Storm Forecast
Valid: Sun 27 Jan 2008 06:00 to Mon 28 Jan 2008 06:00 UTC
Issued: Sat 26 Jan 2008 23:22
Forecaster: DAHL

SYNOPSIS

Outbreak of deep polar air is affecting eastern Europe and western Russia, associated with a deep upper long-wave trough. Deep upper ridge is present upstream over central and western Europe ... maintaining stable conditions over these regions.

DISCUSSION

... Norwegian Sea ... central Baltic Sea ...

Comparatievly shallow polar air convection will likely persist over the the Baltic Sea and the Baltic States ... and initially also over the central Norwegian mountains. Per EUCLID, the convection in this post-frontal regime turned out to be more strongly electrified on Saturday than had been anticipated ... and there does not seem to be a reason for a cessation of this activity. GFS simulates the region of deepest CAPE to be located beneath the horizontal 0-6 km shear gradient at the cyclonic flank of the upper jet ... and part of the convection will experience favorable shear profiles. Some of the storms -- especially near the coast -- are likely to be accompanied by quite gusty winds and maybe small hail, but allover severe threat seems to be rather limited.

... central Black Sea ... eastern Aegean Sea ...

As the polar air spreads southwards over the Black Sea and the Aegean Sea, potential for scattered thunderstorms will exist. The southern portions of the Black Sea and the E Aegean will benefit from 20 m/s DLS ... and especially over the E Aegean, steep low-level lapse rates as well as 10 m/s LLS are simulated on Sunday night, suggesting that some potential for (shallow) mesocyclonic storms exists, which could produce a weak/brief tornado ... however, storm tops are currently simulated to be below the 500 hPa level, and given comparatively marginal shear and minimal CAPE, a categorical threat does not seem to be warranted at the moment. However, an upgrade may be necessary if storms turn out to deepen faster than currently anticipated.