Storm Forecast
Valid: Thu 29 Apr 2010 06:00 to Fri 30 Apr 2010 06:00 UTC
Issued: Wed 28 Apr 2010 22:10
Forecaster: GATZEN
A level 1 was issued for southern France and northern Spain mainly for large hail.
A level 1 was issued for central and northern France as well as the Benelux countries mainly for large hail.
A level 1 was issued for southern Italy mainly for large hail.
SYNOPSIS
A broad ridge over Central Europe weakens and is shifted southward as a pronounced long-wave trough over the north-eastern Atlantic expands into northern Europe. A sharp short-wave trough over the Bay of Biscay shrinks during the forecast period as it is absorbed by the approaching jet. Its slightly negatively tilted axis is expected over Germany at the end of the period. From the low geopotential over eastern Europe, the southern portions cut-off over the Balkans as the axis of the European ridge tilts southward. While a tongue of warm air spreads north-eastward across France and Germany ahead of the short-wave trough, rather cool air masses will be present over eastern Europe and most of the Mediterranean. Cold air will also advect into the British Isles during the period.
DISCUSSION
France and Benelux
Warm and rather moist air advects into France ahead of the approaching short-wave trough. Models indicate low-level mixing ratios up to 10 g/kg. The general set-up seems to be quite unfavourable for severe convection given that the low-level air spreads eastward quickly, leaving the short-wave trough to the west. Weak low-level convergence is expected over most regions, and initiation of storms is rather questionable. Every storm that manages to form will have a good potential to organize given 20 to 25 m/s deep layer vertical wind shear. Current thinking is that isolated storms are possible posing a threat of isolated large hail and severe wind gusts.
The storms are expected to weaken slowly in the evening and night hours, given decreasing instability but on the other hand adequate lifting ahead of the short-wave trough and along the low-level convergence line.
Valid: Thu 29 Apr 2010 06:00 to Fri 30 Apr 2010 06:00 UTC
Issued: Wed 28 Apr 2010 22:10
Forecaster: GATZEN
A level 1 was issued for southern France and northern Spain mainly for large hail.
A level 1 was issued for central and northern France as well as the Benelux countries mainly for large hail.
A level 1 was issued for southern Italy mainly for large hail.
SYNOPSIS
A broad ridge over Central Europe weakens and is shifted southward as a pronounced long-wave trough over the north-eastern Atlantic expands into northern Europe. A sharp short-wave trough over the Bay of Biscay shrinks during the forecast period as it is absorbed by the approaching jet. Its slightly negatively tilted axis is expected over Germany at the end of the period. From the low geopotential over eastern Europe, the southern portions cut-off over the Balkans as the axis of the European ridge tilts southward. While a tongue of warm air spreads north-eastward across France and Germany ahead of the short-wave trough, rather cool air masses will be present over eastern Europe and most of the Mediterranean. Cold air will also advect into the British Isles during the period.
DISCUSSION
France and Benelux
Warm and rather moist air advects into France ahead of the approaching short-wave trough. Models indicate low-level mixing ratios up to 10 g/kg. The general set-up seems to be quite unfavourable for severe convection given that the low-level air spreads eastward quickly, leaving the short-wave trough to the west. Weak low-level convergence is expected over most regions, and initiation of storms is rather questionable. Every storm that manages to form will have a good potential to organize given 20 to 25 m/s deep layer vertical wind shear. Current thinking is that isolated storms are possible posing a threat of isolated large hail and severe wind gusts.
The storms are expected to weaken slowly in the evening and night hours, given decreasing instability but on the other hand adequate lifting ahead of the short-wave trough and along the low-level convergence line.
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