The first winter storm of the season is bearing down on the Pacific Northwest and Northern Rockies, where some mountain locations probably will receive 1 to 2 feet of snow late Tuesday through early Friday. Forecasters are warning of multiple waves of heavy snow and dangerous road conditions from Montana to North Dakota along with temperatures that are expected to drop to the single digits in some places.
“A long duration winter storm will begin today across the Pacific Northwest and Northern Rockies, and continue through the end of the week through portions of the Northern Plains,” the National Weather Service said Tuesday. “Bands of heavy snow … will likely result in difficult travel due to snow covered or icy roads, and poor visibility.”
Winter storm warnings and watches have been posted across a region stretching from Washington state eastward to North Dakota, including such major populations centers as Great Falls, Mont.; Billings, Mont.; and Bismarck, N.D. Snowfall rates near or over 1 inch per hour have at least a 70 percent chance of producing more than 8 inches of snow, and a 10 to 30 percent chance of producing localized amounts of 18 inches, the Weather Service said.
Difficult driving conditions and delays are expected across mountain passes, with a foot or more of snow possible in the Cascades and portions of the Absarokas and Crazy Mountains.
Another surge of chilly air is forecast to arrive in the Northern Plains this weekend and could dive as far south as Texas by Halloween.
Montana forecast
The storm is expected to come in two waves in Montana. The first round will start as a mix of rain and snow Tuesday afternoon in western and central Montana before changing to all snow Tuesday night as temperatures drop below freezing. The second round of snow looks to focus on central and eastern Montana on Thursday into Thursday night, dropping temperatures into the teens and 20s during the day and into the single digits at night.
For those areas under a winter storm warning Tuesday evening into Wednesday evening, a span including much of central and western Montana, “Travel could be very difficult to impossible and tire chains may be required for some vehicles. Areas of blowing snow could significantly reduce visibility. Those in the backcountry should ensure they are prepared for dangerous conditions,” the Weather Service said. “The hazardous conditions could impact the Tuesday evening and Wednesday morning commutes.”
Snow accumulation forecasts
- Great Falls: 8-12 inches
- Helena: 12-18 inches
- Bozeman: 8-12 inches
- Billings: 6-8 inches
North Dakota forecast
Much of northwestern North Dakota has the potential for at least 8 inches of snow late Tuesday night through late Thursday night. The snow is expected to start in the northwest and north-central portions of the state Wednesday through Wednesday night, then spread south and east Thursday through Thursday night. The highest accumulations are forecast for the portion of the state north and west of Bismarck.
A winter storm watch is in effect late Tuesday night through late Thursday night for the northwest half of the state, where the Weather Service predicts a 70 to 90 percent chance of at least 6 inches of snow. “Travel could be very difficult. The hazardous conditions could impact the morning and evening commutes Wednesday and Thursday,” the Weather Service said.
Snow accumulation forecasts
- Bismarck: 3-7 inches
- Washburn: 6-10 inches
- Minot: 9-16 inches
- Dickinson: 6-11 inches
- Williston: 10-17 inches
Washington state and Oregon forecast
Heavy snow is likely in the Cascades and Olympics on Tuesday through Wednesday afternoon. Snow levels could drop as low as about 2,000 feet in the Cascades. At lower elevations, including Seattle and along the state’s Pacific coast, precipitation will take the form of a chilly rain, with 1 to 2 inches in some places through late Wednesday.
For those areas under a winter storm warning in northern Washington, especially at elevations above 3,000 feet, “travel could be challenging and difficult over mountain passes and high elevation roadways. These winter weather conditions will impact the Tuesday evening and Wednesday morning commutes on higher elevation roadways and passes,” the Weather Service said. “Low elevation locations and roadways may see seasonal conditions and caution should be taken.”
Snow accumulation forecasts
- Above 3,000 feet: 8-16 inches
- Above 5,000 feet: 16-30 inches
Halloween cold blast from Northern Plains to Texas
While above normal temperatures will continue through the upcoming weekend, models are beginning to converge on the arrival of a strong cold front on the 30th or 31st. Halloween will likely be chilly, and potentially wet, but stay tuned later this week for more details! pic.twitter.com/vt95xJAW5i
— NWS Austin/San Antonio (@NWSSanAntonio) October 23, 2023
Forecast models are signaling another surge of very cold air next weekend into early next week, just in time for Halloween. Arctic air is forecast to surge south from Canada into the Northern Plains, with freezing overnight conditions potentially as far south as Oklahoma and Central Texas.
The unseasonably cold air not only could make for chilly trick-or-treating, but it also threatens to damage crops.
“Agricultural impacts include potential damage to emerging winter wheat in Montana. However, any protective snow cover may lower the damage risk. The rapid transition to colder temperatures could stress livestock across the northern Great Plains, and [cause] damage to un-winterized water systems such as sprinkler systems,” the Weather Service said.
