundary. However, with improving vertical wind shear, long hodographs are forecast late in the period, supporting more organized storms capable of severe wind gusts and perhaps tornadoes. Tornadoes are more likely close to the coasts of Greece where low-level forecast hodographs are slightly curved. Given the strong low-level vertical wind shear, a strong tornado is not ruled out, although low-level buoyancy is limited.