CONVECTIVE FORECAST
VALID Sun 14 Aug 10:00 - Mon 15 Aug 06:00 2005 (UTC)
ISSUED: 14 Aug 10:01 (UTC)
FORECASTER: DAHL

There is a slight risk of severe thunderstorms forecast across northern Italy.

SYNOPSIS

Upper low over the British Isley by Saturday evening is progged to continue to dig south ... reaching NRN Italy towards early Monday morning. Downstream ... several rather weak vort maxima are imbedded in broad WSWLY mid/upper flow over the eatsren half of Europe. SFC low associated with the British upper low ... is expected to fill while tracking into Germany late Sunday afternoon. Unseasonably cold conditions continue across much of central Europe ... with subtropical/moist air persisting across the Mediterranean and SE Europe.

DISCUSSION

...N Italy ... Austria ... NW Balkans...
00Z soundings indicate that 1000+ J/kg afternoon CAPEs should be available across Italy. With diurnal heating ... and increasing DCVA ahead of the approaching upper low ... scattered TSTMS should be possible. TSTM coverage should increase over NRN Italy in closer proximity to the upper low in the late afternoon/early evening hours. Shear should be favorable for severe evolution with 20 to 25 m/s mid-level flow ... supportive of line segments/bow echoes and supercells with severe wind gusts and large hail. Low-level shear profiles do not seem to increase too much ... nonetheless a brief tornado cannot be excluded if local effects act to augment the low-level wind profile.

Weak cyclogenesis is progged to accompany the upper low over N Italy and the NRN Balkans ... with strong frontogenetically-forced ascent across Austria and the NW Balkans. Models produce large amounts of precip with this feature ... though it appears that it will be mainly stratiform in nature. However ... a few convective cells could be imbedded. Severe TSTM threat currently appears to be limited as available CAPE and shear in the cloud-bearing layer should be rather low.

...Bulgaria ... Greece...
Isolated TSTMS may form over the S Balkans ahead of weak vort max. 00Z thermodynamic profiles are featuring varying boundary-layer moisture depth ... and especially over elevated terrain the moisture tends to be mixed out. However ... locally moisture is likely to be deep enough to be supportive of about 1000 J/kg CAPE. Deep shear seems to be strongest over Bulgaria and Greece with about 15 m/s. This may support isolated large hail and strong/severe wind gusts ... but allover severe threat should be insufficient for a SLGT.

...W Germany ... Benelux ... NE France...
Though a few weak convective cells are present along the cold front stretching across central Germany into France ... postfrontal environment should prove to be focus for TSTMS in the afternoon hours. Though deep shear should be rather low ... as should be the CAPE ... a few short-lived funnels/weak tornadoes cannot be ruled out. Severe threat is too low for a SLGT however.

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