Foehn wind there is no precipitation, implies there must be other mechanisms. 2) Isentropic draw-down (the draw-down of warmer, drier air from aloft): When the approaching winds are insufficiently strong to propel the low-level air up and over the mountain barrier, the airflow is said to be 'blocked' by the mountain and only air higher up near mountain-top level is able to pass over and down the lee slopes as foehn winds. These higher source regions provide foehn air that becomes warmer and drier on the leeside after it is compressed with descent due to the increase in pressure towards the surface.
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