Mesoscale Discussion
Valid: Wed 26 Aug 2015 16:00 to Wed 26 Aug 2015 21:00 UTC
Issued: Wed 26 Aug 2015 16:39
Forecaster: GROENEMEIJER
As of 16 UTC ... water vapour satellite imagery indicates that a shortwave trough is crossing the central English Channel providing incraasing upward motion over NW France, the southern North Sea and Benelux. Across these areas, relatively modest instability of 500 J/kg has likely developed, although this is hard to ascertain given the poor coverage of radiosonde data across the Benelux countries.
Ahead of the trough, a number of storms have developed over NW France and the Southern North Sea. Given the highly-sheared environment in which they develop, they will likely include supercells among linearly-organized convection.
Until 21 UTC...the storm activity is forecast to develop further to the northeast across the indicated area. The low-level shear is forecast to strengthen as 1 km AGL winds increase to 20-25 m/s, yielding 10-15 m/s 0-1 km shear. Along with a tendency of surface winds to back ahead of a zone of surface troughdiagnosed near a line from Dunkirk to Paris, a relatively favorable environment for tornadoes should develop.
Summary... a few tornadoes, scattered severe wind events and possibly some large hail are likely across the indicated area until 21 UTC.
Valid: Wed 26 Aug 2015 16:00 to Wed 26 Aug 2015 21:00 UTC
Issued: Wed 26 Aug 2015 16:39
Forecaster: GROENEMEIJER
As of 16 UTC ... water vapour satellite imagery indicates that a shortwave trough is crossing the central English Channel providing incraasing upward motion over NW France, the southern North Sea and Benelux. Across these areas, relatively modest instability of 500 J/kg has likely developed, although this is hard to ascertain given the poor coverage of radiosonde data across the Benelux countries.
Ahead of the trough, a number of storms have developed over NW France and the Southern North Sea. Given the highly-sheared environment in which they develop, they will likely include supercells among linearly-organized convection.
Until 21 UTC...the storm activity is forecast to develop further to the northeast across the indicated area. The low-level shear is forecast to strengthen as 1 km AGL winds increase to 20-25 m/s, yielding 10-15 m/s 0-1 km shear. Along with a tendency of surface winds to back ahead of a zone of surface troughdiagnosed near a line from Dunkirk to Paris, a relatively favorable environment for tornadoes should develop.
Summary... a few tornadoes, scattered severe wind events and possibly some large hail are likely across the indicated area until 21 UTC.