Storm Forecast
Valid: Sun 11 Jun 2006 06:00 to Mon 12 Jun 2006 06:00 UTC
Issued: Sat 10 Jun 2006 20:48
Forecaster: DAHL

SYNOPSIS

Omega upper flow pattern is expected to attain slight positive tilt during the period ... with amplification and expansion of associated SFC high-pressure area over central portions of Europe ... which maintains advection of moist and weakly unstable air into western Europe. Strong vort max associated with SE European upper low is progged to into the S Adriatic Sea/S Italy late in the forecast period.

DISCUSSION

W France ... UK

It seems that severe TSTM threat across western Europe will remain rather limited given rather weak shear and little forcing for UVV's ... and a resultant small TSTM coverage ... or even a complete failure of storms to initiate. It seems that a few multicellular storms could form over very NW France ... which may account for wind gusts and hail which may reach severe limits ... but allover severe threat should be rather low.

LL warm advection regime over the Gulf of Biscay and the British Isles may support scattered elevated TSTMS in the late evening and early morning hours.

SE Europe

Rather widespread convection should form in the vicinity of the SE-European upper low again ... which features band of quite intense mid-level winds at its periphery ... which should provide favorable shear for any cell which manages to form in this regime. However ... GFS assumes bulk of convection just outside of favorably sheared regions.

Italy

Another focus for convective development may be strong DCVA regime which should overspread the Adriatic Sea and Italy in the early afternoon hours. These storms should profit from 25 m/s deep shear ... and a small bow echo or mesocyclone cannot be ruled out. Main threats should be marginally severe hail/wind gusts ... though LL thermodynamic fields should also be supportive of a tornado. Allover tornado threat should be rather limited however given fairly weak LL shear. Some uncertainty exists on the evolution of deep instability ahead of the vort max ... and will thus not introduce a level-one threat ATTM. An upgrade may be necessary on Sunday however.