[82lsju]

Atmospheric rivers on their way for NorCal, one on Friday, one on Sunday, per NYT. A third will hit midweek, and a fourth affecting SoCal will happen by the end of next week.

Atmospheric Rivers Forecast to Bring Rain to California and The West - The New York Times (nytimes.com)

When did storms, or a series of storms, become atmospheric rivers?

they seem to be the more general terms for weather that locally used to be called "pineapple express" storms

A well-known example of a strong atmospheric river is called the "Pineapple Express" because moisture builds up in the tropical Pacific around Hawaii and can wallop the U.S. and Canada's West Coasts with heavy rainfall and snow.

https://oceanservice.noaa.gov/facts/pine...press.html

[82lsju]

Atmospheric rivers on their way for NorCal, one on Friday, one on Sunday, per NYT. A third will hit midweek, and a fourth affecting SoCal will happen by the end of next week.

Atmospheric Rivers Forecast to Bring Rain to California and The West - The New York Times (nytimes.com)

When did storms, or a series of storms, become atmospheric rivers?

they seem to be the more general terms for weather that locally used to be called "pineapple express" storms

A well-known example of a strong atmospheric river is called the "Pineapple Express" because moisture builds up in the tropical Pacific around Hawaii and can wallop the U.S. and Canada's West Coasts with heavy rainfall and snow.

https://oceanservice.noaa.gov/facts/pine...press.html