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
Weather spotting Weather spotting Weather spotting is observing weather for the purpose of reporting to a larger group or organization. Examples include National Weather Service (NWS) co-op observers and Skywarn storm spotters. A storm spotter is a specific type of weather spotter. In the U.S., these volunteers are usually trained by the National Weather Service or local Skywarn group, and are given a phone number, internet outlet, or amateur radio frequency to report to if a severe weather event, such as a tornado, severe thunderstorm, or flash flood occurs where the spotter is located. They add ground truth information to remote sensing