Big weather shakeup in Southern California this week - here's what to know

Weather Forecast for Monday, Dec. 1

The latest forecast and air quality conditions for the greater Los Angeles area, including beaches, valleys and desert regions.

LOS ANGELES - Brace for a windy week, Southern California!

The National Weather Service (NWS) is warning the region about strong Santa Ana winds and significantly cooler conditions that began impacting much of the area Monday. More blustery conditions are expected later in the week. 

Weather Alerts Issued

What we know:

Santa Ana winds returned to parts of the area on Monday as the jet stream continues to push storms north of Southern California and into the Great Basin.

According to the NWS, today's Santa Ana event wasn't strong, but easterly gusts reached the 40s in the mountains and the 30s at lower elevations, mainly across Ventura County and the northwestern portion of LA County.

The NWS issued a wind advisory that was in effect through 3 p.m. for the Western San Gabriel Mountains and 14 Freeway corridor, where northeast winds of 20 to 30 mph were likely, with gusts up to 50 mph.

A wind advisory was also in place until 3 p.m. for the Santa Clarita Valley, western Santa Monica Mountains Recreational Area, Calabasas, Agoura Hills and the western San Fernando Valley, where gusts of up to 45 mph were possible.
 

Temperatures across the coast and valleys are expected to top out in the mid-60s to lower 70s, which is a much cooler event than the Santa Ana observed last week.

Winds will diminish in the late afternoon today, though some offshore breezes may continue through the canyons into Tuesday morning.

Outside the areas impacted by the Santa Anas, today will be quiet, with some areas of dense fog along the Central Coast and chilly morning lows in wind-protected and interior areas.

What they're saying:

"This is a much cooler event than the Santa Ana last week and temps across (the) coast and valleys should top out in the mid 60s to lower 70s," according to the NWS. "Winds will diminish in the late afternoon but with some offshore breezes through the canyons into Tuesday morning."

Looking Ahead

Timeline:

By Tuesday and Wednesday, an offshore flow will weaken and turn onshore, leading to a cooling trend near the coast. There will be little temperature change across the valleys, the NWS said.

On Thursday, another weak to moderate Santa Ana wind event is expected in the same areas impacted on Monday. 

From Friday through next weekend, temperatures will be on the upswing as a high-pressure system moves into the eastern Pacific, according to the NWS.

La Niña Pattern

Big picture view:

The current weather setup, characterized by Santa Ana winds pushing storms well north, is a "common La Niña set up." 

La Niña is a climate pattern in the Pacific Ocean defined by the cooling of the surface water in the central and eastern equatorial Pacific, which can significantly influence weather patterns globally.

This pattern is anticipated to remain in place at least through the first half of December.