Forecast Update
Valid: Mon 04 Nov 2013 06:00 to Tue 05 Nov 2013 06:00 UTC
Issued: Sun 03 Nov 2013 23:33
Forecaster: GROENEMEIJER

A level 1 was issued for parts of the central Mediterranean Sea, mainly for extreme rain.

A level 1 was issued for parts of SW France, mainly for tornadoes.

A level 1 was issued for parts of the Netherlands, mainly for tornadoes and excessive precipitation.

SYNOPSIS

Please refer to the original forecast.

DISCUSSION

...Benelux...

We update the forecast regarding the Benelux as more confidence has arisen is the availability of marginal deep instability south of the surface cyclone over the S North Sea at 06 UTC. It appears likely that clustered deep, moist convection will occur near a cold front with a very pronounced wind-shift. Given the presence very strong low-level shear of 20 m/s and of extreme 0-1 storm-relative helicity values (> 500 m2/s2), some risk of tornado formation will be present. In addition, regional models forecast very large amounts of precipitation in a short time span, which may become hazardous.