A high surf advisory has been issued for Friday morning and afternoon, with beach erosion possible, the National Weather Service warned in a storm update on Thursday.

“The remainder of the previous forecast remains unchanged as a large swell train is expected to reach the Washington coast on Friday, creating high surf conditions,” the new advisory said.

The advisory is for the north and central coast, and, “There is high confidence that large waves will impact the coast.”

Swells from the west swells of 20-23 feet could cause possible beach erosion near Ocean Shores and Westport, the Weather Service said. The largest waves will arrive Friday morning or afternoon. Seas will subside under 20 feet Friday night.

The Weather Service’s Seattle office issues a warning for dangerous beach conditions and urged “extreme caution near beaches.” Large waves are expected to run farther up the beaches, possibly carrying damaging debris such as large logs.

River flooding danger also remained high, with flood warnings issued for the Bogachiel River near La Push in Clallam County and the Skokomish River near Potlach in Mason County.

Moderate to heavy rainfall over the Olympics is expected to continue overnight. The Weather Service warns drivers not to drive through any flooded area.