11pm Wednesday…This first half of November has been extremely wet to the north and west of the Portland metro area. Here in Portland precipitation has been about average and a bit below normal (so far) in southern Oregon.
Those Washington and coastal rain totals have been amazing. 11″ at Olympia just a little past halfway through the month…
But things are about to change…I think splitting systems and upper-level ridging nearby will be the dominant theme for the next 10 days.
Next week (Thanksgiving Week!) ridging to our northwest will allow a surge of colder air to slip south. That happens Tuesday and Wednesday. Models earlier today were VERY cold, and I didn’t jump on that right away. This evenings runs of the GEM, ECMWF, & GFS are a bit more reasonable with a very chilly, but mainly dry pattern most of next week. You get the general picture here:
Is it cold enough that we could see snow? Possible, but as of now I’d lean towards scattered showers Tuesday and/or early Wednesday and then just turning mainly sunny and cool heading into Thanksgiving. That’s definitely subject to change since we’re talking about something 6-7 days away, thus the reason I’m not all excited about it yet.
By the way, the 15 day ensemble charts from the GEM/GFS/ECMWF all show the ridging developing early next week hangs around for the next two weeks, but flopping more right over us or just north. Here are the 500mb height anomaly maps for around December 3rd…two weeks from now. Click on each for a larger view:
The good news is that the weekend looks really nice with abundant sunshine, comfortable days, and chilly nights! We should see the most widespread frost so far over the weekend.
Chief Meteorologist Mark Nelsen