Under the Weather: First taste of winter to arrive this weekend with early-season cold snap

I don’t know about all of you, but scenes like the picture above just make me so happy to look at. I’m excited for winter. While we still have a couple months before winter officially arrives, we’re about to get the first real taste of it this weekend.

Unfortunately (or fortunately, depending on who you are), we’re only contending with cold temperatures, not lowland snow. Earlier this week, some models were suggesting the chance for a few flakes to fall in some lowland areas, but the latest runs have mostly backed off on that possibility for southwest Snohomish County.

So how cold is it supposed to get? Look at the temperatures shown with the GFS Ensemble below (at Paine Field). Most of the ensemble members show temperatures not even breaking out of the 40s for the next few days…talk about Octo-BRR. We could even see temperatures below freezing Sunday morning.

This possible first freeze is occurring a little earlier than usual. Using data from Paine Field since 1999, the average first freeze occurs in mid-November. In that same time frame, the earliest first freeze occurred on Oct. 29—so we have the chance to beat that.

Although we won’t have to deal with snow in the lowlands, the mountains are a different story, especially the northern Cascades. The highest resolution UW-WRF model (shown below) shows some areas exceeding 10 inches of newly accumulated snow through Saturday night. That’ll make skiers and snowboarders happy. This also means that travel through the mountains, especially Stevens Pass, might be a little bit difficult. If you have pass travel planned, make sure to take the necessary precautions.

Most of our weekend will be marked by the cold, but we also have to contend with some rain, primarily on Friday. We could see between 0.25 and 0.50 inches of rain before drying out and really cooling down. Notice how we’re expected to clear out Saturday night (in the image below). This will open the door for temperatures to really plummet. At night, clouds act like a blanket, trapping heat in Earth’s atmosphere, thus keeping us warmer. Without that cloud blanket, that heat is able to escape more effectively, cooling us down more.

After the rain on Friday, it is shaping up to be a beautiful weekend to head to the pumpkin patches and corn mazes—just make sure to bundle up!

— By Kelsie Knowles

Kelsie Knowles is a meteorologist and recent University of Washington graduate who lives in north Lynnwood. After writing weather blogs as a KOMO News intern, she discovered a passion for writing about weather. You can learn more in her blog www.wxnoggin.com and you can also follow her on Twitter at @kels_wx3.

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