Extended Forecast
Valid: Sun 24 Feb 2008 06:00 to Mon 25 Feb 2008 06:00 UTC
Issued: Fri 22 Feb 2008 23:21
Forecaster: SCHLENCZEK

SYNOPSIS

An intense surface low over the Norwegian Sea is forecast to travel northeastwards while weakening. Associated cold front will cross central UK and Scandinavia during the afternoon. High pressure will prevail over large portions of central and southern Europe.

Ahead of a weak upper low, unstable airmass over southwestern Iberia will spread into western Mediterranean. Given 15 to 20 m/s 0-6 km deep layer shear, some multi-cellular storms with possible hail and gusty winds could evolve.


DISCUSSION

North Sea and parts of Norway

In the wake of the cold front, upper level cold air and rather warm SSTs should create some low-end instability. GFS 12Z predicts meager CAPE and intense low level shear in order of 20 m/s near southern Norway. Isolated severe gusts due to downward momentum transport may occur in an environment with more than 25 m/s at 850hPa. Uncertainties about the instability and the final position of the low level jet are too high to issue a level-one threat at the moment. Cold air convection may produce scattered lightning over a broad area and a thunderstorm area seems not warranted.