Blizzard conditions develop as a mesoscale band of heavy snow develops along a surface boundary emerging off of The Rocky Mountain Front. Temperatures drop into the single digits behind the boundary, while wind gusts exceed 45 mph at many locations. Mesoscale models place this band of snow right along the eastern edge of The Rocky Mountain Front, but it forms and becomes nearly stationary along, or just west of I-15. Snowfall rates within this band are expected near two inches per hour, resulting in 6 to 9 inches of new snow in just a few hours. Although not quite in the right location, most of the high resolution model guidance weakens this boundary late in the evening. The large scale upper level low responsible for this event becomes stationary over southwest Oregon. Embedded shortwave features continue to rotate over the region and producing nearly continuous, widespread snow through Thursday. Snowfall intensity decreases as the localized snowband weakens, but snow becomes generally more widespread. Snow-water ratios remain high, meaning this is a powder snow that will blow easily and cause reduced visibility and drifting problems across many roads with light to moderate winds. Winds increase across the region as the surface low tracks through southern Idaho on Thursday. Snowfall dissipates on Thursday night with shortwave ridging aloft.

Winter Weather in SOUTHERN LEWIS AND CLARK, MONTANA
From 27-NOV-19 13:15:00 to 27-NOV-19 13:15:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

New snowfall of 7 inches over Augusta, MT. Relayed through ham radio operator.

Winter Weather in CASCADE, MONTANA
From 27-NOV-19 15:05:00 to 27-NOV-19 15:05:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter reports drifts forming on mt-200 between Sun River and Simms. Winds of 20 to 35 mph. Visibility reduced to 100 feet at times.

Blizzard in EASTERN TETON, MONTANA
From 27-NOV-19 18:00:00 to 27-NOV-19 18:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

New snow of 14 inches reported in the past 24 hours. 35 to 40 mph winds all day. 1 NW Choteau.

Winter Storm in EASTERN TETON, MONTANA
From 28-NOV-19 06:30:00 to 28-NOV-19 06:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

COOP observer station bynm8, Bynum 4 SSE. Two day total.

Winter Storm in EASTERN TETON, MONTANA
From 28-NOV-19 07:00:00 to 28-NOV-19 07:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

CoCoRaHS station mt-tn-3. 3 ENE Dutton. Air temp 8 F at obs time.

Winter Storm in TOOLE, MONTANA
From 28-NOV-19 09:00:00 to 28-NOV-19 09:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

COOP station slbm8, shelby. Two-day total, with snowfall estimated due to severe blowing and drifting. Air temp 12 F at time of ob.

Winter Storm in CASCADE, MONTANA
From 28-NOV-19 11:00:00 to 28-NOV-19 11:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

Storm total at NWS Great Falls office as of Thursday 18Z.

Winter Storm in CASCADE, MONTANA
From 28-NOV-19 08:00:00 to 28-NOV-19 08:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

New snowfall of 10 inches measured 13 miles SSE Ulm.

Winter Storm in EASTERN GLACIER, MONTANA
From 28-NOV-19 14:40:00 to 28-NOV-19 14:40:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: CoCoRaHS

Snow total estimated due to drifiting. New snowfall estimated at 14 inches. Drifts in town of 3 to 5 feet.