Storm Forecast
Valid: Sun 19 Nov 2006 06:00 to Mon 20 Nov 2006 06:00 UTC
Issued: Sat 18 Nov 2006 18:49
Forecaster: DAHL

SYNOPSIS

Upper long-wave trough will remain anchored over the North Atlantic. A perturbation at its W periphery is expected to lead to intense cyclogenesis, resulting in one large and intense surface-low complex over northern parts of Europe and the eastern Atlantic. Weak perturbations will also continue to affect the Mediterranean regions though the surface-pressure field is progged to remain largely flat.

DISCUSSION

... N Portugal ...

It seems that only potential for severe evolution exists over northern Portugal and extreme NW Spain where marginal deep-layer shear but 12 m/s 0-1 km shear are expected to be in place. Given nearly neutral and saturated profiles, low-level capping should be accordingly weak and threat for an isolated tornado or two exists. However, GFS suggests only a very narrow overlap of CAPE > 0 and the strong LLS region, and a categorical risk will not be issued at this time. However, situation should be monitored for possible shifts of the favorably sheared region towards the south and west, which would increase the area potentially experiencing severe thunderstorms.

Otherwise ... shear and thermodynamic profiles should be too weak to support a significant severe weather threat.