WEATHER ALERT DAY: A winter storm will bring a round of moderate to heavy snowfall across western Montana beginning late tonight, lasting through Saturday. This will impact travel, especially late Friday into Saturday. As the snow begins to move out heading into Sunday, Arctic air really begins to settle in- bringing dangerous cold to western Montana through at least Tuesday morning...
For the rest of today, snow showers will slowly continue to spread across mainly the mountains and some of our mountain passes.
Late tomorrow overnight and into Friday, mountains/mountain passes will start to quickly see roads begin to become snow covered and slick travel is expected. Conditions will continue to deteriorate for the mountains Friday during the day as snow showers ramp up, although some valleys could see a rain/snow mix at times.
A period of time that is of particular concern is from Friday evening, overnight, and into Saturday morning. Late Friday overnight and into Saturday, the Arctic cold front will move across the divide. This will enhance snowfall rates, and will be accompanied by gusty NE winds around 30-40 MPH. Not only will a flash freeze on the roads be possible, but heavy snowfall and gusty winds will combine for areas of poor visibility. Blowing snow will also be a distinct possibility during this time period. Snow showers will generally come to a close on Saturday PM, with a few snow showers lingering into Sunday morning for southwest Montana. All in all, many valley locations will be in the 5-10" range for accumulations with mountains seeing up to a foot or two. For a full breakdown of forecast snow totals, be sure to view the Winter Storm Warnings that are in place for most of our region below. Bottom line: Significant travel impacts due to snow, cold, and wind can be expected Friday PM through Saturday AM.
High temperatures Sunday and Monday will be very cold, only reaching the single digits. Overnight lows will drop below zero Sunday through Wednesday morning. The coldest lows will likely occur Monday morning. Temperatures Monday morning will be in the 10s and 20s BELOW zero, or perhaps even colder for locations such as Butte. Wind chill values will be some 20 to 35 degrees below zero, if not colder, along the divide.
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WINTER WEATHER ADVISORY for the West Glacier Region and the Potomac/Seeley Lake Region through 5AM Friday. For the Winter Weather Advisory, snow expected. Total snow accumulations of 3 to 9 inches.
WINTER STORM WARNING for the West Glacier Region and the Potomac/Seeley Lake Region from 5 AM Friday through 11AM Saturday. For the Winter Storm Warning, heavy snow expected. Total snow accumulations of 9 to 17 inches. Winds gusting as high as 35 mph. Rapidly dropping temperatures could cause a flash freeze on area roadways late Friday afternoon and evening.
WINTER WEATHER ADVISORY for the Bitterroot/Sapphire Mountains through 5AM Friday. For the Winter Weather Advisory, snow expected. Total snow accumulations of 4 to 6 inches.
WINTER STORM WARNING for the Bitterroot/Sapphire Mountains from 5AM Friday through 1PM Saturday. For the Winter Storm Warning, heavy snow expected. Total snow accumulations of 12 to 20 inches.
WINTER STORM WARNING for the Northern Clearwater Mountains, Southern Clearwater Mountains, and the Lower Clark Fork Region. Heavy snow expected. Total snow accumulations of 14 to 25 inches. The heaviest snowfall will occur early Friday morning through midday Friday and again Friday evening through early Saturday.
WINTER WEATHER ADVISORY for the Kootenai/Cabinet Region in effect from 10PM this evening through 1PM Friday. For the Winter Weather Advisory, snow expected. Total snow accumulations of 3 to 5 inches.
WINTER STORM WARNING for the Kootenai/Cabinet Region from 1PM Friday through 1PM Saturday. For the Winter Storm Warning, heavy snow expected. Total snow accumulations of 5 to 8 inches with cold wind chills and poor visibility.
WINTER WEATHER ADVISORY for the Flathead/Mission Valleys through 1 PM Friday. For the Winter Weather Advisory, mixed precipitation expected. Total snow accumulations of 2 to 4 inches and ice accumulations of a light glaze. Tonight through Friday morning will see periods of heavy snow in Big Fork and along the east side of Flathead Lake with 6-8 inches of snow accumulation.
WINTER STORM WARNING for the Flathead/Mission Valleys from 1PM Friday through 1PM Saturday. For the Winter Storm Warning, heavy snow expected. Total snow accumulations of 5 to 8 inches. Winds gusting as high as 35 mph. Rapidly dropping temperatures could cause a flash freeze on area roadways late Friday afternoon and evening. Blowing snow will cause reduced visibility and near blizzard conditions are possible.
WINTER STORM WARNING for the Missoula/Bitterroot Valleys from 1PM Friday through 1PM Saturday. Heavy snow expected. Total snow accumulations of 5 to 8 inches. Flash freeze possible on area roads during the Friday evening commute.
WINTER WEATHER ADVISORY for the Butte/Blackfoot Region through 1PM Friday. For the Winter Weather Advisory, snow expected. Total snow accumulations of 4 to 8 inches.
WINTER STORM WARNING for the Butte/Blackfoot Region from 1PM Friday through 1PM Saturday. For the Winter Storm Warning, heavy snow expected. Total snow accumulations of 7 to 12 inches. Rapidly dropping temperatures could cause a flash freeze on area roadways late Friday afternoon and evening.
WINTER STORM WARNING for the Upper Blackfoot and MacDonald Pass, Little Belt and Highwood Mountains, Snowy and Judith Mountains, Big Belt, Bridger and Castle Mountains, Elkhorn and Boulder Mountains, Northwest Beaverhead County from 5PM this afternoon through midnight Saturday night. Heavy snow expected. Total snow accumulations between 10 and 20 inches, with localized amounts approaching 30 inches. Winds gusting as high as 35 mph. Wind chill values as low as 30 degrees below zero on Saturday.
WINTER STORM WARNING for Meagher County Valleys, Madison River Valley, Gallatin Valley. Including the following locations: Norris, Bozeman, Jeffers, Cameron, Ennis, Martinsdale, Ringling, White Sulphur Springs, Gallatin Gateway, McAllister, and Checkerboard. Heavy snow expected. Total snow accumulations between 5 and 10 inches. Winds gusting as high as 40 mph. Wind chill values as low as 20 degrees below zero on Saturday.
WINTER STORM WARNING for the Gallatin and Madison County Mountains and Centennial Mountains. Including the following locations: Raynolds Pass, Targhee Pass, Big Sky, and West Yellowstone through 6 AM Sunday. Heavy snow expected. Total snow accumulations between 10 and 20 inches, with localized amounts approaching 30 inches. Winds gusting as high as 45 mph. Wind chill values as low as 30 degrees below zero on Saturday.
WINTER WEATHER ADVISORY in effect from 11AM Friday through midnight Saturday night for Helena Valley-Canyon Ferry Area-Missouri Headwaters-Beaverhead and Western Madison below 6000ft-Ruby Mountains and Southern Beaverhead Mountains. Including the following locations: Willow Creek, Waterloo, Whitehall, Helena, Glen, Winston, Three Forks, Pony, Toston, Townsend, Bannack, Dillon, Harrison, and Monida Pass. Snow expected. Total snow accumulations between 3 and 7 inches, with isolated amounts approaching 10 inches in the South Hills. Winds gusting as high as 35 mph. Wind chill values as low as 20 degrees below zero on Saturday.