SoCal storm to bring rain, hail and waterspout risk after weeks of heat and Santa Ana winds

A Pacific storm system tracking south along the California coast is set to drench Southern California on Wednesday and Thursday, ending weeks of punishing heat and Santa Ana winds with a rapid swing to rain, possible thunderstorms, small hail, and isolated waterspouts — all while crews race to shore up a cracked hillside beneath Pacific Coast Highway near Laguna Beach before the first drops fall.

The National Weather Service is calling it 'a pretty potent storm for October,' with rainfall totals of roughly half an inch to 1.5 inches expected across coastal and valley communities and 1.5 to 3 inches possible in south-facing mountains and foothills. The storm was positioned off the Oregon coast Monday and is expected to move south before turning inland somewhere between central and Southern California on Thursday, according to the NWS.

There's going to be quite a bit from southern Santa Barbara County across Ventura County and most of LA County.— Carol Ciliberti, meteorologist, National Weather Service Los Angeles/Oxnard

At Los Angeles International Airport, Ciliberti said rainfall totals should come in just above an inch, while Oxnard is forecast to receive about 1 inch and Santa Barbara around 1.3 inches. To the south, NWS San Diego meteorologist Sam Zuber said Orange and San Bernardino counties could start seeing rain as early as Wednesday morning, with the storm spreading across the broader region by afternoon and evening. Coastal Orange County and the Inland Empire are each projected to receive around three-quarters of an inch, with parts of northern San Diego County seeing a similar amount. Even downtown San Diego could pick up roughly half an inch over the 48- to 72-hour window, Zuber said.

Wednesday night through early Thursday is when rainfall is expected to be most intense — a period that lines up with the start of the morning commute. Zuber warned that the timing could affect early commuters, saying, 'Unfortunately, that could coincide with some of the earlier people heading to the office Thursday morning on the roads,' and urged drivers to slow down, increase following distance, and allow extra travel time.

The storm carries a 30 to 40 percent chance of thunderstorms, which could produce dangerous lightning, heavy downpours, small hail, and waterspouts that may move onshore as weak tornadoes. The NWS warned that peak rain rates of up to three-quarters of an inch per hour are possible and that a flood watch may be needed. The low-pressure system's partial separation from the stronger jet stream to the north means forecasters are leaving some room for uncertainty in both timing and rainfall totals.

With these types of storms, a lot of times what gets us is shorter term, 15- to 30-minute heavy showers that can deliver a lot of rain in that period of time.— Carol Ciliberti, meteorologist, National Weather Service Los Angeles/Oxnard

The greatest danger beyond the roads is in areas scarred by recent wildfires. Ciliberti said there is a minor risk of flooding and debris flows in recent burn areas, with a 10 percent chance of rainfall rates heavy enough to trigger more significant debris flows near those scars.

The storm's arrival adds pressure to an already fragile section of Pacific Coast Highway near Laguna Beach, where a large crack has opened in the bluff that supports the roadway near Crystal Cove State Park. One southbound lane between Irvine Cove Drive and Reef Point Drive has been shut down by Caltrans. Ahead of the rain, crews have been draping plastic tarps over the hillside, and Laguna Beach City Manager Dave Kiff said Caltrans also plans to place large boulders at the base of the slope and develop a longer-term stabilization plan. How the storm will affect the damaged hillside remains uncertain.

Ciliberti said an approaching full moon will push tides higher, and when combined with elevated surf, that could lead to minor to locally moderate coastal flooding and erosion. According to the NWS, a beach hazards statement covering portions of the Los Angeles County coastline will remain in effect through late Thursday night, with dangerous rip currents and tidal overflow possible in low-lying areas.

Marine conditions are also expected to deteriorate, with thunderstorms over the ocean capable of producing lightning, gusty and erratic winds, small hail, and choppy seas. According to the NWS, snowfall is not expected at elevations below 8,000 feet.

It's a pattern change. It is fall.— Carol Ciliberti, meteorologist, National Weather Service Los Angeles/Oxnard

Both NWS offices framed the swing as normal for October, even if the speed of the reversal feels jarring. Zuber said the pattern is well within the range of what the region typically sees, noting, 'This is not abnormal for this time of year at all.' He added that October marks the point when winter storm systems begin pushing into the area. In contrast to colder winter storms, this one is expected to stay relatively warm — Zuber called it 'just going to be a nice wetting rain.' By Friday the system should clear the region, giving way to drier, warmer conditions over the weekend, with temperatures potentially climbing back into the 80s in some areas and a new round of Santa Ana winds — expected to be considerably weaker than last week's — possibly developing, according to the NWS.

The rapid alternation between extreme heat, dry Santa Ana winds, and drenching rain is part of a pattern scientists call 'climate whiplash' — the swift, extreme transition between opposing weather regimes. The Los Angeles Times noted that while such swings have historically played out over years, the time frame is compressing. The same cycle of wet winters producing grass and brush growth, followed by record heat that turns that vegetation into dry kindling, has been linked to the conditions that drove catastrophic fires in Altadena and the Palisades in January 2025.

Why it matters — The storm's combination of heavy short-burst rain, wildfire burn scars, a compromised PCH hillside, and full-moon tides creates compounding hazards for millions of Southern California residents during the Wednesday–Thursday commute window.

Reported by patch.com, ktla.com, watchers.news, latimes.com, sanluisobispo.com, nbclosangeles.com