CONVECTIVE FORECAST
VALID Sat 05 Nov 06:00 - Sun 06 Nov 06:00 2005 (UTC)
ISSUED: 04 Nov 19:57 (UTC)
FORECASTER: DAHL

SYNOPSIS

Upper long-wave trough over WRN Europe is continuing eastwards ... and should close off into a cut-off cyclone over the W Mediterranean late in the period ... with the NRN part of the trough accelerating NEWD into the Baltic States. Upstream Atlantic trough is expected to reach the W British Isles by Sunday 06Z. Extensive SFC low complex should persist over NRN portions of Europe and the NE Atlantic ... with rather quiescent conditions over the Mediterranean.

DISCUSSION

...western Mediterranean...
Weakly unstable air mass should be present over the western Mediterranean ... and DVCA-related UVVs should lead to scattered TSTMS ... mainly along frontal boundary expected to stretch from NW Algeria into N Italy by Saturday 12Z. GFS 12Z and NMM advertise DLS of about 35 m/s ... while MM5 offers more modest 15 to 20 m/s ... though maximum shear seems to be somewhat offset to the W of the CAPE maximum in all solutions. Nonetheless ... shear should be sufficient to support a few severe storms though allover threat should be somewhat limited given poor CAPE and rather weak large-scale UVVs. Expect isolated linear/bowing segments with main threat being severe wind gusts ... though some hail and a brief tornado cannot be excluded ... especially if supercells occur. ATTM a SLGT does not appear to be necessary however.

...British Isles...
It seems that plume of moist/Atlantic air ... containing weak CAPE ... will advect across the British Isles late in the period. Potential for narrow strongly forced convective rainband exists along the SFC front ... with an attendant ... albeit small ... threat for severe wind gusts ... hail and tornadoes. Uncertainty on evolution of thermodynamic fields precludes a SLGT ATTM.

...SRN Sweden...
In the wake of central European frontal system ... models hint at evolution of weak CAPE over S Sweden. Convection should be rather shallow and weak ... and a TSTM area does not appear to be warranted.

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