Foehn - Weather Events

by ZAMG

This CM represents a meso-scale modification of the CM "Cold Front" or "Occlusion" during its passage over a mountain range. The most striking facts are the completely opposite weather events on the windward and on the lee side.

Parameter Description
Precipitation Windward side:
  • Intensive precipitation associated with the Barrage Cloud
Lee side:
  • Dry weather
Temperature Windward side:
  • Cooling by precipitation
Lee side:
  • Very warm and dry wind
Wind Windward side:
  • Directions perpendicular to mountain range
Lee side:
  • Foehn: very warm and dry wind
  • Directions perpendicular to mountain range
Cloud Windward side:
  • Thick Barrage Cloud
Lee side:
  • Cloud free in valleys and immediately to the lee of mountain chain
  • High Cirrus cloud further away
Other relevant information  

27 January 2008/00.00 UTC - Meteosat 9 IR10.8 image; weather events (green: rain and showers, blue: drizzle, cyan: snow, red: thunderstorm, yellow: fog, black: no precipitation)
Menu Of Foehn
Typical Appearance In Vertical Cross Sections
References