Foehn wind 3) Mechanical mixing: When river water passes over rocks, turbulence is generated in the form of rapids, and white water reveals the turbulent mixing of the water with the air above. Similarly, as air passes over mountains, turbulence occurs and the atmosphere is mixed in the vertical. This mixing generally leads to a downward warming and upward moistening of the cross-mountain airflow, and consequently to warmer, drier foehn winds in the valleys downwind. 4) Radiative warming: Dry foehn conditions are responsible for the occurrence of rain shadows in the lee of mountains, where clear, sunny conditions prevail. This often leads
Significant weather advisory 58 miles per hour. The product is mainly used by forecast offices located in the National Weather Service's Southern Region Headquarters. A significant weather advisory or warning is not an official National Weather Service product, instead it is issued within a special weather statement. Special weather statements are also used for any type of weather approaching watch/warning/advisory levels. Many NWS offices do not use significant weather advisories, instead issue normal special weather statements mentioning much of the same text used in such an advisory. If severe weather is detected, alerts (mainly a severe thunderstorm or tornado warning) are issued by