Storm Forecast
Valid: Sat 26 Jul 2008 06:00 to Sun 27 Jul 2008 06:00 UTC
Issued: Fri 25 Jul 2008 22:27
Forecaster: DAHL

SYNOPSIS

Rather stationary high-amplitude upper flow pattern persists over Europe during the period ... with a deep long-wave trough over the E Atlantic and an upper ridge over southern Scandinavia ... the only noteworthy changes being that a weakening and slowly northeastward progressing upper low over France and a rather intense upper low over the Ukraine which is expected to move slowly eastward, reaching the W Black Sea late in the period. At low levels, a rather strong northeasterly flow is simulated over E Europe at the southern periphery of the deep-layer Scandinavian high. This flow regime will advect quite most low-level air into central Europe.

DISCUSSION

... Ukraine ... NW Romania ... E Hungary ... E Slovakia ...

It seems that some severe potential will persist across E Europe amidst region of enhanced low-level shear. Deep shear should be somewhat marginal with 10 to maybe 15 m/s, but ample CAPE should be present, suggesting that at least moderately-well organized storms will form. Current thinking is that storms will coagulate into several MCSs, some of which may contain mesocyclones. These will pose a threat for large hail, damaging wind gusts and isolated tornadoes.

... west-central Europe ...

Rather strong CAPE ... which may well reach 2000 J/kg ... should be present over parts of Germany, the Czech Republic, and Austria where LL moisture should be richest. Large-scale forging for upward motion should be quite weak, but little capping should allow mesoscale features like orographically-generated circulations or other boundary-layer systems to initiate the storms. At the moment, it seems that kinematic parameters will be too weak for a categorical risk, though isolated large hail ... quite sporadically attaining severe levels, as well as strong outflow winds may occur. Interaction of cells with outflow boundaries or other mesoscale systems providing enhanced LLS, may support local mesocyclogenesis, augmenting the threat for large hail. Given weak background kinematic fields, a level-one threat does not seem to be warranted, however.