Strong Winds Down Trees, Power Lines

Southern Californians should be on the lookout this afternoon and late tonight for broken tree limbs, downed trees and power lines, and traffic signal outages due to strong northeast winds, the National Weather Service warned.

Weather service forecasters issued high-wind warnings — or the lesser advisories — for today and Friday until 2 p.m. for a wide swath of Southern California including Los Angeles, the Inland Empire, the interior valleys of Ventura County, the Santa Monica mountains, San Diego, San Bernardino and Riverside counties, and many coastal areas.

Wind speeds of up to 50 mph were forecast, with gusts to 60 mph in the mountains, caused by strong offshore flow, the weather service said.

The strongest winds were expected through this afternoon and again late tonight.

The winds, known as Santa Anas, occur usually during fall and winter when cold, dense air moves south from the Gulf of Alaska and acts as a wedge to force the warm air over Southern California aloft, said Bill Hoffer, a National Weather Service spokesman in Oxnard.

Wind speeds should diminish Friday afternoon.