Okay, maybe ONE more time it's going to snow in Portland…that would be this evening.
The setup is back once again. We've been expecting a good dose of moisture to move in around sunset at the latest here in the western valleys. And we've been expected the south wind to pick up about the same time (or soon after). When I left work Friday, it appeared that snow might briefly stick as low as 1,000' this evening, especially up in Clark/Cowlitz counties and below that elevation in the Gorge.
But one thing has changed in the last 24 hours…colder and drier air has been blowing into the region out of the Columbia River Gorge. More than anticipated. A good chunk of the Columbia Basin to our east is snow-covered and they just had a clear/cold night to add to that as we did. So right now the airmass coming into the eastern part of the Metro area is cold enough to produce snow or freezing rain. Those areas a few degrees above freezing will cool TO freezing as soon as the precipitation starts. Since the warming southerly wind has to overcome the evaporative cooling from that airmass, I think several inches of snow (2-3") are likely across most of the metro area, with 4"+ possible up in northern Clark county and the west end of the Gorge. This will happen between the start of precip. and 10pm.
For those of you hoping to get out of work or school tomorrow? That's unlikely since the temp warms dramatically during the night. The bulk of the lowlands should be up to at least 45 by sunrise with a gusty southerly wind blowing.
Now, I can't watch weather the rest of the afternoon, I have flooring to nail down. Life must go on…Mark Nelsen