WEATHER DISCUSSION: Snow showers gradually develop over north central Montana Sunday afternoon and evening. By Monday morning, a widespread 1-4 inches of accumulation is expected. Impacts diminish into eastern Montana. Some clearing is expected in central Montana on Monday, however steadier snow continues near the I-90 corridor.
A low pressure begins to strengthen as it pulls into the Dakotas Monday night into Tuesday. Bands of heavier snow begin to impact eastern Montana on Tuesday, with the heaviest snow expected Tuesday night into Wednesday. Upwards of a foot of snow is possible east of a line from Glasgow to Billings. Prepare for dangerous travel and potential road closures along I-90 and I-94 east of Billings through Thursday morning.
A pattern change impacting the entire Lower 48 arrives for the northern Rockies on Monday. Temperatures will consistently be below average through much of the rest of December. Temperatures will not be anything not already seen this winter in central Montana, with highs largely in the 10s and 20s and overnight lows in the -0s and 0s. Nonetheless, the cold is going to be persistent for at least a couple of weeks.
SATURDAY NIGHT: Mostly cloudy near the Continental Divide, with less cloud cover further east. Overnight lows in the low to mid 20s for central Montana, 0s and lower 10s for the Hi-Line.
SUNDAY: Snow showers developing throughout north central Montana. Highs in the mid to upper 30s for central Montana, low to mid 20s for the Hi-Line. Periods of snow continuing overnight as temperatures fall into the upper 0s and lower 10s.
MONDAY: Snow tapering, with scattered snow showers continuing. Mostly cloudy. Highs in the mid to upper 10s. Scattered snow showers continuing overnight, especially east of a line from Havre to Lewistown. Overnight lows in the 0s.
TUESDAY: Mostly sunny for the Rocky Mountain Front, with increasing cloud cover further east. Snow showers likely east of a line from Havre to Lewistown. Periods of heavy snow in far eastern Montana. Highs in the mid to upper 10s. Periods of heavy snow continuing overnight in eastern Montana. Elsewhere, mostly cloudy skies as temperatures fall into the 0s.
WEDNESDAY: Moderate to heavy snow in eastern Montana, with scattered snow showers throughout the rest of central Montana. Highs in the mid to upper 10s. Snow showers gradually taper overnight as temperatures fall into the 0s.
THURSDAY: Scattered snow showers in the morning, followed by increasing sunshine during the afternoon. Highs in the upper 10s and lower 20s. Mostly cloudy overnight as temperatures fall into the -0s and 0s.
FRIDAY: Mostly sunny. Highs in the 10s. Increasing clouds overnight as temperatures fall to -10 to 5 degrees.
SATURDAY: Mostly sunny with highs in the 10s for the Hi-Line, low to mid 20s for central Montana.