Barrage cloudiness is an orographically influenced conceptual model. If there is a stream field orthogonal to a mountain range it is blocked by the barrier, forced to rise over or forced to flow around the barrier according to the extent and height of the mountain ridge. This forced rising of the stream leads to adiabatic cooling and, if there is sufficient humidity, to condensation. Consequently, cloudiness with a high probability for precipitation forms at the windward side of the mountain range. The intensity of the precipitation can be very strong and depends upon the distribution of the wind field with height or the type of Barrage. Different types of Barrage events can be distinguished from the direction of the flow and whether there are separate Barrage Clouds or Barrage within frontal zones. Although the latter is usually accompanied by heavy precipitation, in general, a dominating orthogonal component in the wind fields from 1000 hPa to 500 hPa generates more intensive precipitation.
Filed under Keywords:
Conceptual Models, Synoptic Scale Meteorology, Orography