CONVECTIVE FORECAST
VALID 06Z SAT 24/01 - 06Z SUN 25/01 2004
ISSUED: 23/01 19:52Z
FORECASTER: DAHL

There are no thunderstorms forecast.

SYNOPSIS

Upper ridge ATTM over SW Europe will have weakened by Saturday 06Z ... as vort max ATTM over the N Atlantic is digging southeast ... reaching the NW Mediterranean late in the FCST period. Associated DCVA band downstream of the vort max is expected to promote weak cyclogenesis over the NW Mediterranean Sea early Sunday morning. Vort maxima at the periphery of extensive SE European upper low will cross the Ionian and the Aegean Sea during the period ... thereby supporting weak cyclogenesis along frontal boundary which will curve from the central Mediterranean Sea across the Alps and central Germany into N Europe.

DISCUSSION

...Mediterranean...
Shallow cellular convection (EL's possibly AOA 700 hPa) will likely be present over the Adriatic ... the Ionian and the Tyrrhenian Sea. Despite the shallowness of the convection ... an isolated lightning strike or two may be possible. However ... a GEN TSTM area is not necessary for this activity.

It looks that rather intense vort max will overspread frontal boundary over the S-central Mediterranean Sea during the day ... reinforcing weak SFC low along the boundary. Soundings suggest nearly neutral lapse rates in the air mass S of the front for SFC-based parcels and increasing forcing for UVM along the front could promote a few TSTMS. However ... it appears that bulk of this activity will be just S of the forecast area ... and a GEN TSTM area is not warranted ATTM.

Another potential focus for a few lightning strikes will be the NW Mediterranean Sea late Saturday night/early Sunday morning. Soundings of the pre-frontal air mass indicate weak elevated instability (ref. Camborne Friday 12Z ascent). As UVV's overspread this air mass late Saturday night over the NW Mediterranean ... chance for an isolated TSTM or two will likely exist. However ... coverage of TSTMS is expected to remain too sparse for a GEN TSTM outlook ATTM.

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