An Atmospheric River is meteorological term describing a relatively long, narrow region in the atmosphere with increased concentrations of water vapor – like a river in the sky – that transports most of the water vapor out of the tropics towards the temperate zones. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow.[1][2]
A well-known example of an Atmospheric River is the "Pineapple Express", a strong atmospheric river that is capable of bringing moisture from the tropics near Hawaii over to the U.S. West Coast.1
References
- https://www.noaa.gov/stories/what-are-atmospheric-rivers
- https://psl.noaa.gov/arportal/ NOAA's Atmospheric River Portal