Tropical Storm Rachel is expected to make landfall near the U.S.-Mexico border Saturday, Oct. 10, bringing rain, high surf and coastal flooding to Encinitas beaches through Tuesday, Oct. 13.

The National Weather Service issued a tropical storm watch for San Diego County on Friday, Oct. 9, covering the coast, valleys, mountains and deserts. It is only the second tropical storm watch ever issued for Southern California, The Weather Channel reported. The first came ahead of Tropical Storm Hilary in August 2023.

As of noon Friday, Rachel was about 800 miles southwest of San Diego with maximum sustained winds of 50 mph, according to KTLA, citing the National Hurricane Center. The NWS said it has high confidence that coastal flooding will be significant.

NWS forecaster Miguel Miller told the San Diego Union-Tribune that Rachel will produce 6- to 10-foot waves along the coast, especially at southwest-facing beaches. Surf is expected to reach 5 to 7 feet Sunday, Oct. 11, with some sets as high as 9 feet.

Morning high tides near 7 feet, combined with the swell and wind-driven waves, are expected to worsen the threat of coastal flooding and beach erosion, the NWS said. A coastal flood advisory is in effect through 2 p.m. Tuesday, according to NBC 7 San Diego.

Rain is expected from late Saturday night through roughly noon Sunday. A second low-pressure system arriving Sunday night could extend showers into Monday and Tuesday. The coast could receive 0.75 to 1 inch of rain total, with mountains seeing about 1.5 inches, according to NWS forecasters cited by the Union-Tribune.

Tropical storm-force wind gusts of at least 34 mph are expected Sunday, arriving as early as Saturday night, the Times of San Diego reported. The NWS warned that large tree limbs may break off in coastal and valley areas, and strong winds could capsize or damage vessels.

San Diego lifeguards are staffing up. Lt. Charlie Knight, a marine safety lieutenant for San Diego Fire and Rescue, said in an Oct. 6 CBS 8 report that crews were "upstaffing and putting more lifeguards on the beach for those conditions."

City of San Diego crews will also monitor locations with a history of flooding and place warning signs, CBS 8 reported Friday.

Weather scientist Daniel Swain noted that ocean temperatures in Rachel's path are more than 10 degrees above average, according to the Times of San Diego. Scripps Institution of Oceanography measured 73-degree water at the Scripps Pier on Friday, tied for the hottest temperature ever recorded on that date. The warm water could allow Rachel to restrengthen to sustained winds of 60 to 65 mph before landfall, Swain said.

Encinitas-area residents in ZIP codes 92024 and 92007 can search for nearby sandbag locations through 211 San Diego at 211sandiego.org/el-nino, as we reported Oct. 8. Free sandbags are also available countywide at locations listed at ReadySanDiego.org. Residents can sign up for emergency alerts at AlertSanDiego.org.