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Extended Wet Pattern to Bring Multiple Rounds of Snow to the Pacific Northwest, California Through Next Week
Published: February 9, 2019
The pattern that has already brought snow to Seattle twice in the last week will hang on for at least one more week, continuing the succession of stormy systems hitting the West Coast.
This is a familiar pattern that is highlighted by a strong dome of high pressure in the central Pacific Ocean and a dip in the jet stream over the West Coast of the U.S.
Following Winter Storm Maya's snowfall in the Pacific Northwest this weekend, at least two more storms will sweep through the West in the upcoming week.
Here's a general timing for each day in the upcoming week:
- Monday: The first storm will arrive in the Northwest from the Pacific with intensifying snowfall throughout the day. Some coastal rain is expected in western Oregon and northwestern California.
- Tuesday: Snow will continue in the Pacific Northwest and spread inland across the northern Rockies and southward into California's Sierra. Rain may also begin to spread into southern California.
- Wednesday: Snow will move into the Southwest while persisting in the Sierra, Great Basin and parts of the Rockies. Some lower elevation rain is possible from the San Francisco Bay area into Southern California. Moderate to locally heavy rain is possible in Southern California, which may bring flood concerns.
- Thursday and Friday: The second storm will arrive in the Pacific Northwest. Snow or a mix of rain and snow is possible in the lower elevations, with some coastal rain in Oregon and Northern California.
It's too early to know how much snow or rain will fall in these areas, but it will be an active pattern for at least the week ahead.
The pattern that we're currently in is called a negative Pacific/North American pattern (-PNA), and it is known for creating cooler than average conditions over the northwestern part of the country and warmer than average conditions in the Southeast, with the jet stream tucked in between.
Like winter storms Lucian and Maya, these two upcoming storm systems will take tracks from the Oregon or California coasts eastward across the Rockies and northeastward across the Plains and Midwest during the middle to end of next week.
Additional Snowfall Isn't Always a Bad Thing
Seattle picked up 2.7 inches of snow from Winter Storm Lucian and an additional 7.2 inches from Winter Storm Maya as of early Saturday. This is above the seasonal average of 6.8 inches and more snow is ahead.
Portland received 1.4 inches from Lucian and 3.9 inches from Maya as of early Saturday. Portland sees about 4.3 inches in an average season.
When you factor in both rainfall and snowfall, much of the Pacific Northwest is running below average for precipitation this winter. Most of the region has seen 50 to 90 percent of average precipitation since Oct. 1.
Some parts of Oregon and Idaho remain in severe drought, according to the latest U.S. Drought Monitor.
Further south, regions have experienced a bit more precipitation recently.
At the beginning of the year, moderate drought covered more than 75 percent of California, which has dropped to around 10 percent as of Feb. 5. Areas of severe and extreme drought have been alleviated across the state, including in the Carr, Camp, Woosley and Holy fire areas.
The snowpack in the Sierra has benefited from the storms as well and, as of Feb. 5, is above normal.
Parts of Southern California and the southern Sierra have benefited the most by this winter's storms, but flooding has been a concern in the burn scar areas at times.
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