Mild for a few days, and then frigid air settles in

Posted at 6:08 PM, Dec 21, 2021
and last updated 2021-12-22 10:37:20-05

Tuesday night: High pressure will continue to weaken as a trough begins to dig into the Rockies throughout the night. This will keep us on the breezier side throughout the night. Wind gusts up to 40mph still possible. Even higher gusts up to 60mph possible for the Rocky Mountain Front. Temperatures will bottom out in the low to mid 30s.

Wednesday: Seasonably mild and breezy. Wind gusts up to 40mph possible, 60mph+ for the Rocky Mountain Front. Mostly sunny to partly cloudy skies. Temperatures will climb into the mid 40s. Partly cloudy skies continue overnight as temperatures fall into the upper 20s.

Thursday: Mild and a bit breezy with wind gusts up to 35mph possible. Mostly sunny skies. High temperatures in the low to mid 40s. A couple of snow showers are possible at night as an arctic cold front passes through later in the night. The winds will briefly pick up as the front passes through. Overnight lows in the low to mid teens.

Christmas Eve: Temperatures start out in the low to mid 20s but will fall during the afternoon and evening. Mid to upper teens by dinnertime. Otherwise, a few flurries or light snow showers are possible, especially in the mountains. Temperatures will fall to either side of 0 degrees across the area. Wind chills as low as -15 degrees possible.

Christmas Day: The early morning hours will feature dangerous wind chills as low as -15 degrees. Temperatures will start out below zero for most of north central Montana, with single digits for the rest of central Montana. Temperatures climb to the low to mid teens with a few snow showers possible, especially for Helena. Temperatures fall quickly to dangerous levels Christmas night. Lows will be -10 to -20 degrees with wind chills as low as -30 for the Hi-Line.

Frigid start to Christmas.

Sunday: Mostly sunny to partly cloudy skies and a few, spotty snow showers. High temperatures just above zero, with subzero highs for the Hi-Line. Overnight temperatures fall to -15 to -20 degrees for most areas, slightly warmer lows for the Helena area.

Monday: Dangerously cold with many areas struggling to reach 0 degrees. Subzero wind chills throughout the entire day. Partly to mostly cloudy skies expected. Extremely dangerous overnight lows falling to -20 to -30 degrees. Frostbite can develop on exposed skin in 15-20 minutes in these kind of temperatures.

Dangerous overnight low temperatures leading up to the new year.

Tuesday: Subzero high temperatures, slightly warmer for the Helena area. Scattered snow showers are possible for the Rockies and Helena area. Otherwise, partly cloudy skies expected.