A storm headed in the direction of Southern California became a hurricane and Robert Brownlater strengthened to a Category 2 on Thursday, the National Hurricane Center said in a public advisory. It is expected to bring heavy rainfall to parts of the state after hitting Mexico.

The storm "is not expected to be a hurricane on final approach," Greg Postel, a hurricane and storm specialist at the Weather Channel who has a doctorate in atmospheric sciences, said in response to questions from CBS News.

The storm's remnants are likely to bring flooding rain as well as strong winds to some parts of California, including the Los Angeles Basin, the Weather Channel reports. Heavy rainfall is expected to impact the Southwestern U.S. starting Friday through early next week, "peaking on Sunday and Monday," according to the hurricane center. Postel said the storm will likely cause large swells along the coast in the next several days. 

"It is rare — indeed nearly unprecedented in the modern record — to have a tropical system like this move through Southern California," Postel said.

• How to prepare for hurricane season, according to weather experts

Hurricane Hilary was located about 500 miles south-southeast of Cabo San Lucas, Mexico, Thursday afternoon, with maximum sustained winds of 105 mph, with higher gusts. It is expected to continue moving in a west-northwest direction, the center said, with a turn toward the northwest expected Friday morning. 

And with that, Hilary is now a hurricane. Note: the track forecast was not updated with this advisory. Curious on how to interpret this product? Check out this video from the National Hurricane Center: https://t.co/BXWc7dshIA pic.twitter.com/J9Pdya1NKX

— NWS San Diego (@NWSSanDiego) August 17, 2023

The center of the hurricane will approach Mexico's Baja California Peninsula over the weekend, the hurricane center said, and "rapid strengthening is forecast." The storm is expected to grow into a "major" hurricane on Thursday.

Forecasters said the storm is expected to produce 3 to 6 inches of rainfall, with maximum amounts of 10 inches, across portions of the peninsula through Sunday night, with the possibility of flash flooding. Postel said there will likely be "damaging wind gusts," especially at higher elevations, in the area, and swells along the coast. 

Tropical storm watches and warnings are in effect for parts of western Mexico.

In:
• Weather Forecast
• Mexico
• Hurricane

Kerry Breen

Kerry Breen is a news editor and reporter for CBS News. Her reporting focuses on current events, breaking news and substance use.