Storm Forecast
Valid: Mon 14 Mar 2011 06:00 to Tue 15 Mar 2011 06:00 UTC
Issued: Sun 13 Mar 2011 22:16
Forecaster: DAHL

No threat levels issued.

... SYNOPSIS ...

A deep upper longwave trough is anchored off the W-European Atlantic coast, maintaining a deep, southerly flow over western and much of central Europe. While the overall pattern over these regions remains largely unchanged during the period, high pressure over Scandinavia will strengthen and begin pushing cold/polar air southwards.

... DISCUSSION ...

... France ... Iberia ...

Weak instability should persist/develop over Iberia/France, which may lead to scattered/weak thunderstorms as DCVA-related ascent overspreads the region. Shear and instability should both be minimal, suggesting minimal severe threat.

... western Mediterranean Sea ...

Farther east over the western Mediterranean, warm-advection/frontogenesis should lift weakly unstable air, which should result in scattered storms throughout the period, with a slight strengthening trend towards the evening/night hours.

There will likely be no consistent juxtaposition of favorable shear with instability, but at least temporarily some 20 m/s DLS and 10 m/s LLS should coincide with the convection. This combination hints at a potential for line segments and mesocyclones, capable of marginally severe winds/hail, as well as a brief tornado or two. However ... given the large-scale WAA/frontogenesis regime, the storms may tend to be elevated, so that the low-level vorticity cannot be tapped. Also, it seems that the strongest CAPE will remain displaced from the best shear. Overall, the severe threat thus seems to be somewhat patchy and conditional. Will thus not introduce a LVL1, though an isolated severe thunderstorm report or two cannot be discounted.

... south-central Europe into northern Italy ...

It seems that marginal and rather shallow instability may develop with the early March solar heating, leading to scattered showers, some of which may produce sporadic lightning. The severe threat with this activity should be minimal.