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Storm Forecast
Valid: Sun 21 Aug 2011 06:00 to Mon 22 Aug 2011 06:00 UTC
Issued: Sat 20 Aug 2011 20:05
Forecaster: GROENEMEIJER
A level 2 was issued for extreme E Benelux countries and parts of Nrn and central Germany mainly for severe wind gusts and large hail, and perhaps a tornado.
SYNOPSIS
On the eastern flank of a large-scale trough, featuring a cut-off low near its base off the western Iberian coast, very warm air is advected northward. A well-developed mixed layer is covers E Iberia and - as an elevated layer - southern and central France. The air-mass across France is particularly moist with 20-22 C dew points observed across central and southwestern France on Sunday.
DISCUSSION
...Benelux, N France, Germany...
The warm, moist air in France will move northward during the 00-12 time frame, effectively placing a diffuse frontal zone over the Benelux countries. A 30 m/s mid-level jet is collocated with this zone
Elevated convective activity is likely over the southern Benelux/northeastern France. As the air-mass recovers in its wake, 1000-2000 J/kg of MLCAPE should form. This instability combined with about 30 m/s of 0-6 km bulk shear should suffice to sustain rotating storms and bowing systems capable of producing severe wind gusts, given that they initiate.
A small threat of tornadoes will exist as well.
Now an elongated weak PV anomaly is expected to approach the Benelux countries after noon, which will probably induce convective initiation. The coverage of storms is however quite uncertain. I have therefore decided to draw a small level 2 area where coverage ist likely to be highest.
Storm Forecast
Valid: Sun 21 Aug 2011 06:00 to Mon 22 Aug 2011 06:00 UTC
Issued: Sat 20 Aug 2011 20:05
Forecaster: GROENEMEIJER
A level 2 was issued for extreme E Benelux countries and parts of Nrn and central Germany mainly for severe wind gusts and large hail, and perhaps a tornado.
SYNOPSIS
On the eastern flank of a large-scale trough, featuring a cut-off low near its base off the western Iberian coast, very warm air is advected northward. A well-developed mixed layer is covers E Iberia and - as an elevated layer - southern and central France. The air-mass across France is particularly moist with 20-22 C dew points observed across central and southwestern France on Sunday.
DISCUSSION
...Benelux, N France, Germany...
The warm, moist air in France will move northward during the 00-12 time frame, effectively placing a diffuse frontal zone over the Benelux countries. A 30 m/s mid-level jet is collocated with this zone
Elevated convective activity is likely over the southern Benelux/northeastern France. As the air-mass recovers in its wake, 1000-2000 J/kg of MLCAPE should form. This instability combined with about 30 m/s of 0-6 km bulk shear should suffice to sustain rotating storms and bowing systems capable of producing severe wind gusts, given that they initiate.
A small threat of tornadoes will exist as well.
Now an elongated weak PV anomaly is expected to approach the Benelux countries after noon, which will probably induce convective initiation. The coverage of storms is however quite uncertain. I have therefore decided to draw a small level 2 area where coverage ist likely to be highest.
Bericht laatst bijgewerkt: 20-08-2011 22:16
