The seasonal weather pattern continued to steer most precipitation away from the northeast corner and the eastern edge of Montana through the month. For some locations, severe drought conditions retreated slightly eastward (Daniels and northern Valley Counties).
Every event with a place to put it; 5 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS GGW wrote it up.
The seasonal weather pattern continued to steer most precipitation away from the northeast corner and the eastern edge of Montana through the month. For some locations, severe drought conditions retreated slightly eastward (Daniels and northern Valley Counties). For other locations, severe drought conditions expanded slightly southward (Richland County).
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Glasgow, MT wrote its last area forecast discussion before the first event at Nov 30, 2:45 PM MST, 9 hours 15 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 245 PM MST Mon Nov 30 2020 .DISCUSSION... 3pm discussion: Upper trof moving across the northern Rockies this afternoon with warm front lifting into eastern Montana. The cold front will follow with the upper low overnight, with a slight chance of light precipitation as it moves east. Freezing rain is possible across the south but should quickly change to snow. Strong cold air advection and subsidence behind the front will mix down some of the 30 to 60kt winds aloft for windy conditions on Tuesday. Some wrap around instability snow showers are also possible across the east on Tuesday evening. 9am update: No update this morning. Clear skies and warming temperatures expected today ahead of the upper trof. Current forecast looks on track. 3am discussion: Upper ridge will move through Eastern Montana today with warm temperatures and mostly clear skies. The ridge moves to the east this evening and an upper trough/low moves into the region tonight with a cold front. There will be enough moisture with this system late tonight and Tuesday for a chance of light snow/light rain/light freezing rain depending on temperatures. Gusty NW wind will develop behind the front during the day on Tuesday. An upper low drifts south along the MT/Dakota border Tuesday Night which will give the east a chance of light snow. Surface high on Wednesday will bring dry and cool weather to the area with clearing skies. An upper ridge and upper level high moves into the region on Thursday and becomes the dominate pattern through the weekend with warm and dry weather. && .AVIATION... VFR conditions are expected for most of the TAF period. A cold front will move across the region tonight with increasing cloud cover. A little mixed precipitation or snow is possible during the early morning hours, and could result in a brief period of MVFR conditions. Northwest winds will increase behind the front on Tuesday. Low level wind shear is a possibility at the terminals until the frontal passage early Tuesday morning. && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && weather.gov/glasgow
The national radar mosaic for the moment the first event began.
5 drought. Local standard time, as filed.
Drought conditions (D2-Severe) persisted across all of Sheridan County through the entire month of December.
Drought conditions (D2-Severe) persisted across all of eastern Roosevelt County through the entire month of December.
Drought conditions (D2-Severe) persisted over portions of western Roosevelt County - mainly east of MT Highway 13 and north of US Highway 2, through the entire month of December.
Drought conditions (D2-Severe) persisted over east-central and northeastern portions of Richland County through the month. Over the remainder of the eastern edge of the county, generally near and east of MT Highway 16, drought conditions (D2-Severe) began in the second week of the month and lasted through the remainder of the month.
Drought conditions (D2-Severe) persisted across central and eastern portions of Daniels County (generally near and east of MT Highway 13) through the entire month of December.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2020Every state in 2020This day in weather historyWarnings in Montana, December 2020
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 930336, 930338, 930339, 930344, 930357.