Storm Forecast
Valid: Mon 12 Nov 2007 06:00 to Tue 13 Nov 2007 06:00 UTC
Issued: Sun 11 Nov 2007 22:34
Forecaster: DAHL

SYNOPSIS

Not too much of a change in the large-scale upper pattern expected on Monday ... with an intense long-wave trough centered over E-central/E Europe. Accordingly, most of Europe will be affected by deep polar air masses, with warm/moist air remaining only over the southern, and especially southeastern parts of Europe. Low-level pressure field features a large-scale cyclonic circulation collocated with the upper feature and weak mesoscale SFC low centers over the Aegean- and Black-Sea regions within the narrowing plume of warm air.

DISCUSSION

... Black Sea ... E Aegean region ...

Main focus for convective activity will exist over an area extending from the Ionian Sea across the Aegean into the Black Sea. It seems that favorable shear will be present only over the Black Sea, which is where some severe threat should exist. Exact shape of the thermodynamic profiles is somewhat uncertain, but model data and soundings from Sunday suggest that steep mid-level lapse rates will persist, and it may be that profiles similar to Sunday's 12Z launch from Istanbul will be met over the Black-Sea region on Monday. The shear profiles should be conducive to multicellular storms and isolated mesocyclones, with the lack of low-level capping suggesting some threat for tornadoes (in addition to low-level shear on the order of 7 m/s). Will include the eastern Aegean and coastal regions of Turkey, the DLS will be somewhat weaker, but LLS should be enhanced by friction, suggesting an increased likelihood for tornadoes.

... N Germany ... N Netherlands ...

Showers and isolated thunderstorms should accompany the polar-air convection moving into N Germany from the North Sea. Since rather strong low-level shear is expected to persist, a brief funnel cloud/tornado cannot be ruled out again, though the threat should be too insignificant to warrant a categorical outlook. Also, lightning will likely be quite sporadic, so that the thunderstorm forecast is only marginally justified.