California weather forecast: 1st significant rain of season possible this weekend

LOS ANGELES - Get ready for what could possibly be this season's "first significant rainfall" in Southern California. 

But before then, Santa Ana winds return from Tuesday through Thursday thanks to the atmospheric river taking aim at the Pacific Northwest. Right now the forecast predicts wind gusts will prompt advisories and humidity values will plummet.

According to the National Weather Service, this will bring "significant warming" on Wednesday, while the coasts and valleys will see a couple degrees of warming. 

Keep in mind that the gusty winds, dry fuels, and low humidity will lead to easier fire starts and the potential for rapid spread of new or existing fires for portions of Los Angeles and Ventura counties, as well as southern Santa Barbara County. The only active fire burning in the area is the Mountain Fire in Ventura County, which at last check was 98% contained.

"Thursday will be a transitional day from the dry and windy conditions and to a cloudier and wetter pattern," the NWS wrote in its latest forecast. "The offshore flow will turn onshore and will allow a fairly extensive marine layer cloud pattern in the morning. Skies otherwise will be party cloudy as some mid-level clouds drift overhead."

The period we'll want to look out for is Friday through Sunday, according to the NWS. That's when rain chances will spread to much of the area.

"There is a near 100% chance of rain for the area over the three-day period, but only a 30 to 40% chance for any given 12-hour period," the NWS said. 

This is due to the atmospheric river that will bring a good amount of rain to Northern California and Oregon.

We won't be getting nearly as much rain as the folks further north, according to the latest forecast. About ¾ of an inch of rain for north of Point Conception to a quarter to a half-inch south is estimated. This latest system is also expected to be warmer, so very little to no snow is expected for local mountains.

Rain chances will likely continue into early next week, the NWS said. 

Here are some of the weather alerts in effect for the region:

• Wind Advisory in effect this evening through Monday night for the Ventura and Santa Barbara County mountains and Interstate 5 Corridor
• Wind Advisory in effect Monday afternoon and Monday night for the Santa Clarita Valley, San Fernando Valley, eastern Santa Monica Mountains and the Santa Susana Mountains
• Gale Warning for the southern outer waters late tonight through late Monday night
• Freeze Watch in effect Monday night and Tuesday morning for the coast and valleys