Cold air has generally been on the retreat across much of the United States so far this March, but a fresh wave of Arctic air is poised to slash temperatures by 50-80 degrees Fahrenheit from their midweek highs, and it will have snowy consequences by this weekend.
The interior Northwest and northern Rockies are notorious for dramatic temperature swings and although the upcoming setup will not break temperature plummet records, it should not disappoint extreme-weather enthusiasts.
Electric Peak, Yellowstone National Park, Montana.
The greatest temperature change in 12 hours for the U.S. was an 84-degree plummet at Fairfield, Montana, on Dec. 14, 1924. The temperature fell from 63 degrees above zero to 21 degrees below zero.
Temperatures are forecast to climb into the 40s, 50s and 60s during the middle of this week over the region.
However, as Arctic air blasts southward late this week and this weekend, temperatures will tumble and may struggle to get above zero over the higher terrain and may not get past the single digits and lower teens for high temperatures on Saturday.
"For many in the region, this will be a dose of January-like cold," AccuWeather Chief Broadcast Meteorologist Bernie Rayno said.
Nighttime lows are likely to be at or below zero over a broad area of western and central Montana to northwestern Wyoming Saturday night.
The cold air will even spread to the coastal areas of the Northwest thanks to winds that turn from the east and northeast.
The average high temperature in Seattle for the middle of March is in the middle 50s. During this weekend, high temperatures may be held to the lower 40s to perhaps the upper 30s, or 10-15 degrees below average.
Precipitation will accompany the Arctic blast.
Snow will fall over the northern Rockies, adjacent High Plains and Cascades as well as outside of the higher elevations.
The surging Arctic air will cause snow levels to lower to the valley floors east of the Cascades and may even dip to a few hundred feet along the Washington and northern Oregon coasts this weekend.
"It's possible some snow falls or at least snowflakes are seen around the Seattle area this weekend," Rayno stated.
"This may turn into a blizzard," Rayno said, referring to strong winds and snow accompanying the Arctic surge. Blizzard conditions could evolve over the passes and along the eastern slopes of the northern Rockies and Cascades.
Motorists who are expecting to travel this weekend should be prepared for midwinter conditions over the interior Northwest and northern Rockies. Conditions could get bad enough for some roads along the Interstate 15 and 90 corridors to close for a time due to safety issues.
The adverse weather conditions may affect Yellowstone National Park this weekend.
"There is the potential for 1-2 feet of snow to fall over the high country of the northern Rockies and Cascades," Rayno said. "Heavy snow will shift farther south into portions of the Sierra Nevada early next week."
An AccuWeather Local StormMax™ of 30 inches is forecast for portions of north-central Montana, Yellowstone National Park and part of the northern Sierra Nevada.
Heavy mountain snow may be welcomed in areas where drought conditions are increasing in Northern California as the dry season rapidly approaches.
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