Storm Forecast
Valid: Thu 29 Oct 2009 06:00 to Fri 30 Oct 2009 06:00 UTC
Issued: Wed 28 Oct 2009 21:24
Forecaster: GATZEN

A level X was issued for (area name) mainly for (severe weather type(s)). (repeat for each area)

SYNOPSIS

A long-wave trough over eastern Europe amplifies into the Black Sea region during the period. It is filled with cold and rather dry low-level air masses, and moist convection is quite unlikely over most places. To the south of this trough, rather low geopotential is present over the east Mediterranean Sea. While cool and dry air masses spread into the Aegean region, rather moist low-level air remains south of Turkey. Rich low-level moisture is also situated over the west Mediterranean in the range of a broad ridge associated with stable lapse rates as well as over the Atlantic Ocean, where subtropical maritime air masses advect into the British Isles east of intense low pressure systems.

DISCUSSION

East Mediterranean

South of the Turkish coast, the low-level air is characterized by rich moisture around 11 g/kg mixing ratio due to the warm sea surface. In the range of weak geopotential, some instability is likely. The best potential of deep moist convection is expected to the east of the forecast region in the range of a weak surface low that provides low-level convergent flow, but some showers and thunderstorms may also form further west. Given the weak vertical wind shear, organized thunderstorms are not expected. Waterspouts are not ruled out south of the Turkish coasts, while excessive rain due to slow-moving storms may be a threat further east near Cyprus.

Ireland

In the range of the maritime air mass, weak instability may develop to the east of the main jet streak curving around the Atlantic trough. This instability is expected to be too shallow to produce thunder. Strong showers may develop, though.

Romania, Bulgaria

An intense mid-level trough will spread into Romania and Bulgaria late in the period. While dry low-level air masses spread southward over most places, some moisture may remain over southern Romania and eastern Bulgaria in the range of a weak frontal boundary. Given the strong QG forcing, intense precipitation is likely in the range of this boundary, and moist-adiabatic profiles will likely develop. Limiting factor for deep moist convection is the weak low-level convergence and increasing cold-air advection late in the period. Thunderstorms seem to be not likely.