California’s first real bout of rain this season could be the sign of things to come as El Niño flexes its muscle in the Pacific Ocean.
By Natalie Hanson, Courthouse News Service
After a slow start to the rainy season, California is awash in rain and snow as many prepare to travel for the coming holiday.
An atmospheric river event arrived slammed the state Sunday, complete with offshore lightning strikes around midnight. The rains triggered a flood advisory through early Monday morning in some Northern California counties including Alameda and Contra Costa.
The National Weather Service’s Sacramento office reported several isolated thunderstorms early Monday. Farther north, counties near the Oregon border saw a small chance of freezing rain according to the weather service’s Medford station.
The San Francisco Bay Area had received about an inch of rain as of Monday afternoon, particularly south of San Francisco toward Big Sur, meteorologist Crystal Oudit said. The weather service’s Bay Area office said most of the widespread heavier rain from this morning had begun moving east and will cause shattered showers in many regions of the north state into the evening.
More rain will arrive Tuesday and Wednesday mornings, possibly lasting through Wednesday evening. The Sacramento weather office also predicted some isolated thunderstorms and snow at high elevations through Wednesday. Oudit said her office expects between one to three inches of rain to fall across the Bay Area by Wednesday night, particularly in the coastal mountain ranges.
About half of the Sacramento Valley could see at least three inches of rain this week. Although the weather system is relatively warm, snow is expected to fall at 7,500 to 8,000 feet, with at least a 50% chance of more than four inches. The heaviest snowfall could be seen near Lassen Peak, and snow could drop down to 6,500 feet by Wednesday.
“Furthermore, a 15 to 25% chance for isolated thunderstorms will remain possible through Tuesday,” Sacramento meteorologists said in a Monday discussion. “This is the result of increasing moisture to the region, amidst a fairly mild temperatures regime, leading to some weak instability. With any thunderstorms that do develop, gusty winds, brief heavy rainfall and small hail will be the primary hazards.”
For those planning to travel across the state by car over the holidays, Oudit said Californians should watch out for roadway flash flooding — particularly during periods of sudden, heavy rainfall.
After years of drought, California entered the water year drought free. Several late-season storms helped improve the state’s soil moisture, as did lower temperatures, higher humidity and more cloud cover this year.
Scientists say they are cautiously optimistic that there could be a slightly wetter winter in the state’s outlook this year given the formation of strong El Niño conditions, but it is very difficult to predict atmospheric river events and their timing. A rain system expected in mid-November proved to be very light, and December has been trending seasonally dry up to this point, Oudit said.
