First tropical storm watch in history issued for California over Hilary

A tropical storm watch has been issued for Southern California for the first time ever as Hurricane Hilary turns north and threatens the southwest U.S. with heavy rain and high winds.

The tropical storm watch is in effect from the U.S.-Mexico border to the southern edge of Los Angeles County, meaning all of San Diego and Orange County are under it.

Hilary is currently a Category 4 hurricane with wind speeds of about 145 mph, the National Hurricane Center said. The storm is currently off the coast of Mexico, south of the Baja California peninsula. 

A watch means that a tropical storm is possible within the next 48 hours.

Hilary is expected to continue moving north and make landfall Saturday in Baja California. Mexico has declared hurricane warnings for much of the peninsula.

Forecasters believe the storm will weaken over time and become a tropical storm when it reaches the U.S. late Sunday.

“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. “Rainfall amounts of 3 to 6 inches, with isolated amounts of 10 inches, are expected across portions of southern California and southern Nevada. Rare and dangerous flooding will be possible.”

The hurricane center forecast warns Mexicans and Californians to prepare for extreme rain, flash flooding and high winds in the coming days.

The storm is forecasted to continue moving north once it reaches the U.S., weakening to a tropical depression as it moves through the San Joaquin Valley, possibly reaching as far north as Reno, Nev., by Monday based on long-range forecasts.