Three storms will hit California and the southwestern United States into early next week with travel disruptions from flooding and mountain snow.
While the rain will not come at once, each storm will be packed with moisture and will lead to travel difficulties for motorists and potential delays for airline passengers.
Flood threat to extend to Southern California, Desert Southwest
Complications from heavy rain will extend well beyond that of northern California into early next week.
Travel along much of Interstate 5 and California Highway 99 will be slow and slick with poor visibility adding to the challenge.
As each storm presses inland from the Pacific Ocean, flooding can occur in portions of California, Nevada, Arizona, New Mexico and Texas.
This includes the likelihood of urban flooding in cities of San Francisco, Los Angeles, San Diego, Sacramento and Palm Springs, California, as well as Las Vegas and Phoenix.
Along with the threat of flash and urban flooding will be the potential for mudslides and other debris flows in the canyons and mountainsides. Flooding will not be limited to recent wildfire areas.
Renewed stream and river flooding is likely in northern California. Due to the high water levels in streams and containment areas, flooding could be worse with this round of storms, compared to that of last week.
Cumulative rainfall will range from 2 to 5 inches in coastal Southern California to 3 to 8 inches in northern California through Monday.
There is the potential for a foot of rain to fall along the slopes of the Coast Ranges and the lower elevations of the Sierra Nevada and southern Cascades.
In the deserts, a general 0.50 to 1 inch of rain is likely. A significant amount of of rain can occur in few short bursts.
"The third storm of the trio will likely have the heaviest precipitation, due to its slow movement and a direct conveyor of moisture into Southern California and the Southwest U.S.," according to AccuWeather Senior Meteorologist Brett Anderson.
Snow could close mountain highways
In addition to the heavy rain, heavy snow will fall on the mountains in the region.
Each storm will bring the potential for 1 to 2 feet of snow over the high country.
"Ski resorts in the southern Sierra Nevada could pick up as much or more snow than northern areas with this storm train setup," AccuWeather Meteorologist Jim Andrews said.
Along I-80, over Donner Pass in California, a foot of snow can fall with each storm with snowfall rates of 2 inches per hour at times. Snowfall of that intensity make roads impassable.
Snow levels will trend lower with each storm into early next week. In addition to wintry travel along I-80, stretches of I-5, I-15 and I-40 could be a challenge.
Enough cold air may settle in to bring a bit of snow to the passes of Southern California during the second storm during Friday night into Saturday.
"Snow levels could drop to around 4,000 feet by Friday night," Anderson said.
The final storm in the series, spanning Sunday night to Monday, has the greatest potential to bring a few inches of snow and slippery travel to Tejon Pass and Cajon Pass.
"Motorists heading over the Grapevine should be prepared for major travel delays Sunday night into Monday," Anderson said.
The series of storms will unload heavy snow in a few doses over the mountains of Arizona, Utah, New Mexico and Colorado as well.
"From 1 to perhaps 3 feet of snow may be on the ground in the mountains of Arizona, including Flagstaff, by late Tuesday," Anderson said.
Gusty winds may topple trees, cut power
While the storms are not likely to bring widespread high winds to the Southwest, winds can be strong enough to knock over a few trees where the ground is saturated. Sporadic power outages can also occur.
Strong gusts will occur over the ridges and passes with each storm and could pose a challenge for high-profile vehicles whether snow is falling or not.
More drought relief in store for California
Prior storms eliminated drought in northern California in recent weeks, according to the United States Drought Monitor. And this latest storm train will have significant positive impact on the drought in Southern California
In the short term, rain will continue to run off into streams and reservoirs.
During the spring and summer, melting snow from the high country will continue the flow of water into aqueducts and deep into the ground.
At the very least drought severity will gradually diminish with each storm into early next week.