AccuWeather meteorologists say that an active pattern is ramping up across the Western U.S. this week that can pull in brisk, Arctic air and promote areas of heavy mountain snow. In the upper levels of the atmosphere, the jet stream will begin to plunge southward during the first half of the week, which will help usher in a large storm to the Northwest.
To start the week, conditions across the West can be somewhat mild for many locations compared to what will arrive by midweek. However, temperatures can stray between 3-6 degrees Fahrenheit below the historical average in many Northwest towns and cities on Monday, including Eugene, Oregon, Billings, Montana and Seattle.
