California's not done. Three more atmospheric rivers are on the way. - The Washington Post

At slightest 3 different tempest systems, 1 of which appears to beryllium particularly significant, are connected the mode successful the adjacent 7 days. The astir important is anticipated betwixt Sunday nighttime and Monday night, which volition astir apt bring “widespread flooding, damaging winds, and unsafe formation and marine conditions.” according to the National Weather Service. Thereafter, signs constituent to a signifier that volition support the moisture occurrence hose aimed astatine the authorities done astatine slightest mid- to late-January.

“A bid of potent upwind systems volition interaction our country this play into adjacent week,” wrote the National Weather Service serving the Bay Area successful a forecast treatment Friday. “Please enactment existent with forecast updates arsenic determination is simply a nonstop menace to beingness and spot from these impacts.”

While the deluges bring a invited dent to the drought that’s gripped the authorities for years, they’re proving to beryllium excessively overmuch of a bully thing. Flood watches are up for the bluish two-thirds of California, with wintertime tempest warnings successful the Sierra Nevada.

Just past week, astir 81 percent of California was gripped by a “severe” oregon worse drought, according to the U.S. Drought Monitor. That fig has trickled down to 70 percent, but the bigger communicative has been the elimination of the top-tier “exceptional” drought. It’s improbable the years-long drought volition beryllium busted, but a deeper dent successful the shortage is astatine the precise slightest probable.

Twenty-two trillion gallons of water could autumn connected California from the upcoming bid of storms, said Michael Snyder, a meteorologist based successful Seattle.

Atmospheric rivers are constrictive filaments of tropical moisture that tin agelong thousands of miles oregon more. They’re often lone a mates 100 miles wide, but whitethorn beryllium transporting much than a cardinal pounds of moisture overhead each second. Much of that moisture remains arsenic h2o vapor oregon condensate successful the signifier of unreality cover, but immoderate falls arsenic rainfall oregon snow. Unsurprisingly, precipitation totals tin ascent quickly.

Most atmospheric rivers transportation the bulk of their moisture a mile oregon truthful supra the ground. That’s wherefore the top totals of rainfall oregon snowfall are usually recovered successful the higher elevations. Additionally, moist aerial forced up the mountains often cools to its dew point, becoming saturated and ridding itself of excess moisture successful the signifier of dense precipitation.

It’s not antithetic for rainfall rates to attack oregon transcend fractional an inch per hr successful the lowlands, with snowfall rates of 5 inches per hr oregon greater successful the Sierra Nevada.

At the University of California astatine Berkeley’s Central Sierra Snow Lab, 57.9 inches of snowfall person fallen successful the past week, and there’s a batch much to come.

California sees atmospheric rivers each winter; they’re a predominant portion of the West’s cold-season upwind pattern. But it’s been an exceptionally bedewed agelong arsenic of late. San Francisco received 11.6 inches of rainfall during December, including 5.46 inches connected Dec. 31, which was the city’s second-wettest time since 1849.

A contributing origin has been a zonal, oregon westbound to east, pitchy watercourse pattern. That’s maintained a bedewed westerly travel into California. That means that atmospheric rivers, swirled eastbound by low-pressure systems, person been barreling eastbound into California alternatively than slipping northeast into Oregon oregon Washington.

That signifier appears poised to proceed for weeks to come.

Another conga enactment of atmospheric rivers is connected the mode to California. The archetypal whitethorn beryllium modest, but the second, anticipated to get aboriginal successful the workweek, appears to beryllium much formidable.

Event No. 1: Saturday into Sunday

The archetypal lawsuit is really a brace of low-end atmospheric rivers. They’re being tugged into California arsenic they wrapper northward into a duo of dying low-pressure systems respective 100 miles westbound of the Oregon-Washington border.

The archetypal atmospheric stream volition statesman brushing against the seashore of utmost Northern California connected Friday nighttime earlier dropping southbound overnight, aiming astatine the Bay Area arsenic it wanes connected Saturday. By the evening, different pulse of moisture from the 2nd low-pressure strategy volition pivot into the region.

Up to 5 inches of rainfall is expected successful the Coastal Range, with 2 to 3 inches successful the little elevations northbound of the Bay Area. San Francisco whitethorn beryllium connected the fringe of the archetypal episode, but could inactive spot much than an inch of rain. Several feet of snowfall are expected successful the highest elevations of the Sierra Nevada.

Event No. 2: Monday into Tuesday

A much important atmospheric stream — likely a 4 retired of 5 connected the scale from the Center for Western Weather and Water Extremes, which rates this improvement — volition travel successful Sunday evening and proceed into Tuesday. Very dense rainfall is likely, with totals of 2 to 4 inches astatine the coastline and successful the Central Valley. In the precocious terrain, wherever it’s excessively lukewarm to snow, much than 4 inches of rainfall is probable and arsenic overmuch arsenic 8 to 10 inches is possible.

In the Sierra Nevada, 2 to 5 feet of snowfall are expected, chiefly supra 7,000 feet. At the coastline, winds whitethorn gust to much than 55 mph, with 65 mph gusts expected successful upland summits supra 6,000 feet.

“[W]idespread and perchance important flooding is expected,” wrote the National Weather Service bureau serving the Bay Area. “Gusty winds are besides anticipated successful the higher terrain which could bring much trees down, causing powerfulness outages, question issues, and add[ing] to debris successful flooded waterways.”

Although rainfall should gradually easiness connected Tuesday, galore waterways whitethorn swell implicit their banks. “Tuesday is astir apt the time wherever you’ll apt request to support a truly adjacent oculus connected the upwind arsenic the imaginable for wide flooding of rivers, creeks, streams and roadway and municipality flooding volition beryllium astatine its highest during the adjacent week, arsenic each the runoff and dense precipitation comes unneurotic resulting successful a mess,” wrote the Weather Service bureau serving the country astir Sacramento.

Event No. 3: Late adjacent week

A 3rd atmospheric stream volition impact parts of the West Coast precocious adjacent week. While details are hazy, it appears important precipitation is again likely.