Monday December 4
There will be many days of rain coming this month. Looks like we’ll make up for the dry November. Flood issues remain elevated for the next several days. Stay alert when out and about. Here’s the run down.
Heavy rain returns later today and tonight for OR (already started in NW WA, BC) and continues through Tue. Wed & Thu will also be quite wet, although the amount of precip will lessen after tomorrow. Cooler air moving in later this week, which will ‘hold’ some of the precip up in the mountains as snow (which is melting fast today & Tue). Inches of precip this week. Best pick for a mostly dry day this week would be Friday.
The coming weekend: more moderate rain on the way Saturday Dec 9 and continuing over much of western WA & BC through Monday Dec 11. Oregon should experience diminishing showers Sunday & Monday, esp south of Salem. Tuesday Dec 12 looks to be the driest day for the entire PNW. Rain returns again Wed Dec 13. Thu will be showery throughout the region.
Friday Dec 15 is trending as the first of several consecutive days of moderate-to-heavy rainfall. This time, colder air will begin to work into the picture, setting up heavy SNOW across the mountains, with a decent amount over the coast range, as well, by Monday Dec 18. We may also see a rain/snow mix at the surface, early the week of Dec 18-22., as the models indicate a cold, moist air mass. We’ll see.
Overall, expect plenty of rain - and flood issues - across the PNW over the first 20 days of December. Models have been quite variable as to timing and location of the heaviest rainfall, but all show a wet cycle. You will hear a lot about atmospheric rivers this month.
Dr. Cliff Mass presents an excellent explanation of “atmospheric rivers”:
“Castles in the air are great until you step out the door.” (--and fall into an atmospheric river. Sorry, couldn’t resist!)
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