Accumulating rain and snowfall from the night before provided ample surface moisture just before skies cleared during the evening. By early morning on the 27th, temperatures had dropped into the mid 20s and easily allowed for freezing fog to develop main near and north of US Highway 2.
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.
Accumulating rain and snowfall from the night before provided ample surface moisture just before skies cleared during the evening. By early morning on the 27th, temperatures had dropped into the mid 20s and easily allowed for freezing fog to develop main near and north of US Highway 2.
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 Mar 26, 7:18 PM MST, 5 hours 27 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 818 PM MDT Fri Mar 26 2021 .DISCUSSION... EVENING UPDATE: With rain and snow moving through the area. Have raised PoPs up to much higher numbers over the predicted area for the next 12 hours. Placement and timing of precip still looks to be on track, just more of it coming down than first anticipated. GAH AFTERNOON DISCUSSION: Forecast challenges include chances for scattered showers this afternoon through tonight; Temperatures and fire weather concerns on Sunday; and a sharp and distinct cold front on Monday afternoon and evening. Current scattered showers over northern Phillips County have actually be reported by a fire crew there as snow with an ambient temperature of 40 degrees. If it happens to mix with rain this afternoon, it should quickly change over to all snow later. Snow accumulations of trace up to half an inch are possible, especially near Opheim. Saturday through Sunday, high pressure builds into the region from the west and southwest, allowing temperatures to climb. By Sunday expect many locations to reach 70 degrees. It will also be a day of fire weather concerns. See fire weather discussion. Monday through Monday night, a strong cold front is lined up to push through the region. It will be a difficult temperature forecast for that day. If the front is quick, we may not see as warm of temperatures currently forecast. The associated precip riding the cold front will likely be all snow with some little accumulation. More details to come. Winds will also be a concern. Sustained winds in excess of 40 mph are possible. Wednesday and beyond, a more-stable high pressure ridge rebounds into the region and brings a longer period of warm weather, but will be void of any precipitation. && .AVIATION... FLIGHT CAT: VFR - MVFR WINDS: Light and variable tonight. W-NW winds 5-15 kts on Saturday. Becoming light and variable again Saturday evening. SYNOPSIS: VFR to possible MVFR ceilings overnight tonight. An upper level disturbance is dragging light rain transitioning to snow showers across northeast Montana TAF sites tonight. MVFR visibilities may be possible with any snow. Clearing skies are expected on Saturday with VFR ceilings. /GAH && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Sunday morning through Sunday evening for MTZ120-122-134>137. && weather.gov/glasgow
The national radar mosaic for the moment the first event began.
5 dense fog. Local standard time, as filed.
At the Poplar mesonet site (KPO1), visibility dropped to a quarter mile or less for 2 hours in the early morning of the 27th, then shortly again for less than one hour later that morning. Similar conditions were also observed by the web cam at the McDonalds MT-13 DOT site (MTMCD).
At the Navajo MT-5 DOT site (MTRED), the web cam showed visibility dropped to a quarter mile or less for about 3 hours on the morning on the 5th. Times are estimated.
At the US-2 @Stateline DOT site (MTSTA), the web cam showed visibility dropped to a quarter mile or less for about 2 1/2 hours on the morning on the 27th. Times are estimated.
At the Plentywood airport mesonet site (KPWD), visibility dropped to a quarter mile or less for about 2 hours in the early morning of the 27th. Similar conditions were observed by the web cam at the Comertown Turn-Off MT-5 DOT site.
At the Glasgow airport ASOS site (KGGW), visibility dropped to a quarter mile or less for more than 4 hours in the early morning of the 27th.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2021Every state in 2021This day in weather historyWarnings in Montana, March 2021
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: 948366, 948357, 948358, 948349, 948367.