Southern California rain: 'Storm door' to open later this week

LOS ANGELES - Enjoy the "classically nice weather" across Southern California over the next few days, the National Weather Service warns, because rain returns to the forecast later this week. 

That "unsettled weather" is expected to sweep the region as early as Friday and will last through the weekend, so you may want to rethink your plans if you're doing anything outdoors Saturday and Sunday. 

According to the NWS, a trough will push to the east on Friday, bringing with it a chance of rain that will likely begin in the evening despite cloudy skies for most of the day. 

Rain is expected for the mountain areas of Ventura and Santa Barbara counties. 

Highs are forecast to be in the mid to upper-60s across the coasts and valleys. Downtown LA will have a high temperature of 65 degrees. 

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"The storm door will open up later Friday evening and will usher in a series of impulses from Friday night through Monday," the NWS said in its latest forecast. 

During this time frame, most areas will see rain, but there is a chance of some dry periods in between those impulses, officials said. 

An air quality alert is in effect until Wednesday at midnight for the valleys of Ventura, Los Angles, Riverside, San Bernardino and Orange counties.

Rainfall totals at this time are estimated to be around half an inch to an inch, with local 2+ inches across the south-facing mountain slopes and San Luis Obispo county coastal foothills. 

Snow, on the other hand, won't be much of a factor during this storm, with snow levels currently forecast to be between 7000 and 8000 feet, forecasters said. 

Elsewhere in the U.S., subfreezing temperatures persist across much of the country, leaving millions of Americans facing dangerous cold as Arctic storms left four dead and knocked out electricity to tens of thousands in the Northwest, brought snow to the South, and walloped the Northeast with blizzard conditions that forced the postponement of an NFL game.

An estimated 95 million people nationwide faced weather warnings or advisories Sunday for wind chills below zero Fahrenheit. Forecasters said the severe cold was expected to push as far south as northern Texas while the bitter blast sends wind chill readings as low as minus 70 degrees in Montana and the Dakotas.

The Associated Press contributed to this report.