Foehn wind environment with strong and gusty winds. Explanations of the foehn warming and drying effect in popular literature or on the web often single out just one causal mechanism (#1 - Condensation and Precipitation - in the below), but there are in fact four known causes (illustrated in the schematic at top right of this page). These mechanisms often act together, with their contributions varying depending on the size and shape of the mountain barrier and on the meteorological conditions, for example the upstream wind speed, temperature and humidity. 1) Condensation and precipitation: When air is forced upwards over elevated terrain,
History of The Weather Channel originally generated only text-based products. Radar imagery was added to the units in June of that year, with graphical backgrounds being introduced in July, making the 4000 the first STAR to be capable of generating graphics and the first to incorporate the channel's logo in the forecast segments. Also in 1990, The Weather Channel began including snow condition reports at five minutes after the hour. Largely considered the height of the classic TWC by enthusiasts, The Weather Channel underwent a major graphical revamp (with the introduction of a new slogan, "Weather You Can Always Turn To") on March 6, 1991.