Storm Forecast
Valid: Thu 12 Oct 2006 06:00 to Fri 13 Oct 2006 06:00 UTC
Issued: Thu 12 Oct 2006 06:25
Forecaster: GATZEN

SYNOPSIS

Another subtropic ridge spreads into western Europe, while trough axis of Atlantic long-wave trough propagates northward reaching Iceland at the end of the period. Surface cold front slows down over Germany and is expected to disappear on Friday. Over western Mediterranean ... southern vort-max of mentioned trough axis has cut off and should remain near Balearic Islands. Low geopotential over eastern Mediterranean gradually weakens during the period.

DISCUSSION

Western Mediterranean

In the range of the cut-off low ... instability has rapidely increased during the last night due to moisture advection in low levels and mid-level steepening lapse rates. A strong jet streak curving around the southern periphery of the cut-off leading to QG forcing has reached southern Balearic Islands this morning. To the north ... a well-organized MCS has formed during the last hours. Today ... unstable air mass is forecast to remain east of the cut-off low ... while upper jet streak should also spread eastwards ... and it is expected that another round of intense convection will affect western Mediterranean Sea today. Best potential seems to exist SE of Balearic Islands ... where strong DLS and high instability will be present. Thunderstorms that form will likely merge into MCS ... capable of producing strong to severe wind gusts and intense precip. To the north ... warm and unstable air mass advects into north-western Mediterranean east of the cut of. Latest model output suggests WAA and QG forcing ... and embedded thunderstorms are forecast. Moderate to strong north-easterly low-level winds are expected in the WAA regime ... and it is not ruled out that locally strong LLS /SRH will evolve ... and thunderstorms that root to the boundary-layer may become mesocyclones. Given the possiblity of strong LLS ... tornadoes are not ruled out. Chance seems to be quite low, though ... as models do not indicate strong vertical wind shear ATTM.

Germany

Weak instability is indicated by latest soundings due to steep mid-level lapse rates ... but boundary-layer is cool and rather dry. Today ... weak cold front/convergence spreads into the region ... and models indicate that quite moist low-level air mass ... with surface dewpoints up to 16°C ... is advected. This should lead to weaker CIN ... and a few thunderstorms are not ruled out. Weak wind shear is present and severe thunderstorms are not likely. Intense rain will be possible with slow-moving storms.