A potent upper level closed low and associated trough began to dig southeast along the British Columbia Coast during the morning hours of Friday, September 27th, 2019, reaching over Vancouver Island during the evening hours on Friday.  By Saturday (September 28, 2019) morning the trough had dug substantially along the Pacific Coast of the United States, with the broad closed low positioned over the western two-thirds of the state of Washington and northern third of Oregon. As the day progressed on Saturday the trough dug even further south into Southern California and began to take on a neutral tilt, all the while the closed low slowly meandered to over the Oregon and Washington borders. This neutrally tilted trough would then persist over the western third of the United States through Sunday (September 29, 2019) evening, with the closed low remaining nearly stationary over the Columbia River Valley of Oregon and Washington over this time frame. This upper level pattern from Friday through Monday (September 30, 2019) allowed for abundant Pacific moisture to be transported east and northeast over the Northern Rockies, which combined with strong easterly and northeasterly upslope flow in the low-to-mid levels and cold air filtering south from Arctic, allowed for widespread snow to develop over North Central and portions of Southwest Montana.

Winter Storm in SOUTHERN LEWIS AND CLARK, MONTANA
From 28-SEP-19 09:15:00 to 28-SEP-19 09:15:00 (MST-7)
Reported by: Department of Highways

MDT reports severe driving conditions on Montana highway 200 from Rogers Pass to the highway 434 Junction.

Winter Storm in SOUTHERN ROCKY MOUNTAIN FRONT, MONTANA
From 28-SEP-19 11:05:00 to 28-SEP-19 11:05:00 (MST-7)
Reported by: Utility Company

The City of Choteau Public Works Director requested that people stay off the roads due to fallen trees and power lines.

Winter Storm in NORTH ROCKY MOUNTAIN FRONT, MONTANA
From 28-SEP-19 13:00:00 to 28-SEP-19 13:00:00 (MST-7)
Reported by: Tribal Official

Browning Water Plant went down, which impacted the residents of Browning and East Glacier. The plant was back in operation later that afternoon. Message relayed by Facebook.

Blizzard in SOUTHERN ROCKY MOUNTAIN FRONT, MONTANA
From 29-SEP-19 12:00:00 to 29-SEP-19 12:00:00 (MST-7)
Reported by: Department of Highways

Extreme driving conditions reported along Montana Highway 287 from Choteau to Bowman���s Corner, and Montana Highway 21 from Simms to Augusta.

Blizzard in NORTH ROCKY MOUNTAIN FRONT, MONTANA
From 29-SEP-19 13:20:00 to 29-SEP-19 13:20:00 (MST-7)
Reported by: Tribal Official

The Blackfeet Nation Tribal council reports that all roads in and out of the Blackfeet Nation Reservation have been closed or are experiencing severe driving conditions.

Heavy Snow in CASCADE, MONTANA
From 29-SEP-19 17:00:00 to 29-SEP-19 17:00:00 (MST-7)
Reported by: Official NWS Observations

NWS Great Falls (5 WSW Great Falls) reported 19.3 inches for a storm total.

Heavy Snow in SOUTHERN ROCKY MOUNTAIN FRONT, MONTANA
From 29-SEP-19 18:15:00 to 29-SEP-19 18:15:00 (MST-7)
Reported by: Broadcast Media

KRTV reported a storm total of 18 inches in Dutton.

Heavy Snow in SOUTHERN ROCKY MOUNTAIN FRONT, MONTANA
From 29-SEP-19 19:30:00 to 29-SEP-19 19:30:00 (MST-7)
Reported by: SNOTEL

Dupuyer Creek SNOTEL (14 SW Dupuyer) reported a 48 hour storm total of 48 inches.

Heavy Snow in SOUTHERN LEWIS AND CLARK, MONTANA
From 29-SEP-19 17:00:00 to 29-SEP-19 17:00:00 (MST-7)
Reported by: Park/Forest Service

The Rocky Mountain Ranger Station (15 SW Augusta) reported a storm total of 25 inches, with snow drifts up to 3 to 4 feet.

Heavy Snow in JUDITH BASIN, MONTANA
From 29-SEP-19 13:31:00 to 29-SEP-19 13:31:00 (MST-7)
Reported by: Trained Spotter

A trained spotter at 4 W Utica reports 9 inches of snow since around 6AM on Saturday the 28th. Liquid equivalent total was 1.16 inches.

Heavy Snow in FERGUS, MONTANA
From 29-SEP-19 12:30:00 to 29-SEP-19 12:30:00 (MST-7)
Reported by: Trained Spotter

A trained spotter at 2 SE Lewistown (elevation 4200 ft) reported 9 inches of snow accumulation since 6AM September 28th.

Heavy Snow in BLAINE, MONTANA
From 29-SEP-19 06:45:00 to 29-SEP-19 06:45:00 (MST-7)
Reported by: Trained Spotter

A trained spotter at 13 E Lloyd reported 14 inches of snow.

Heavy Snow in HILL, MONTANA
From 29-SEP-19 14:30:00 to 29-SEP-19 14:30:00 (MST-7)
Reported by: Public

Public reported 12.5 inches of snow at 1 NNE Havre.

Heavy Snow in NORTH ROCKY MOUNTAIN FRONT, MONTANA
From 29-SEP-19 19:30:00 to 29-SEP-19 19:30:00 (MST-7)
Reported by: SNOTEL

The Badger Pass SNOTEL site reported an estimated snow accumulation of 34 inches.

Heavy Snow in SOUTHERN ROCKY MOUNTAIN FRONT, MONTANA
From 30-SEP-19 07:00:00 to 30-SEP-19 07:00:00 (MST-7)
Reported by: Trained Spotter

A trained spotter at 17 WSW Bynum reported a storm total of 46 inches, with estimated 7 foot drifts.

Heavy Snow in EASTERN GLACIER, MONTANA
From 30-SEP-19 07:00:00 to 30-SEP-19 07:00:00 (MST-7)
Reported by: Public

Public reported 22 inches of snow accumulation at Cut Bank, measurements were averaged over 10 locations. Hvy Snow E.Glacier.

Blizzard in NORTH ROCKY MOUNTAIN FRONT, MONTANA
From 30-SEP-19 15:30:00 to 30-SEP-19 15:30:00 (MST-7)
Reported by: Tribal Official

BlackFeet Nation Emergency Management reported a storm total of 48 inches, widespread whiteout conditions were being observed at the time of the report.

Winter Storm in SOUTHERN ROCKY MOUNTAIN FRONT, MONTANA
From 28-SEP-19 06:00:00 to 28-SEP-19 06:00:00 (MST-7)
Reported by: Utility Company

Northwest Energy reports 462 customers without power in Choteau due to heavy snow falling on trees and power lines.

Blizzard in EASTERN GLACIER, MONTANA
From 29-SEP-19 13:20:00 to 29-SEP-19 13:20:00 (MST-7)
Reported by: Tribal Official

The Blackfeet Nation Tribal council reports that all roads in and out of the Blackfeet Nation Reservation have been closed or are experiencing severe driving conditions.