Storms packing rain, snow to return to California, northwestern US

A new series of storms will begin along the Pacific Coast of the United States starting late this week and will continue into next week. While the storms may not be intense, they will result in travel problems.

All weather patterns must come to an end, and the setup that allowed warm and dry conditions over much of the Northwest and limited rainfall in California in recent days will wind down to end the week as a new train of storms lines up over the northern Pacific, AccuWeather meteorologists say.

The storm train is not as intense as some episodes over the winter, but with a breakdown of high pressure over the Northwest and a southward shift in the jet stream from the Pacific into North America, there will be more opportunities for rain and mountain snow as well as locally heavy precipitation that can slow travel on highways and airports.

As the initial storm in the series approaches, the first low-elevation rain showers and high-country snow showers will spread across coastal portions of Washington, Oregon and Northern California Thursday night through Friday.

"The heaviest rains will fall near sea level on the coast and into the coastal mountain ranges from southwestern Oregon down through Northern California," said AccuWeather Senior Meteorologist Heather Zehr.

Seattle and Portland, Oregon, will experience rounds of drenching rain Friday and Saturday.

Farther south, rain will fall in the San Francisco Bay area and Sacramento, California, Friday afternoon, but it will take until Saturday, particularly Saturday afternoon, before the first raindrops from the storm hit coastal areas of Southern California, including Los Angeles and San Diego.

"This won't be a major rainmaker in Southern California; totals for the entire event are likely to be 0.50 of an inch or less except for in a few mountain areas," Zehr said.

Enough rain may fall on lower elevations in Northern California to lead to minor episodes of street and highway flooding, AccuWeather Storm Warning Meteorologist Eddie Walker said. Any rain in the Los Angeles area is enough to slow travel.

"Heavier rains will fall around San Francisco with totals of 0.50 of an inch to 1 inch common; some of the higher terrain can see up to 2 inches," Zehr added.

As the first storm progresses inland, temperatures will dip in the Cascades, Siskiyous and Sierra Nevada, where rain will change to snow. Temperatures will fluctuate enough to allow back-and-forth rounds of rain, snow and a wintry mix over the passes in the Cascades this weekend. This will limit accumulations to a small or moderate amount of slush on the roads.

While a blockbuster snowfall is not anticipated in the Sierra Nevada, the change to snow will be more deliberate and add to the snowpack.

"In the higher elevations of the Sierra Nevada, this will be a decent and long-duration snowstorm beginning on Saturday," Walker said, adding, "From this weekend to early next week, 12-18 inches of snow may pile up at the crest of Donner Pass."

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"The highest peaks of the Sierra Nevada will pick up 2-3 feet of snow into early next week," Zehr said.

Given the spread-out nature of the snow over a few days, compared to the intensity of the mega storm at the start of the month, crews will have an easier time keeping up with this storm.

"The passes in Southern California aren't likely to see much, if any, snow, but some accumulation is likely above 5,000 feet," Zehr said.

The state of the Sierra Nevada snowpack was close to the historical average for the date as of March 20, ranging from 114% in the north to 92% in the south, or 101% overall, according to the California Department of Water Resources.

Because of the depth of the snowpack, the water locked up within the snow, additional storms this spring and water levels near full capacity at most reservoirs, AccuWeather experts believe that no water shortages will occur in California into the start of the dry season in 2026.

A second and third storm will roll in from the Pacific late in the weekend to the middle of next week. Both of these systems will focus on Washington, Oregon and Northern California, with low-elevation rain and snow for the passes and high country.

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