Three more atmospheric rivers headed into Sonoma County. What drives the storm train?

January is often the season for atmospheric rivers in California, however for the reason that New Yr, Sonoma County has had an virtually steady collection of them — an uncommon prevalence, which consultants attribute to the jet stream surging over the Pacific Ocean.

Three extra of those moisture-laden occasions have been actually described as rivers within the sky, being carried by winds towards the Golden State, in response to meteorologists, who count on extra storms to start Wednesday evening.

These storms will proceed by Jan. 20, mentioned Chad Hecht, a analysis and operations meteorologist on the College of California, San Diego’s Heart for Western Climate and Water Extremes.

Whereas the presence of rivers within the ambiance hardly raised alarms amongst climate forecasters, what stood out was that they happen in such fast succession.

The Bay Space usually experiences a couple of dozen atmospheric rivers in the course of the winter, in response to the Nationwide Climate Service’s Bay Space workplace in Monterey. However together with the 2 occasions that occurred after Christmas, the area — and Sonoma County specifically — has already been hit by at the least six of them.

“If I had my want, I wish to publish it additional,” Hecht mentioned on Tuesday.

Atmospheric rivers are brought on by the build-up of moisture over hotter tropical areas. The latter, Hecht added, might have originated as far-off as Guam.

They’ll develop as much as 375 miles extensive and stretch as much as 1,000 miles lengthy, in response to the Nationwide Oceanic and Atmospheric Administration. Winds push them by the ambiance, and the moisture they carry turns into rain or snow as soon as they’re over the bottom.

4 have pounded Sonoma County since Jan. 4, when rain and powerful winds as much as 2 inches wreaked havoc throughout the realm, downing a tall redwood close to Occidental that landed on a cellular house and killed a 2-and-a-half-year-old boy.

A second atmospheric river developed Saturday and in addition dropped at the least 2 inches of rain on this space. On Sunday evening, a 3rd fell greater than 2 inches of rain in Sonoma County earlier than shifting into Southern California, the place it prompted vital flooding close to Santa Barbara.

The river final appeared within the ambiance Monday evening, and by Tuesday night, it had fallen 1⅓ of an inch over Santa Rosa, in response to the Nationwide Climate Service.

Sarah McCorkle, a meteorologist within the Nationwide Climate Service’s Bay Space workplace, agreed that winds had been the dominant think about atmospheric wave ripples.

“That was not regular,” she mentioned.

The following atmospheric river is predicted Wednesday and can carry as much as 3 inches of rain in Sonoma County by Thursday, in response to the Nationwide Climate Service.

One other 2 to three inches might fall over the weekend earlier than small quantities of rain develop early subsequent week.

Precipitation ranges are anticipated to drop as a result of subsequent week atmospheric rivers transfer south alongside the coast, McCorkle mentioned, earlier than turning east over land.

Hecht described atmospheric rivers as a “double-edged sword”.

“It cannot solely be harmful, but in addition helpful as a result of it is among the main meteorological phenomena that provides California with water,” he mentioned.

The U.S. Drought Monitor exhibits Sonoma County nonetheless within the extreme drought class, and Hecht mentioned it is too early to say whether or not the realm has fallen out of the woods after these newest storms.

“With a view to have a standard water yr, you want greater than we have had within the final two weeks,” he mentioned.

You’ll be able to contact the writer, Colin Atagi, at on Twitter: @colin_atagi.

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