A storm out of the Pacific Northwest was headed toward Southern California Friday, packing the potential to generate showers and snow as low as 3,500 feet throughout the weekend.
Hazardous driving conditions are possible in mountain areas and along the 5 and 14 freeways north of Los Angeles, where drivers might encounter blowing snow and icy roads.
In foothill communities, thunderstorms might trigger debris flows. The concern is particularly high in areas below recent brush fire burn areas, such as Glendora in the San Gabriel Valley.
The system will move into Southern California late Friday and continue to drop rain and snow through Monday, according to the National Weather Service.
"There will be periods of rain all weekend long," said NBC4 forecaster Crystal Egger. "We're looking at the possibility of thunderstorms Saturday and Sunday."
Cloud cover will increase Friday afternoon with scattered showers developing in mountain areas.
The NWS issued a winter storm watch for the San Gabriel Mountains from Saturday afternoon through Monday afternoon because of the possibility of snow, blowing snow, lightning and poor visibility -- a quarter-mile or less. The advisory indicated between 8 and 16 inches snow could accumulate above 5,500 feet by Monday morning.
Temperatures will remain mainly in the 60s for several days, with a slight warming trend beginning Thursday in some communities.