A disruptive storm packing snow and rain will cross the western United States through Friday.
The storm will act as a double-edged sword for the region, bringing beneficial rain and snow along with the threat for flash flooding and travel disruptions.
Snow and ice left many motorists stranded along the Interstate 5 corridor in Oregon on Wednesday evening.
While the threat for ice will diminish on Thursday, rain and snow will expand farther inland and southward through Friday.
The heaviest rain will fall over northern and central California into Thursday night, including in San Francisco, Sacramento and Fresno. Rainfall could easily exceed 1 to 2 inches in these areas.
Rain will then expand into Southern California.
Los Angeles and San Diego could both receive a thorough soaking. Some rain will even reach the desert areas of Phoenix and Las Vegas.
“Enough rain will fall to cause excess water on the roads, including along the major California highways such as Interstate 5, I-10, I-15 and I-80,” AccuWeather Senior Meteorologist Alex Sosnowski said.
Burn-scarred areas will be especially prone to flash flooding and mudslides from this event.
Snow levels will lower drastically across the Sierra Nevada, falling from above 8,000 feet down to around 6,000 feet by Friday. Over a foot of snow can fall across the highest peaks, which will build up the snowpack and give a boost to ski resorts.
Travelers over Donner Pass should use extreme caution Thursday night. As temperatures drop drastically, rain will change to snow. Wet surfaces can quickly freeze.
The rain and snow will help put a dent in the long-standing drought and replenish low river beds and reservoirs.
The Western states will turn drier but much colder this weekend. A stormy pattern will resume during the week of Christmas, with the bulk of the rain and snow focusing on the Pacific Northwest.