What does "RASN" abbreviate in weather conditions?

The abbreviation "RASN" specifically represents "Rain and snow." This term is used in meteorological reports to indicate conditions where both rain and snow are occurring simultaneously. It helps in conveying a mixed precipitation scenario that can significantly affect visibility, road conditions, and overall weather impacts.

Understanding this abbreviation is crucial for air traffic controllers, as mixed precipitation can influence landing and takeoff conditions, necessitating appropriate operational adjustments. The other options, while they may describe weather variations involving rain and snow, do not accurately capture the standard abbreviation utilized in meteorological contexts. Thus, choosing "Rain and snow" aligns with accepted weather terminology, making it the most precise answer.