Hurricane Hilary grew rapidly to Category 4 strength off Mexico’s Pacific coast on Friday and could reach Southern California as the first tropical storm here in 84 years, causing “significant and rare impacts” including extensive flooding.

The U.S. National Hurricane Center has issued a tropical storm watch for Southern California, the first time it has ever done that.

Hilary had sustained winds near 145 mph early Friday, and was expected to strengthen a bit more before starting to weaken. It nevertheless was expected to still be a hurricane when approaching Mexico’s Baja California peninsula on Saturday night, and a tropical storm when approaching Southern California on Sunday.

A flood watch is slated to be in effect for much of Ventura and Los Angeles counties, including in Long Beach, from Sunday afternoon through Monday evening, according to the National Weather Service. The storm will also bring high winds, heavy rains and increased swells to Long Beach, according to city officials.

No tropical storm has made landfall in Southern California since Sept. 25, 1939, according to the National Weather Service.

Early Friday, Hilary was centered about 360 miles south-southwest of Los Cabos on the southern tip of the Baja peninsula. It was moving northwest at 10 mph, and was expected to turn further toward the north.

The Mexican government extended its hurricane watches and warnings northward for parts of Baja California peninsula, and also issued a tropical storm watch for parts of mainland Mexico.

“Heavy rainfall in association with Hilary is expected to impact the Southwestern United States through next Wednesday, peaking on Sunday and Monday,” the hurricane center said. It said there was a substantial danger of flash flooding in an area stretching from San Diego to Las Vegas.

“Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 inches, are expected across portions of southern California and southern Nevada, which would lead to significant and rare impacts. Elsewhere across portions of the Western United States, rainfall totals of 1 to 3 inches are expected.”

SpaceX delayed the launch of a satellite-carrying rocket from a base on California’s central coast until at least Monday. The company said conditions in the Pacific could make it difficult for a ship to recover the rocket booster.

The Mexican government said a weakened Hilary might skim a sparsely populated area on the western edge of the Baja peninsula early Sunday, and then perhaps hit a more heavily populated area of the coast Sunday night between the cities of Playas de Rosarito and Ensenada, in Baja California state.

In Long Beach, officials have advised residents of areas that have historically been prone to flooding to begin preparing now by sealing or using sandbags to protect low-lying areas.

Empty sandbags are available at all neighborhood fire stations in the city, and sand and sandbags are available at:

  • Station 7 (2295 Elm St.)
  • Station 12 (1199 Artesia Blvd.)
  • Station 13 (2475 Adriatic Ave.)
  • Station 14 (5200 Eliot St.)

Residents can also pick up sandbags and sand at the Lifeguard Station located at 72nd Place and Ocean Boulevard at the end of the peninsula.

The Associated Press contributed to this report.

The Lash of St. Francis whipped the shores of Long Beach 80 years ago