FastCast—Monday, Nov. 28 to Tuesday, Nov. 29:
After a stormy and active weekend, another system will bring a localized chance of lowland snow on Monday morning. The best chance of lowland snow will be from Everett northward, with a lesser chance in the Cascade foothills. Snow could occur with any precipitation in these favored locations throughout the day, but is most likely on Monday morning. For areas from Everett northward, 1-4 inches of snow are possible. For areas in the foothills, a dusting to 2 inches of snow are possible. For areas that don’t receive snow, 0.1-0.25 inches of rain are possible. Expect highs in the mid 30s to near 40, and lows in the mid to upper 20s. Biting north winds will bring gusts of 20-25 mph around the Sound, and 40-55 mph in Whatcom County. Wind chills will range from the mid 20s to low 30s in the lowlands to the low teens to low 20s in Whatcom County. In the Cascades, expect another 1-2 feet of snow through Tuesday. Mountain pass travel will be difficult. Wind chills in the mountains will be in the single digits to mid teens. Another chance of lowland snow is possible on Tuesday, and again on Wednesday, so stay tuned for more information in the next blog post.
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Continue reading the full blog below!
After an active weekend, cold air has entered the lowlands, bringing multiple marginal chances of lowland snow throughout the week. We will examine each chance with a preceding blog post, so that we can have the most accuracy per forecast. So, let’s start with Monday’s snow chance.
The best chance for accumulating snow will be from very late Sunday night to midmorning on Monday.
Below is the UW model, the highest-resolution snow model available in the Pacific Northwest. This is showing snow through 12 AM Tuesday.
The UW model shows the best chance of accumulating snow from Everett to Bellingham. This forecast shows a total of 0.5-4 inches in these areas. A lesser chance of lowland snow is possible for the foothills, with 0.25-2 inches possible.
Another forecast is available from the high-resolution HRRR model, showing snow through 11 PM Monday.
The HRRR shows a different scenario, with 1-3 inches in the foothills and a dusting to 0.5 inch from Everett south to Olympia. This scenario is less likely.
Finally, the we’ll look at the NAM high-resolution forecast, also through 11 PM Monday.
The NAM forecast generally agrees with the UW forecast, showing a localized band of a dusting to 3 inches of snow in northern Snohomish and southern Skagit Counties, and a dusting to 1 inch in the foothills.
Overall, the best chance of snow on Monday morning is from Everett northward to the Canadian border. A lesser chance exists in the Cascade foothills, and a slight chance exists from Everett southward through the metro area.
Also on Monday, Fraser Gap outflow winds will strengthen across Whatcom and San Juan Counties. The main impacts of the winds will be isolated tree damage and power outages and cold wind chills. Expect gusts of 40-50 mph in Whatcom and San Juan Counties, and 20-25 mph around the rest of the region, strongest near the water. Below is the HRRR forecast for wind chills at 3 PM Monday.
By Monday afternoon, lowland wind chills will be in the mid to upper 20s. Whatcom and San Juan Counties will have wind chills in the low teens to low 20s all day, and Eastern Washington will also have wind chills in the low teens to upper 20s all day. At the passes and mountain communities, wind chills will be in the single digits to upper teens. Winds will decrease on Tuesday, but chilly conditions will still remain.
This week will be a “now-cast” scenario, with the best forecasts within hours of the upcoming weather. To stay updated, stay tuned to the blog and Twitter (accessed on the top right of the blog).
Be prepared for winter conditions, especially in the mountains. Stay safe and stay warm!
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