An atmospheric river will bring heavy rain and the risk of flooding to parts of the Pacific Northwest this week, meteorologists say.

"The forecast remains on track for a prolonged atmospheric river to usher in several days of heavy rainfall over the Pacific Northwest," the National Weather Service’s (NWS) Weather Prediction Center said in a forecast discussion issued early Monday. "Beginning this morning, rainfall coverage and intensity is expected to increase across coastal Washington and Oregon as a potent slug of subtropical moisture begins to flow inland along a strong Pacific jet," it said.

Flood watches—issued by the NWS when conditions are favorable for flooding —span northwest Oregon and parts of western Washington as of early Monday, with the agency cautioning that flooding

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