Doyle Rice

USA TODAY

Heavy rains and life-threatening flash flooding from the remnants of Hurricane Norbert and Tropical Storm Dolly are possible in the Southwest this weekend, the National Hurricane Center warns.

"Excessive rain is likely in some areas with the chance of life-threatening flash flooding," said AccuWeather meteorologist Ken Clark, who adds the floods will be due to the region's rocky terrain, steep hillsides and arroyos. Runoff is often very rapid and can fill the typically dry stream beds.

The bulk of the rain will be centered on Arizona and western New Mexico, reports AccuWeather meteorologist Alex Sosnowski.

In Arizona, "showers and thunderstorms will increase in coverage Saturday and Sunday, with periods for heavy rain both days, and continuing through Monday at many different locations across the region," according to an online forecast from the National Weather Service in Phoenix.

Arizona has seen a wetter-than-normal monsoon season this year; a thunderstorm brought rain, gusty winds and blowing dust to Phoenix and some surrounding areas Thursday night.

Some rain will also reach southern Nevada, southern Utah, southwestern Colorado and part of Southern California, Sosnowski said. Some scattered thunderstorms and locally heavy rainfall could dampen parts of the L.A. Basin and San Diego metro area early next week, according to the Weather Channel.

Eastern Pacific hurricanes seldom affect the U.S., but occasionally a storm's remnants can bring heavy rain to California, the Southwest and sometimes to places as far east as Oklahoma.

Hurricane Norbert is now near the western coast of the Baja Peninsula in Mexico, where hurricane warnings have been issued, the Weather Channel reports. In addition, tropical storm warnings have been extended farther north along the peninsula.

As of 11 a.m. ET, the center of Norbert was located about 140 miles west of Cabo San Lucas, Mexico, and had maximum sustained winds of 90 mph, making it a Category 1 hurricane, the hurricane center reported.

It was tracking to the northwest at 8 mph. A slow weakening is expected during the next 48 hours, the hurricane center predicts.

Contributing: Associated Press