Storm Forecast
Valid: Sat 24 Oct 2015 06:00 to Sun 25 Oct 2015 06:00 UTC
Issued: Fri 23 Oct 2015 20:44
Forecaster: DAFIS

A level 1 was issued for S Greece and SW Turkey mainly for excessive rain, large hail, severe wind gusts and tornadoes.

SYNOPSIS

Two high pressure systems dominate in Europe, one is the Azores high and another one over central parts of the continent.
A low pressure system is located in South Greece, where tremendous rainfall amounts have been accumulated since Thursday and numerous tornadoes have been reported. The upper-air cut off low system with its jet streak is slowly moving eastwards and dissipates during Saturday, but strong north flow over the Aegean Sea will advect unstable air masses over land and very high rain accumulations are expected.
Another cyclonic vortex over Iceland sends an extensive cold front towards the British Isles and the Scandinavia where also high rain accumulations are forecast but in non-convective mode, so no level is issued.

DISCUSSION

.... Greece and Turkey ....

According to NWP models about 1000 J/kg of MLCAPE is expected in southern parts of the Aegean Sea, especially north from the island of Crete. Mixing ratio values in the BPL are currently measured up to 12-14 g/kg and ongoing storms in Cyclades produce more than 40 mm of rain in 2 hours (Friday night). As the cyclonic vortex over S Greece moves E - SE-wards, the North flow over the Aegean Sea is forecast to advect the aforementioned unstable air masses over the island of Crete and storms will be able to produce heavy rain mainly driven by the steep toporography. DLS is not expected to exceed the 15 m/s according to GFS and ECMWF. High resolution NWP models, such as BOLAM and WRF produce up to 100mm / 6hr especially for western parts of Crete, where PW is calculated up to 45 mm. For the rest parts of level 1 such as SW Turkey and Dodecanese, scattered storms will be able to produce large hail and severe wind gusts, but also waterspouts / tornadoes as LLS is forecast (10 m/s) and LCL will be below 600m.