Storm Forecast
Valid: Tue 15 Feb 2011 06:00 to Wed 16 Feb 2011 06:00 UTC
Issued: Mon 14 Feb 2011 18:56
Forecaster: KOROSEC

A level 1 was issued for NW Iberia and surrounding areas mainly for intense rainfall and strong wind gusts.

SYNOPSIS

The dominating feature is the eastwards expanding long-wave trough across western half of Europe where surface cyclogenesis develops in the NW Mediterranean. At surface, a deep low moves from eastern Atlantic towards the western France by Wednesday morning. Another short wave trough crosses SE Mediterranean during the forecast period. Over NE Europe, a large ridge with polar airmass maintains high pressure area.

Marginal instability seems likely to form ahead of the approaching front in western Mediterranean. Despite shear will be rather moderate, mostly scattered showers and thunderstorms can be expected. And organized storms are unlikely to form. Though some of the storms may bring intense rain threat, but will stay over open waters.

In weakly sheared but marginally unstable environment, some convective storms are also expected along the rapidly eastwards moving trough across the SE Mediterranean.

DISCUSSION

... NW Iberia and surrounding areas...

Within the polar maritime airmass from the southern UK towards northern Iberian peninsula, scattered showers and weakly electrified storms are expected. Shear will be weak, but given the steep lapse rates, convective activity is expected.

Higher probability of storms seems likely later in the evening/night when the trough with strong surface cold front extending from the main deep surface low approaches from the NW. A plume of WAA will maintain unstable conditions again during the day and with strong ascent along the coming trough, storms will likely form. Given the moderate to strong shear in place, NW Iberia and areas to its NW will be exposed to strong wind gusts and locally intense rainfalls. The threat level 1 was issued for these areas.