Parts of Southern California were put under a tropical storm watch for the very first time Friday, as Hurricane Hilary grew to Category 4 strength and was poised to hit the region as a tropical storm as early as Sunday with “significant and rare impacts,” including heavy rainfall that could lead to extensive flooding, forecasters said.
Considered “large and powerful” by the National Hurricane Center, Hilary was about 360 miles south-southwest of Cabo San Lucas, Mexico, Friday with maximum sustained winds of 145 mph as it moved through the Pacific.
The hurricane center said it expects Hurricane Hilary to “still be a hurricane when it approaches the West Coast of the Baja California peninsula Saturday night” but will weaken to a tropical storm before hitting Southern California on Sunday afternoon.
A tropical storm watch was put in place Friday from the California-Mexico border to the Orange-Los Angeles county line, and included Catalina Island, meaning tropical storm conditions are expected generally within the next 48 hours.
When will Hilary hit Southern California?
The storm is forecast to weaken as it approaches Southern California, but parts of the state could see impacts as soon as Saturday, according to AccuWeather meteorologist Scott Homan.
“However, the impacts of the storm will be well ahead of that as lots of moisture gets strung northward into the storm system and then moves north into California,”
San Diego could see rainfall by Saturday evening, while Los Angeles residents could expect rainfall Sunday afternoon, Homan said. He said Los Angeles, Anaheim, Santa Barbara and San Diego could see about 4 inches of rainfall while desert areas like Palm Springs and the Sierra Nevadas face the potential of 4 to 8 inches.
Hilary is expected to weaken into a Category 3 hurricane by late afternoon Saturday, and diminish into a tropical storm by Sunday afternoon.
Hilary forecast to bring heavy rain, flooding to Southern California
Hilary could be the first tropical storm to make landfall in California since 1939, according to federal weather officials. Last year, Tropical Storm Kay doused Southern California with heavy rain and flooding without making landfall.
“The combination of heavy rainfall, the potential for flash flooding and strong winds could very well make this a high impact event for Southern California,” Samantha Connolly, a National Weather Service meteorologist in San Diego, wrote in a Thursday morning forecast.
How much rainfall could Hurricane Hilary bring?
Hilary is expected to bring a risk of flash flooding and heavy rainfall in southern California, southern Nevada and western Arizona, the hurricane center said. Here’s the weather service rain forecast for California, in inches.
The most rainfall ever recorded during the month of August in San Diego was 2.13 inches in 1977, the weather service said Thursday.
Could climate change bring hurricanes to the West Coast?
Hurricanes need two things to stay energized: warm water and favorable winds. The California coast typically benefits from cooler water that flows southward along the coast and winds tend to either shear the tops off hurricanes or push them westward out to sea. Given its history, a hurricane landfall in California is not impossible, but highly unlikely for two reasons: the cold ocean water and upper-level winds.
Scientists aren’t yet sure how human-caused climate change might specifically affect the frequency or intensity of hurricanes.
“Sea surface temperatures are generally rising as the climate warms, which could provide more ‘fuel’ for any hurricanes that do form,” said Kim Wood, an associate professor in the Department of Geosciences at Mississippi State University