A storm sweeping in from the Pacific Northwest is expected to bring heavy rainfall and the threat of thunderstorms to Long Beach through Tuesday evening, according to the National Weather Service.

Rainfall could begin as early as Monday afternoon, but the heaviest stretch of precipitation is expected to arrive early Tuesday morning, forecasters said.

Long Beach is expected to receive roughly three-quarters of an inch of rain through Tuesday night, forecasters said.

There is also a 20% chance of thunderstorms throughout Long Beach from Monday night through Tuesday evening, with wind gusts expected to reach up to 20 mph blowing south and southeast.

Long Beach was not included in a flood watch issued by the NWS, but Los Angeles, Anaheim, Garden Grove and Downey were all under flash flood watch through Tuesday afternoon.

The National Weather Service warned that mudslides and roadway flooding could occur in and around recent burn scars, including near the Palisades and Eaton fires that scorched parts of Los Angeles County at the start of the year.

Forecasters said the storm system is expected to move out of the region by late morning on Wednesday.

High temperatures in Long Beach will remain in the high 60s on Wednesday, then warm to the mid-to-high 70s through Sunday.