A taste of winter weather arrives in the Northwest this week
A pattern change occurring in the northwestern United States this week will spread the potential for early season snow, especially across mountain ranges. For some locations, forecasters say this week’s pattern will bring the first snowflakes since last winter.
“A cold storm system descending from western Canada will bring chances for snow accumulation at the highest elevations in the Northwest through the middle of this week,” AccuWeather Senior Meteorologist Heather Zehr explained.
AccuWeather meteorologists say the best chances for snow will be across the higher terrain of the Cascades, northern areas of the Sierra Nevada mountain range and some of the highest elevations in the northern Rockies. The cold air mass seeping south from Canada is expected to lead to a gradual drop in temperatures until mid-week.
“Early Tuesday night, a low pressure area is expected to drop into western Washington, and conditions will become cold enough for snow to begin falling in northern Cascade, with snow levels falling below 6,000 feet. The risk of snow will increase after that,” Zehr said. Snow will rise south and east into Oregon on Wednesday although snow levels will be slightly higher.
By Wednesday, cities in Washington, such as Seattle and Spokane, are expected to dip to average temperatures below 60 degrees Fahrenheit for daytime highs. Nighttime temperatures in Seattle are not expected to differ much from the lows in the 50s observed at times throughout September. However, conditions in Spokane this week could drop into the 40s overnight, a value that has so far only been observed once earlier this month.
There will be a dramatic difference in temperature values at the end of the weekend compared to the highs expected later this week. Many cities, such as Portland, Oregon, and Reno, Nevada, will see daytime temperatures 20 to 25 degrees Fahrenheit lower than their weekend values.
“A cold core will mainly grip areas of Washington and Oregon around midweek, and freezing levels are expected to drop to about 7,000 or 8,000 feet in some locations during daylight hours,” AccuWeather Senior Meteorologist Adam Doty explained.
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Parts of the Elkhorn Mountains and Eagle Caps in the heart of the Wallowa Mountains could get light snow accumulations by Tuesday night. Mountain peaks like Sacajawea Peak in the Wallowa Mountains of northeastern Oregon and Burra Peak in central Idaho will be among some of the mountain peaks at risk of seeing chips around midweek, as they both rise to 9,843 feet and 12,662 feet, respectively.
This week’s pattern may spark excitement for avid skiers eagerly awaiting the opening of mountain resorts this fall. Typically, ski resorts across the Rockies and Cascades open sometime between late October and November, depending on seasonal conditions and location.
For snow lovers in general, the early season shift to cooler conditions and the potential for accumulating snowfall could be exciting for many in the West hoping to catch a glimpse of a few flakes.
“The most likely time and place for snow to fall is central and eastern Oregon on Thursday with snow levels falling below 6,000 feet again, but snow could fall south to the highest peaks of the northern Sierra with snow levels there dropping to 7,000-7,000 feet.” Zehr pointed to 9,000 feet.
Zahr added that with these snow levels, snow accumulation is expected to be above trail level during most days of the week although a few flakes may reach the trails. Travelers are advised to stay informed of the latest forecasts and monitor road conditions throughout the week, especially those planning a route through mountain passes.
By Friday, the storm is expected to move east across Nevada, and conditions will gradually become warmer. Most locations throughout the Northwest will see temperatures return to typical values for mid-to-late September.
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