The first winter storm of the season took aim at the Southland Tuesday, threatening "a significant change in weather" in the form of cooler temperatures and measurable rainfall -- but not much of it -- on Wednesday, National Weather Service forecasters said.
The region will experience light rain or drizzle by late Tuesday evening, largely as a result of a deepening marine layer, with more widespread light showers beginning Wednesday morning and persisting through late Wednesday night, according to the NWS.
The cold low-pressure system was developing over the Pacific Northwest today and expected to quickly move southward through Central California Wednesday, then through Southern California late Wednesday through early Thursday, NWS forecasters said.
"A storm system moving south over the West Coast will bring a significant change in weather to southwest California Tuesday night through late Wednesday night," according to an NWS advisory.
The storm "will bring much cooler temperatures to the area, with daytime highs falling into the 70s (today) and into the lower to mid 60s on Wednesday," it said, adding: "This storm also has the potential to bring measurable rainfall to the area, especially over Los Angeles County and southward."
Most areas will get no more than a tenth of an inch of rain, but more than a quarter of an inch could fall in the San Gabriel Mountains and the foothills, according to the NWS.
The unseasonably cold air accompanying the storm -- temperatures will be 15-25 degrees below normal -- will cause the snow level to drop to between 5,500 and 6,000 feet, and light snow is possible at higher elevations Wednesday night, NWS forecasters said.
High winds are expected in some mountain and desert areas, with sustained winds of between 20 and 30 miles per hour gusting to 50 mph and isolated 65-mph gusts possible, they said.
A combination of partly cloudy and sunny skies was expected today, but the forecast for Wednesday was for showers across the region and a temperature drop of several degrees.
The NWS forecast a high of 68 today and 64 Wednesday in Marina del Rey.