6 things to know about Hurricane Hilary as it churns toward Southern California

Hurricane Hilary is an “impressive major hurricane” that is on track to hit Southern California as a tropical storm, a highly unusual event that could bring strong winds and unusual flooding.

Hilary, now off the west coast of central Mexico, has reached sustained maximum winds near 145 mph, a Category 4 storm.

It is expected to be downgraded to tropical storm status by the time it reaches Southern California on Sunday night.

Here are five things you need to know about Hilary:

EXCEPTIONAL: This is the first time the National Hurricane Center has ever issued a tropical storm watch for Southern California.

TIMING: Tropical storm conditions are possible in Southern California by Sunday.

Hurricane conditions are expected in Baja California beginning Saturday night. Heavy rainfall that could result in flash flooding and landslides in Baja California could occur from late Friday through late Sunday.

FLOOD RISK: Southern California could see flash flooding, urban flooding and arroyo flooding, “with the potential for rare and dangerous impacts.”

RAINFALL: Rainfall of 3 to 6 inches, with as much as 10 inches, could occur across portions of Southern California and southern Nevada. “Rare and dangerous flooding will be possible,” forecasters said.

WIND: Tropical storm conditions could begin in Baja California by Friday night and in Southern California starting Sunday. Hurricane conditions are expected along large stretches of Baja California’s western coast starting Saturday night.

STORM SURGE IN MEXICO: Hurricane watches or warnings are in effect for a large stretch of the western coast of Baja California, from Punta Abreojos north to Ensenada. Forecasters warn of “dangerous storm surge” that is “likely to produce coastal flooding.”