A strong October storm system is moving towards Southern California, with forecasts indicating widespread rain, possible thunderstorms, and a heightened risk of localized flooding for Irvine and the surrounding Orange County area. The National Weather Service (NWS) reports that the approaching system could deliver between one and two inches of rain in some locations, with heavier downpours possible as it progresses.
Rainfall is anticipated to begin as early as Tuesday night, though the most significant threat of heavier showers and potential thunderstorms is expected from Wednesday night into Thursday. Current projections suggest most areas will receive closer to an inch of rain over this two-day period, with some specific locations potentially reaching as much as two inches. The NWS noted that "a pretty potent storm for October appears to be headed towards southern California Wednesday and Thursday."
Locally higher totals cannot be ruled out if stronger showers or thunderstorms develop. Peak rain rates of up to .75 inches per hour are considered possible, and a flood watch may be needed. The NWS indicates that the exact timing and total rainfall amounts remain somewhat uncertain. This is attributed to the low-pressure system being partially separated from the stronger jet stream further to the north. Forecasters also point to an increasing risk for scattered convective activity and localized heavy rainfall, particularly overnight Wednesday into Thursday, which could lead to a significant variance in rainfall rates and totals across the region. This latest forecast represents an increased concern about potentially hazardous rainfall compared to earlier projections.
Beyond the rain, the storm is expected to bring a notable drop in temperatures across Irvine. This follows several days of unusually hot weather and powerful Santa Ana winds. Temperatures began a cooling trend over the weekend as offshore winds weakened, with additional cooling expected Tuesday. The NWS reported that temperatures would fall below normal on Tuesday for the first time in several days.
Wednesday and Thursday are predicted to be cloudy and cool. Daytime highs across much of Orange County, including Irvine, are generally expected to be in the mid-60s to lower 70s. Periods of rain and thunderstorms are possible in Orange County as the storm moves through. The NWS does not anticipate snow production below 8,000 feet with this system.
Coastal areas near Irvine could also experience deteriorating marine conditions on Wednesday and Thursday. Rain, thunderstorms, and isolated waterspouts are possible in coastal waters. Forecasters have warned that thunderstorms over the ocean could generate lightning, gusty and erratic winds, small hail, and choppy seas. A beach hazards statement remains in effect through late Thursday night for portions of the Los Angeles County coastline, with elevated surf, dangerous rip currents, minor beach erosion, and tidal overflow possible in low-lying areas, suggesting similar conditions for nearby Orange County beaches.
Following the storm, dry and warmer weather is expected to return to Irvine and the broader region by Friday, continuing into next week. Offshore winds could reappear over the weekend, though any anticipated Santa Ana event is expected to be considerably weaker than the strong winds and unusually hot weather experienced last week. Temperatures could climb into the 80s in some areas over the weekend.
