Why is the Tri-Counties getting so much rain? It's the combo of storms and atmospheric rivers
The latest storm is the 12th time we've seen this one-two punch this rainfall season
Here we go again! Yet another major storm is hitting the Tri-Counties.
"This does have a weak atmospheric river tied into it," said Robbie Munroe, who's a meteorologist with the National Weather Service in Oxnard. "Unlike some of the previous storms we've had this winter, this storm is coming from the Southwest, so Southern Santa Barbara County and Ventura County could get more rain than the Central Coast."
It’s been a banner year for systems which mix traditional winter storms from the Gulf of Alaska with atmospheric rivers. They amplify the rainfall. The storms drag tropical moisture to the West Coast, basically providing the fuel for enhanced rainfall and snowfall.
"Normally every year, we have five or six storms which can also be these atmospheric river events," said Dr. Bill Patzert, who's an oceanographer and climatologist. He spent decades with NASA’s Jet Propulsion Laboratory in Pasadena, studying the impacts of the ocean on weather.
He says we’re seeing an unusual number of these Gulf of Alaska winter storms being amplified by atmospheric rivers. "This year, we're on our 12th atmospheric river."
The researcher is one of the nation’s leading experts on El Ninos, and La Nina weather patterns, which are created by variations in ocean water temperature. El Ninos can open the door to much wetter winters, and springs that usual. La Ninas can have the opposite effect.
And sometimes, we’re sort of in the middle, where neither one plays a big role in the Tri-Counties weather pattern.
We’ve been in La Nina mode for the last few years. But, Patzert says those who thought it would influence this winter ended up with egg on their faces. The La Nina is waning, and he doesn't think there is enough time for an El Nino pattern to set up to influence this coming winter's weather.
But, the rainfall statistics for the region this season have been impressive. Most areas are between 175% and 225% of their normal average rainfall.
Ojai has had 36” of rain, Ventura 24”, Santa Barbara 32”, Lompoc 30”, and San Luis Obispo 43”. If you want to really be impressed, Rocky Butte, which is in the mountains northwest of San Luis Obispo, has recorded 89 inches of rain this rainfall season.
But, Patzert cautions this strong rainfall season isn’t enough to be a drought-buster. Some of the reservoirs which feed California still aren’t full. And, he says one good year can’t replenish underground water basins which have been overdrawn for years.
He said what were seeing is drought relief, but not a drought buster.
But, we could get more help in the rainfall department. This storm is expected to bring 1-3" of rain to the coast and inland, and 3-6” in the mountains. And, Munroe says we could see even more rain before the end of the month.