Storm Forecast
Valid: Sun 13 Nov 2016 06:00 to Mon 14 Nov 2016 06:00 UTC
Issued: Sat 12 Nov 2016 20:41
Forecaster: KAHRAMAN

SYNOPSIS

Cold air over NE Europe remains, while a sharp ridge with warm tongue approaches to the continent from NW. The high pressure system over much of the continent, and deep Icelandic Low further north, create strong gradients of pressure and temperature in N Europe. In terms of convection, focus of interest during the forecast period will be on two patterns in the south: First is a deep low pressure system, with a sharp trough aloft, moving over SE Europe. A low-CAPE high-SHEAR environment, with strong forcing exist here. This system is already triggering thunderstorms along its cold front, and will be active in W Black Sea and S Aegean Sea for the first few hours. Second pattern is a secondary, westwards trough from the same upper low. It will rapidly amplify towards E Spain during the forecast period, advecting cooler air southwards, and giving birth to a shallow cyclone over the W Mediterranean Sea further in the night.

DISCUSSION

Along the fast cold front in the SE of the forecast domain, latent instability is diminishing in the early forecast period, especially over land. Therefore, thunderstorms can form over W Black Sea and S Aegean Sea, as well as coasts, while the probability is lower over inlands of Turkey. Even some models simulate less than 100 J/kg MLCAPE over the area. 0-6 km shear values of 25-35 m/s favour organized storms, given they form. Although the organization should be linear, some cells may have rotating updrafts. A low level jet favours strong convective gusts with the Black Sea storms, but the confidence is low for exceeding 50 kts.

In the W Mediterranean, up to 500 J/kg MLCAPE overlaps 10-15 m/s deep layer shear in the night. Slow-moving storms may produce locally excessive precipitation, but it is not likely that the amounts will reach severity thresholds. Waterspouts are also not ruled out around the islands here.