GaMe®
Legacy Member
Zorba zei:
Valid: Fri 29 Apr 2011 06:00 to Sat 30 Apr 2011 06:00 UTC
Uitleg (gevorderd)
... E-UK, Benelux, parts of France and W-Germany...
Gradient flow increases during the daytime hours as high pressure to the north strengthens. Modest BL moisture content beneath T<-20°C at 500 hPa results in modest mid-level lapse rates and SB/MLCAPE of ~800/500 J/kg. Numerous, weak vorticity maxima, embedded in this strenghtening easterly flow affect the highlighted area during a prolonged period, resulting in scattered thunderstorm activity over a broad area. Main uncertainty... if wind field ramps up fast enough, before instability diminishes due to BL stabilisation. Also, weak low-tropospheric WAA is anticipated during the forecast, which could limit thunderstorm coverage mainly over the Netherlands and NW-Germany. We went with a level 1, where low-end to modest CAPE overlap with up to 12 m/s speed shear and roughly 200 m^2/s^2 SRH-1. LCLs not too low with 1 km, but still an isolated tornado and strong to severe wind gust event is well possible, probably maximized over Belgium. A somewhat enhanced large hail risk exists not only in the aforementioned areas, but also further south over N-central France with low WBZ levels and DLS of 10 - 15 m/s. Hence, the level area was expanded well to the south.
