More big storms lining up along US West Coast
AccuWeather meteorologists warn that yet another significant storm will roll onshore along the Washington, Oregon and Northern California coasts this weekend, following a moderate storm during Friday night. Each storm, regardless of intensity will boost problems associated with heavy rain, mountain snow and gusty winds, AccuWeather meteorologists warn.
The storms have already produced inches of rain along the coast and the lower west-facing mountainsides. Some of the stronger storms have produced sneaker waves and large surf that have caused significant damage and overwash as far to the south as Central California in recent days.
The most recent storm pushed rapidly inland Thursday night and a lull in precipitation was occurring along the Northwest coast from western Washington to Northern California. However, another pulse of precipitation in the form of low elevation rain and mountain snow will swing in Friday night and push inland on Saturday.
A stronger storm will arrive from the Pacific on Saturday.
The moisture of the second remaining strong storm from late Saturday to Sunday will focus on Northern California and southern Oregon, where a brief atmosphere river or fire hose of rain will set up.
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In the coastal areas and on through the lower elevations of the Siskiyous, from 4 to 8 inches of rain will pour down with an AccuWeather Local StormMax™ rainfall of 18 inches from Friday afternoon to Sunday afternoon.
But even farther north to Washington and south to parts of Central California, a general 1-4 inches of rain will fall, which, on top of recent rainfall, is more than enough to flood some of the short-run streams that flow out of the Olympics, Cascades, Coast Ranges and northern Sierra Nevada. Urban flooding is likely throughout the I-5 corridor.
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Snow levels with the weekend storm in the Sierra Nevada will be significantly higher than with the storm into Friday. That difference can result in unstable snow over intermediate and higher elevations and could lead to a significant risk of avalanches. Farther north, less intense snow will also tend to mitigate accumulations over the Washington Cascades. However, a general 6-12 inches can pile up over the high country in the Oregon Cascades.
Most of the wind associated with the weekend storm will be on its back side. Stiff west winds can allow large swells from offshore to roll onto the coast from Oregon to Northern California in the form of big and potentially damaging breakers.
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Much of the precipitation associated with the storm train will remain north of Southern California for the duration of the pattern.
Because the ground is becoming increasingly wet from storm after storm in the region, it may take less rain to trigger mudslides, rockslides and washouts and less wind to knock over trees, which can block roads and take out power lines.
In between both main remaining storms will be pockets of low-elevation rain and drizzle and mountain snow showers.
In the wake of the weekend storm, a longer stretch of dry weather is possible, especially from Oregon to Northern California. These areas can expect a New Year's Eve and New Year's Day free of precipitation. A storm aiming for British Columbia mostly will allow some rain and gusty winds to return to a portion of the Washington coast by New Year's Day.
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