The first major atmospheric river storm to hit the West Coast this season quickly strengthens like a bomb cyclone, hitting northern California and southern Oregon with dangerous winds and heavy rain, kicking off the rainy season. is telling. There may be several days of disruption.
The dramatic bombing and warm temperatures in the Pacific Ocean increased the system’s winds and moisture, and the storm brought life-threatening flooding and sustained heavy rain, strong winds, and large amounts of mountain snow to the northern Bay Area. may cause high waves. , according to the National Weather Service’s Weather Prediction Center.
“Storm rainfall totals could reach 12 to 16.” [inches]”Dangerous flash flooding, rock failures, and debris flows are likely,” the agency said in its latest forecast.
By early Wednesday, strong winds in the area are expected to cause widespread power outages and some tree damage, bringing blizzard conditions across the Cascades, the agency said. Wind gusts Tuesday night reached 130 mph in Crescent City, according to the National Weather Service. The winds knocked out power to more than 500,000 homes in two separate towns on the outskirts of Seattle, and two women were reportedly killed by fallen trees, according to area power companies.
The worst winds are expected to hit across Northern California on Wednesday, but forecasters said their biggest concern is the amount and duration of rain, which is also expected to begin in earnest Wednesday. .
More than a foot of rain could soak the North Bay by the end of the week, and a flood watch remains in place for the North Bay until at least Friday. A second cyclonic storm is expected to interact with the first atmospheric river system, producing even more precipitation and lasting even longer.
“We’re going to need a lot of water,” said Daniel Swain, a climate scientist at the University of California, Los Angeles. These conditions have flipped much of the state “from abnormally dry to abnormally wet,” he said, the latest example of California’s hydroclimatic whiplash. As global temperatures continue to rise, the fluctuations are only expected to become more sudden and dramatic.
On the plus side, the abundant rainfall should help end fire season for much of Northern California.
“This is welcome to some extent. By keeping the ecosystem moist, it keeps us away from fire danger,” said Michael Loyc, a professor of environmental studies at the University of California, Santa Cruz. “On the other hand, good things can pass quickly,” he added.
While the Bay Area itself and areas south of it are not expected to see significant precipitation until Friday, there are growing forecasts that much of the state will see at least some rain by early next week.
But what this superstorm means for the rest of California’s rainy season remains to be seen, but it could be the beginning of a short period of slightly wetter weather.
The National Weather Service’s Climate Prediction Center predicts an increased chance of above-average precipitation across much of California through at least the end of this month, but forecasts extending into mid-December are becoming more clear. do not have. The latest three-month outlook through January shows an equal chance of above- or below-average precipitation.
“It could still be a dry season compared to normal, but it’s too early to tell,” said Roger Gass, a National Weather Service meteorologist in Monterey. “There are really no long-term signs.”
The El Niño Southern Oscillation cycle (ENSO), one of the only long-term forecast measures available to forecasters, remains neutral, meaning the Pacific Ocean is not in a La Niña or El Niño cycle. Officials still believe a La Niña pattern is likely to develop by the end of December. If that happens, it will likely be a “weak and short-lived La Niña,” according to the National Oceanic and Atmospheric Administration’s latest ENSO blog. La Niña years typically favor drier conditions in the southwestern United States. One of the past two wet winters in California was an El Niño year. However, a weak cycle means that its effects can also be minimized.
“Historically, during this weak La Niña event, precipitation has been slightly less than normal,” said National Weather Service meteorologist Brian Lewis in Oxnard. “It’s hard to say that it will continue for the rest of this period, but it looks like there will be periods of rain over the next week or so.”
Lewis said it looks like another low-pressure system could impact California by Thanksgiving weekend, but it’s too early to know where and how much rain it will bring. He also pointed out that short-term storms alone are not enough to indicate what the entire winter will be like.
But California Water Watch says water officials are taking everything they can get from the storm, and after a hot, dry fall, the state’s precipitation is on track for the current water year (October 1). This is below the average for the 12-month period starting on March 31, 2019.
“Rainfall over the next few days will be extremely beneficial for California’s snowpack in the spring and late summer of 2025,” David Lizard, manager of the California Department of Water Resources’ Division of Hydrology, said in a statement. said. “For California to benefit from spring and summer snowmelt, it must have enough rainstorms in the fall and early winter to wet mountain soils so that additional spring and summer snowmelt is not lost to the soil through runoff. I need it.”
Flood watches remained in place across the North Bay until late Friday, with the National Weather Service warning that some high-elevation areas could see up to 10 inches of flooding by Thursday. In addition to that, another 2 to 4 inches of rain is possible Friday and Saturday. Large portions of Mendocino and Lake counties, as well as parts of the Sacramento Valley, are also under flood watch through Friday, with concerns for “an extended period of moderate to heavy rain,” the weather service warned.
Northern California mountains, including Shasta County and the Sierra Nevada, could see up to 20 inches of snow at elevations above 4,500 feet, with some areas seeing peaks Wednesday, according to a winter storm warning for the region. Can reach 4 feet.
The chance of heavy rain is steadily increasing in Southern California, with forecasters now confident the region could see measurable rain this weekend and early next week as the storm moves south. I am doing it.
“We think it’s going to be more beneficial rain,” Lewis said, adding that while it may help alleviate some of the fire concerns, it may not completely eliminate those concerns. pointed out that it was high.
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