Southern California's prolonged heat wave is giving way to cooler temperatures across the Southland, ahead of a weekend that could bring rain associated with Tropical Storm Rachel, strong winds, and potentially damaging surf along local beaches.
Extreme heat warnings that covered coastal and valley areas of Orange County expired Thursday evening, according to the National Weather Service. Temperatures are expected to continue falling Friday and Saturday as an approaching low-pressure system brings increasing onshore winds and a return of the marine layer. By Saturday, high temperatures are expected to be 5 to 10 degrees cooler, bringing most areas back to near seasonal averages, forecasters said.
A more dramatic change is expected Sunday as tropical moisture associated with Rachel moves toward Southern California and interacts with an early-season cold upper-level low-pressure system. The exact track of Rachel remains uncertain, but forecasters indicated the storm could make landfall in northern Baja California over the weekend, potentially bringing showers, thunderstorms, and gusty winds to the region.
Rain could begin as early as Saturday evening, with the greatest chances expected Sunday and Monday. Showers could continue through Tuesday. Orange County specifically could experience periods of moderate to heavy rainfall, depending on Rachel’s track, with forecasters warning that heavier showers could produce localized flooding.
“Temperatures will trend cooler Friday into Sunday and there will be an increasing chance of showers and thunderstorms due to moisture from … Rachel,” the NWS said. High temperatures in coastal and valley areas of Orange County are expected to remain mostly in the 70s Sunday through Tuesday, with further cooling possible Monday.
Meanwhile, elevated surf and high tides are expected to create hazardous conditions along beaches in Orange County. A coastal flood advisory will remain in effect through 2 p.m. Tuesday for coastal areas of Orange County. For south- and southwest-facing beaches in Orange County, surf of 3 to 5 feet, with occasional sets reaching 6 feet, is expected Friday. A stronger southerly swell associated with Rachel is anticipated to arrive Sunday, potentially producing surf of 6 to 9 feet before decreasing to 3 to 6 feet Monday and Tuesday.
Forecasters warned that strong rip currents, elevated surf, and unusually high tides could produce coastal flooding and beach erosion, particularly in low-lying areas. Morning high tides approaching 7 feet, combined with large waves and increasing winds, could create the greatest coastal flooding threat Sunday. Winds over coastal waters are also expected to increase Saturday and Sunday, potentially reaching 20 to 30 knots and generating steep, choppy seas hazardous to small vessels.
Forecasters cautioned that the severity of rainfall, winds, and coastal flooding will depend heavily on Rachel’s eventual track and intensity. Showers could continue through Tuesday night, with decreasing clouds and gradually warmer temperatures expected Wednesday.
