A WINTER STORM WARNING is in effect until Friday.  Snow will spread across the state tonight, with several inches accumulating by morning.  Snow in the morning will gradually taper off by afternoon.  Highs will be in the 0s and 10s.

Another round of snow will hit Montana Thursday night into Friday, as another surge of arctic air moves into the state.  Temperatures will drop through the day on Friday, falling below 0.  Northwest winds up to 20mph will create dangerously cold wind chill values down to -30.  Light snow will fly, with an additional light accumulation.  Friday night, arctic high pressure will move directly over the state.

With clearing skies, and a healthy amount of snow on the ground, temperatures will drop to between -20 and -40 across the state.  It will be the coldest night in years, with near record low temperatures.  Saturday, skies will be mostly sunny but temperatures will remain near 0.  By Saturday afternoon, west winds will begin to pick up along the Rocky Mountain Front and the Hi-Line.

Blowing snow is likely, and dangerously cold wind chills will develop.  This is the beginning of a “chinook”, and temperatures will steadily warm through early next week.

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However, blowing and drifting snow will be very problematic, and wind chill values will remain very cold.  From Friday night’s lows to Tuesday’s highs, parts of Montana will experience a 70 degree temperature swing!

And if you’re looking ahead to Christmas, I’m watching a new storm that could move in on Christmas Eve.  Most of Montana should have a white Christmas with the snow already on the ground, and more snow likely.

Be careful with the snow and the dangerously cold temperatures.

Curtis Grevenitz

Chief Meteorologist