Atmospheric river set to soak West Coast

An atmospheric river is set to soak the West Coast this week, according to the National Weather Service (NWS).

A "plume of moisture will move over parts of the Pacific Northwest, producing areas of light rain over the Northwest on Tuesday,” the NWS’s Weather Prediction Center said in a forecast discussion Tuesday.

“On Wednesday, a more robust plume of moisture will move over California ahead of a front moving onshore late Wednesday afternoon into Thursday,” the discussion continued. “The moisture will create heavy rain over California.”

The Weather Prediction Center said it has issued a "Slight Risk of excessive rainfall" over parts of Northern and Central California, from Wednesday into Thursday morning, due to the heavy rain in the Golden State.

The rain will leave urban areas, roads, small streams and burn scars most vulnerable to mainly localized flash flooding, according to the NWS.

The Weather Prediction Center warned of an anticipated atmospheric river to begin hitting the West Coast as soon as Tuesday evening, which could build as Wednesday goes on, according to a Monday forecast discussion.

“A combination of strong dynamic forcing as well as a deep, anomalously high stream of moisture moving into southwestern Oregon and northern California will lead to very heavy rainfall, with totals of several inches possible,” the forecast discussion read.

An atmospheric river dumped record-breaking rain on a portion of the Pacific Northwest in December. Conditions in Washington caused passenger rail stations, schools and roads to close. The Evergreen State also saw daily rainfall and temperature records broken.

Amid flooding at the time, a U.S. Coast Guard helicopter rescued a man from the roof of his truck and rescued several others trapped inside a house with 4 feet of water surrounding it, The Associated Press reported.