SAN FRANCISCO (KRON) -- A high surf advisory for this week has been extended through 4 a.m. Sunday, according to the National Weather Service. Large breaking waves of 20 to 30 feet are possible along the Pacific Coast, the NWS said. Massive pothole opens up on SB I-880 in Oakland The weather service is recommending that inexperienced swimmers remain out of the water due to "life-threatening surf conditions." People are also advised to stay off jetties, piers, and other waterside infrastructure. Graphic: NWS The high surf advisory comes amid several flood advisories that were issued earlier across the Bay Area and flooding in the North Bay that's closed portions of Highway 12 and Highway 121. Wet winter weather and high surf have been widespread across the region this week. On Monday, a section of the Santa Cruz Wharf collapsed into the ocean and two people were rescued after falling into the surf. A third person self-rescued. Multiple rain systems are expected to move across Northern California Friday bringing periods of rain to the region, according to KRON4 Meteorologist Kathy Trafton. Another round of rain is expected late Friday night into Saturday with dangerous surf and beach conditions expected to last through the weekend.