Storm duo to wallop West Coast with rain, mountain snow and wind
A pair of storms--likely the strongest in a train-- will affect areas from Central California to Washington and British Columbia with the risk of flooding rain, blizzard conditions and damaging winds to end this week.
A pair of storms rolling ashore at the end of the week into the weekend have the potential to trigger significant power outages and travel problems from California to Washington, AccuWeather meteorologists say. One storm will precede the duo, and more are likely to follow.
Two storms will move ashore roughly at about the same time Saturday local time--one will move into Northern California and the other into Vancouver Island, British Columbia. Both storms will be rather potent, packing strong winds and heavy precipitation, but will likely fall short of becoming bomb cyclones.
Heavy, wet, clinging snow that can weigh down trees and lines will increase the risk of power outages in the Sierra Nevada.
"Winds can become strong enough in portions of Northern and Central California and western Washington and southern British Columbia to trigger local to regional power outages," AccuWeather Senior Meteorologist Adam Douty said.
Wind gusts averaging 40-60 mph are likely along the coast and in the mountains of Northern and Central California, as well as in western Washington and British Columbia through Saturday. Higher gusts between 60 and 80 mph are possible in the Sierra Nevada as the southern storm may be more potent than the northern storm. Top gusts over the ridges and peaks in the Sierra Nevada may exceed 100 mph. Breezy conditions with only sporadic wind problems are likely over much of Oregon.
A firehose effect of moisture is likely to be aimed at portions of Northern and Central California. Snowfall rates up to a few inches per hour can occur in the northern Sierra Nevada and Siskiyous through Saturday, where several feet of snow will pile up over the high country and a general 1-3 feet of snow likely over the passes.
"Snow levels may be above the passes briefly at the onset but then drop significantly," Douty said.
Thunder and lightning can accompany the snow with blizzard conditions. The combined effects from snow and wind with the storm in parts of California may force roads to close for a time over the higher elevations.
"Rain will pour down in low elevations in Northern California and the southwestern part of Oregon as well from Friday through Saturday," Douty said.
From 4 to 8 inches will fall on the western and southern-facing slopes of the Coast Ranges, with 2-4 inches in store starting near San Francisco to Redding and just east of Sacramento.
Rainfall totals of 1-2 inches are likely over the rest of the low elevations of Central California. Where the heaviest rain falls, there will be a risk of mudslides, other debris flows and slides and road washouts. Motorists should be prepared for flooded roads in locations that typically drain poorly.
In much of Southern California, winds will be light compared to the action up in the central and northern parts of the state with the storm this weekend. Still, breezy conditions may hamper fire-fighting efforts for the Franklin Fire.
The Franklin Fire spread to more than 4,000 acres on Dec. 11, with less than 10% containment.
Little to no rain is likely in Southern California from the storm farther north in the state this weekend.
Meanwhile, the storm forecast to affect the Northwest will bring locally heavy rain and high country snow to western Washington and southwestern British Columbia from Friday to Saturday.
The strongest winds are likely from the western slopes of the mountains to the coast in Washington and southern British Columbia, where power outages are most likely with the northern storm.
Enough rain can fall in low elevations of Washington to lead to sporadic urban flooding problems. From 6-12 inches of snow is likely to fall over the Cascades. Much heavier rain and mountain snow are likely to fall on British Columbia which could result in more significant urban flooding in Vancouver and the risk of temporary road closures in the mountains.
Additional storms will roll in from the Pacific Ocean after the duo through Saturday. However, there may be another break in the action later next week instead of the storm train running longer.
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