An atmospheric river is set up to douse almost the entire West Coast. Raising freezing levels today and tomorrow will aid Thanksgiving travelers the next couple of days, keeping snow off of the major passes. By midnight Monday night, the freezing level in much of Oregon will be above 9,000 feet with freezing levels remaining near 10,000 feet for the Pacific Northwest through Wednesday.
I apologize in advance, I’ll be mentioning rain a lot in this post.
While major highways won’t see snow, there will be excessive rainfall. Weather models indicate that the atmospheric river will funnel a consistent flow of moisture into the Pacific Northwest and northern California until around Sunday when a colder airmass pushes into the region.
Flood alerts are starting to be issued by the National Weather Service. The Seattle office has issued a Flood Watch for their entire warning area. With snow levels raising, heavy rain will fall on areas that have recently received copious amounts of snow. Some flood-prone rivers could be a concern this week. Up to a foot of rain is anticipated in the Olympic Mountains with over five inches expected for the Cascades.
At this time, river models show whatever flooding does occur to
stay in the minor category. Potential rivers at risk are the
Nooksack, Skagit, Snoqualmie White and Skokomish Rivers as well
Enough water will be flowing into Washington and Oregon that nearly a half inch of rain is slated for the Tri-Cities and close to a full inch for Spokane by the end of Wednesday.
For Thanksgiving itself, rain is expected west of the Cascades and Idaho Panhandle with a chance of rain elsewhere in Washington and Oregon. While Thanksgiving may be damp, it will be warm. The I-5 corridor will be in the 60s and other decent sized cities will be in the 50s.
If you plan on going out for Black Friday shopping, be ready for a chance of showers to continue, and they will continue to continue through the rest of the week. Your trip home might be a little bit drier, but you’re still looking at rain showers rather than snow so that’s a plus if you’re crossing the mountains.
If you’re traveling around the country Wednesday, there aren’t really any major problem areas. Florida might have some rain and portions of upstate New York could see snow, but neither of those are going to get anywhere near cataclysmic levels. If you happen to be randomly going to western Maine, there’s a chance of snow there too.
I hope you all have a Happy Thanksgiving! For updated information and forecasts, head over to the WeatherTogether Facebook page.
To check road conditions, head over to my page Road Conditions page. I have a bunch of links to access road information for much of the western United States.
To learn about atmospheric rivers, check out this blog post from Charlie.