CONVECTIVE FORECAST
VALID 06Z SUN 27/02 - 06Z MON 28/02 2005
ISSUED: 26/02 19:57Z
FORECASTER: DAHL

There is a slight risk of severe thunderstorms forecast across the Black Sea ... S Ukraine ... NW Turkey.

General thunderstorms are forecast across much of the Mediterranean Sea and SE Europe.

SYNOPSIS

High-amplitude upper flow pattern persisting across the Atlantic and Europe ... with large-scale upper high present over the NRN Atlantic ... and a digging trough to its east ... expected over Scantinavia and N-central Europe by Sunday 00Z. This trough will merge with SLY upper frontal zone ... stretching from Iberia across the Mediterranean and the Black Sea into Russia. Imbedded vort max over the central Mediterranean on Saturday afternoon ... is progged to intensify and reach the central Black Sea/eastern Ukraine by Monday early morning. Most of Europe has been flooded with deep unseasonably cold polar/arctic air masses. Associated cold front should extend from the S Mediterranean across the central Balkan States into central Russia at the beginning of the forecast period ... with fairly intense cyclogenesis expected along this front over Bulgaria early in the day ... resulting in extensive SFC low over the N Ukraine by Monday 06Z.

DISCUSSION

...SLGT area...
Focus for potentially severe evolution will likely exist along and ahead of the cold front of developing cyclone over SE Europe. Air mass ahead of the front should be weakly capped and weakly unstable ... and TSTMS should develop as vort max spreads across the region.

Shear profiles should be sufficient for a few severe TSTMS ... with 500 hPa flow increasing to 35+ m/s late in the day over the Black Sea/Ukraine ... and 850 hPa flow of up to 30 m/s. Nature of low-level forcing is somewhat uncertain ... but kinematic setup suggests that supercells may occur ... maybe amidst linear MCS. Severe wind gusts should be the main threat ... though a tornado or two ... as well as a few large-hail events cannot be excluded.

...central and NW Mediterranean Sea...
Rather shallow SFC-based convectively mixed layer will likely form over the NW Mediterranean in the polar air mass ... Though shallow nature of convection may limit TSTM coverage ... recent cases indicated that quite widespread lightning activity may occur over the Mediterranean even with quite shallow convection ... thus included much if the NW Mediterranean in the TSTM forecast.

#