NWS extends SoCal flood warnings through Friday as tides peak

The National Weather Service extended flood advisories for all Southern California coastal counties through 2 p.m. Friday on Wednesday. This extension keeps safety protocols in place beyond the original expiration time of 1 p.m. Thursday. Meteorologist Devin Black of the NWS Oxnard office confirmed the change in status.

Orange County and San Diego County will shift from a higher-severity flood warning to a coastal advisory. These two counties were under the stricter warning through Thursday afternoon. The downgrade reflects the forecast for decreasing water levels over the weekend.

High tides have already flooded low-lying areas in several coastal communities. Black reported that seawater has covered streets and reached the bases of some buildings. The Balboa area of Newport Beach experienced widespread flooding earlier this week. Sunset Beach also suffered street flooding, and Pacific Coast Highway is currently closed. Caltrans plans to close portions of that highway again on Thursday.

Long Beach has been the primary area of concern for several weeks. Tides are expected to reach 8 feet Thursday morning before gradually receding. Black noted that some tides this week broke local records, describing them as extreme.

The risk varied by location due to swell direction. San Diego and Orange counties faced higher risks because they are more exposed to southwesterly swells. Black stated that the angle and magnitude of the swells are major factors in the flooding intensity.

The current weather patterns involve a mix of astronomical events and unusually warm ocean waters. Scientists attribute the high sea levels to a combination of climate change, an El Niño-fueled Kelvin wave, and a marine heat wave. The marine heat wave has raised seawater levels by 1.25 to 1.8 feet above normal moon-and-sun driven tides.

Mark Merrifield, director of UC San Diego’s Center for Climate Change Impacts and Adaptation, predicted these conditions during a town hall months ago. He described the forecast as likely the highest sea levels ever recorded on the California coast for this event. Merrifield warned that flooding would be a major issue for the winter season.

Higher tides are expected around the Thanksgiving, Christmas, and Martin Luther King Jr. Day holidays. A strong storm arriving during these high-tide periods could cause severe flooding. A similar scenario occurred in late January 1983, when a storm hit during strong El Niño conditions and high tides, damaging piers along the coast.