Storm Forecast
Valid: Sat 24 Dec 2016 06:00 to Sun 25 Dec 2016 06:00 UTC
Issued: Sat 24 Dec 2016 01:54
Forecaster: TASZAREK

A level 1 was issued for Scotland and Shetland for severe wind gusts.

A level 1 was issued for SW Norway mainly for excessive precipitation and severe wind gusts.

SYNOPSIS and DISCUSSION

A long-wave and a deep low with pressure lowering to 960 hPa travels in the forecast period from Iceland to Norwegian Sea. A strong horizontal pressure gradient creates a risk of non-convective wind gusts exceeding 30 m/s in Scotland, North Sea and SW Norwegian coast (850 hPa airflow ~ 30 m/s). Although air in low-levels remains dry (MIXR ~ 3-4 g/kg) , an impressive mid-level lapse rates (~ 7.5 K/km) develop CAPE up to 200-400 J/kg over Scotland, S Sweden, S Baltic Sea and waters between Scotland, W Norway and Denmark. An advection of high PVU provides a good lifting factor. Thanks to these ingredients, an isolated low-topped convection with a small potential of lightning is possible within this area. Locally in SW Norway, a superimposing convective and stratiform precipitation along with persistent orographic lift creates a risk of excessive precipitation.

Minor thunderstorm activity with weak CAPE and weakly sheared environment is also possible within a broad cut-off in E Mediterranean area. A risk of severe convective phenomena is limited.