CONVECTIVE FORECAST
VALID 06Z THU 21/08 - 06Z FRI 22/08 2003
ISSUED: 20/08 16:47Z
FORECASTER: HUGO

General thunderstorms are forecast across SOUTHERN EUROPE, EASTERN EUROPE & NORTHEASTERN EUROPE

SYNOPSIS

Northwestern parts of Europe, mainly the UK will be dominated by a cyclonic pattern in association with a developing surface and upper level low pressure to the Northwest of the UK in conjunction with a left exit jet streak over the system and associated PV...A large section of central Europe will be dominated by a ridge of the Azores high this making progress Eastwards throughout the forecast period...Southern parts of Europe will experience diurnal mesoscale heat low development during daylight hours, while Scandinavia will be effected a filling surface low pressure and associated occluded front stretching into far Eastern parts of Europe...

DISCUSSION

...GEN RISK REGION (SEE TEXT AREA)...
The whole of the GEN risk region will be at risk of diurnal convective activity especially over Southern portions of Europe in association with diurnal mesoscale heat low development...Southern regions of Europe will see convective activity develop during the early part of the afternoon bringing the risk of scattered thunderstorms to anywhere within the GEN RISK region by mid to late afternoon...Forecast lowest 30hPa MLCAPE values are generally in the region of 800 and 1200j/kg with a region of higher CAPE over parts of Central and Southeastern Spain in which forecast soundings show possible MLCAPE values in excess of 1500j/kg however soundings show a substantial stability layer over Spain within the lowest sections of the atmosphere, as a result CIN values are in excess of -150j/kg and CAP values are greater than 3.5C...If convection can initiate over parts of Spain there is a minimal risk of multicell development but thunderstorm activity is expected to remain below severe limits and this applies to the whole of the GEN RISK region...Scandinavia and parts of far Eastern Europe within the GEN RISK region may see more of a dynamic convective component during the course of the day in association with the occluded front from the surface low pressure over Scandinavia but even this feature will gradually weaken in association with an Eastward moving region of rising surface pressures from the Azores ridge through Central Europe...Any convection within the GEN RISK zone during the course of the afternoon is expected to remain below severe limits however some minimal hail and gusty winds (30-40mph) are possible in association with more of the significant convective activity during the middle afternoon to early evening...Any convection will decay after sunset...

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