Most of January has been mild in regards to temperature and snow, but the final weekend and last several days of the month have harsh winter weather return with severe cold and significant snow. Several inches will accumulate, while temperatures drop below 0, and wind chills may drop down to the -20 to -40 range. This upcoming arctic outbreak will be dangerous and harsh but likely will not be as intense as the record breaking cold and snow that hit Montana before Christmas.
The serious cold and snow are still a few days away but the weather will be anything but dull until then. An active northwest flow will continue to deliver clouds, snow and strong wind to parts of the state. A wave of low pressure will bring areas of light snow on Wednesday, mainly in and near the mountains. Some light snow is likely across the plains through the day as well. Highs will not be cold yet with readings topping out in the 30s to near 40. Wind will gust as high as 30-40mph on the Continental Divide and out across the plains. Snow may accumulate 1-2" in the lower elevations with up to 4" in the mountains. Thursday will be somewhat similar with areas of snow and wind. However, warm enough air will move in that some rain may fall in the lower elevations especially across north-central Montana with highs reaching the 40s there. Most of the state will warm into the 30s and 40s with 20s in the mountains. A light accumulation of 1-3" will fall in the mountains. The valleys and plains should mainly be wet with the mix of rain and snow or just plain light rain. Wind will be very strong on the Divide and across the plains with gusts topping 40-50mph in some places. Friday is when the weather really starts to go downhill. Widespread moderate to heavy snow will develop for most of the state. Highs will be in the upper 20s to the mid 30s. Several inches will fall through the day with the snow continuing into the night. The arctic airmass will slowly spill into the state from northeast to southwest through Friday night into Saturday. Saturday will be much colder with areas of lighter snow tapering off later in the day. Total snow accumulation will likely range from 3-8" in the lower elevations with 8-16" in the mountains. Highs will likely top out in the 0s and 10s. That's not terribly cold but it will continue to get colder through Saturday night into Sunday. Sunday will be very cold with highs in the -0s and 0s. There will be some sun as well as some light snow showers. Overnight lows will drop down to between -10 and -20. Very cold air with highs near 0 and lows well below 0 will continue for most of next week. This looks like a prolonged stretch of harsh winter weather.