CONVECTIVE FORECAST
VALID Fri 02 Sep 06:00 - Sat 03 Sep 06:00 2005 (UTC)
ISSUED: 01 Sep 22:25 (UTC)
FORECASTER: DAHL

SYNOPSIS

High-amplitude upper flow pattern is present across Europe ... with slowly eastward moving ... narrowing upper long-wave ridge covering central and northern portions of Europe ... and two adjacent longwave troughs to the east and west respectively. Vort maxima traveling NWWD along the W periphery of the upper ridge are progged to affect the NW portions of central Europe and S Scandinavia during the period. At low levels ... two high pressure areas are progged be centered over the North Sea and over the Baltics respectively ... with narrow tongue of weakly unstable subtropical air present between these features ... stretching from central Europe NWD into NRN Scandinavia. Attached to this plume ... warm/moist ... and weakly capped air mass will cover SWRN parts of Europe ... the Mediterranean ... and SERN Europe.

DISCUSSION

...W Balkans...
TSTMS should form with diurnal heating in nearly uncapped ... and weakly unstable environment from Slovakia into the western Balkan States ... aided by vort max at E periphery of the central European upper ridge. About 15 m/s deep-layer shear should be in place ... which may support an isolated wind/hail even approaching severe levels ... but allover kinematic/thermodynamic setup seems to be too weak for organized severe threat.

...Aegean ...
Low-level shear should increase over the Aegean Region late in the day. Though instabilty will likely be fairly weak ... enhanced shear could promote isolated rotating updraft ... potentially capable of producing a weak tornado. Threat is too low for a SLGT however.

...central Europe ... France ... E Spain ...
Scattered afternoon TSTMS should also form across central Europe ... France and E Spain ... shear profiles are expected to remain fairly weak ... and with CAPEs on the order of a few hundred to may be a thousand J/kg ... severe threat should be rather low.

...Italy...
Wednesday's 12Z ascents across Italy reveal that locally rich BL moisture is in place ... promoting CAPEs in excess of 2000 J/kg. Though shear will be minimal ... storms that form in ... or encounter ... such a thermodynamic environment may be capable of producing marginally severe hail/wind for short periods of time. However ... given that rather weak thermodynamic fields will likely be predominant ... and anticipated lesser extent of convective development per latest model runs ... a SLGT does not appear to be necessary ATTM.

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