Strong October Storm Approaches Southern California Bringing Rain, Flood Risks and Cooler Temperatures
A robust October storm system is bearing down on Southern California, prompting warnings from meteorologists regarding widespread rainfall, potential thunderstorms, and an increasing risk of localized flooding across the region. National Weather Service forecasters reported that the system began turning east and tracking on schedule for an afternoon arrival in Los Angeles County.
Rainfall totals across much of Los Angeles County are projected to average about 1.5 inches, with higher amounts of 2 to 3 inches possible in terrain-enhanced zones and locations affected by thunderstorms. In response to the incoming weather, the National Weather Service issued a flood watch for the Malibu coast and both the eastern and western Santa Monica Mountains. The advisory covers areas including Malibu, Malibu Bowl, Pacific Palisades, and Topanga, taking effect Wednesday afternoon through Thursday afternoon.
Forecasters indicated that models show the highest rain rates in those specific mountain and coastal areas, reaching around 0.75 inches per hour. Malibu city spokesperson Matt Meyerhoff noted that while officials are not overly concerned about excessive runoff hitting the city’s burn scars, preparations are fully underway. The city plans to issue emergency alerts to residents via social media and its official website to warn of the stormy conditions.
National Weather Service meteorologist Bryan Lewis stated that at least some minor debris flow could be expected in the area. Meteorologists are also monitoring potential debris flows near older burn scars from the Palisades and Eaton fires, though because those scars are not considered fresh, heavier rainfall would typically be required to trigger significant flows. Beyond burn scars, forecasters warned that flooding could impact urban zones and poor-drainage areas, with extensive street flooding along with rising waters in creeks and rivers.
As the upper low pressure system moves inland late Wednesday night into Thursday morning, forecasters noted a small chance, calculated at 5 percent or less, of a weak tornado forming.
The incoming storm marks a dramatic shift following several days of unusual heat and powerful Santa Ana winds. Wednesday and Thursday will bring cloudy and cool conditions, with daytime high temperatures generally ranging from the mid-60s to the lower 70s across most of Los Angeles County. Orange County is similarly bracing for cooler temperatures, periods of rain, and possible thunderstorms as the system tracks through the region. Snow levels are expected to remain above 8,000 feet.
Maritime conditions will deteriorate over Wednesday and Thursday as well, with thunderstorms and isolated waterspouts threatening coastal waters. The weather service cautioned that maritime thunderstorms could generate dangerous lightning, gusty and erratic winds, small hail, and choppy seas. A beach hazards statement remains active through late Thursday night along the Los Angeles County coastline, warning beachgoers of elevated surf, dangerous rip currents, and the possibility of minor beach erosion and tidal overflow in low-lying areas.
Across the Inland Empire, San Bernardino and Riverside county residents can anticipate half an inch to an inch of rainfall over the course of the storm. National Weather Service meteorologist Kyle Wheeler reported that Wednesday temperatures would reach the high 70s before dropping on Thursday into the 60s. Forecasters are also watching burn scars in the Inland Empire left by the 2024 Bridge and Line fires, though current rainfall projections are not expected to generate debris flows there. A 15% to 20% chance of thunderstorms is forecast for Wednesday night, which could bring heavy downpours and wind gusts ranging from 40 to 60 mph.
Dry weather is expected to return across Southern California by Friday, paving the way for another round of offshore Santa Ana winds over the weekend. Forecasters noted that the upcoming weekend Santa Ana event will be weaker than the winds experienced the previous week, with projected gusts of 30 to 50 mph, strongest in the mountain regions. Temperatures are expected to rebound into the upper 70s and 80s across most coastal and valley locations by the weekend, with Inland Empire temperatures climbing back to 73 degrees on Friday, 78 on Saturday, and 80 degrees on Sunday.
