Southern California’s prolonged heat wave is giving way to cooler temperatures across the Southland beginning Friday, 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 Los Angeles and Orange counties expired at 8 p.m. Thursday, according to the National Weather Service.
Temperatures will 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. While the exact track of Rachel remains uncertain, forecasters said 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. The National Weather Service said rainfall totals in Los Angeles County are most likely to range from a tenth to a quarter-inch, with locally higher amounts possible in the mountains. Orange County could experience periods of moderate to heavy rainfall, depending on Rachel’s track, with forecasters warning that heavier showers could produce localized flooding. The National Weather Service indicated that "temperatures will trend cooler Friday into Sunday" with an increasing chance of showers and thunderstorms due to moisture from Tropical Storm Rachel.
High temperatures in coastal and valley areas of Los Angeles and Orange counties are expected to remain mostly in the 70s Sunday through Tuesday, with further cooling possible Monday as another low-pressure system moves into Southern California.
Meanwhile, elevated surf and high tides are expected to create hazardous conditions along beaches in both counties. A coastal flood advisory will remain in effect through 2 p.m. Tuesday for coastal areas of Los Angeles and Orange counties. In Orange County, surf of 3 to 5 feet, with occasional sets reaching 6 feet, is expected Friday along south- and southwest-facing beaches. A stronger southerly swell associated with Rachel is expected 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. Los Angeles County beaches could also experience significant impacts, with forecasters saying a coastal flood warning may become necessary in southern portions of the county if high tides, swells, and strong winds coincide.
Winds over coastal waters are 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.
