A large low pressure system moved north through our region, and set up the atmosphere with strong pressure differences, which allowed gusty high winds from the northwest to reach down to the surface for at least a few locations in Valley and Garfield Counties.
Every event with a place to put it; 2 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.
A large low pressure system moved north through our region, and set up the atmosphere with strong pressure differences, which allowed gusty high winds from the northwest to reach down to the surface for at least a few locations in Valley and Garfield Counties.
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 May 24, 1:13 PM MST, 7 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 213 PM MDT Mon May 24 2021 .DISCUSSION... Strong 990 mb low nearly stationary over central Saskatchewan this afternoon will move into Manitoba Tuesday morning. Showers will gradually diminish into the evening hours for the area but not the wind. Wind gusts to 55 mph are possible till about 9 pm. The shower activity will skirt northern zones Tuesday while cold air advection keeps it windy from the NW. The next system will move in from the WSW Tuesday Night with rainshowers overspreading most of the area Wednesday. At least a tenth of an inch (0.10") should dampen all but the NE zones. A dry day is in store Thursday but temps will be about 5-10 degrees cooler than normal. An upper trough then moves across the Canadian Prairies Friday with showers and maybe a thunderstorm moving across the CWA. This system will move quickly that should allow for dry conditions Saturday. Temperatures should get close to normal Friday then drop a bit Saturday before rising through the weekend. Breezy conditions Friday should diminish by Saturday. TFJ && .AVIATION... The turbulent flying conditions this afternoon will simmer a bit this evening as showers diminish. However, winds will continue overnight tonight and into Tuesday. The wind direction will turn a bit Tuesday with them coming from the NW by the afternoon and diminishing late in the day. SYNOPSIS: An upper level low over southern Alberta and Saskatchewan today will move east to Manitoba tonight and Tuesday. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Lake Wind Advisory until 6 PM MDT Tuesday For Fort Peck Lake for Central and Southeast Phillips...Central and Southern Valley... Garfield...McCone...Petroleum. && weather.gov/glasgow
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GLASGOW MT
108 PM MDT MON MAY 24 2021
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1255 PM NON-TSTM WND GST 2 E CIRCLE 47.42N 105.56W
05/24/2021 M55 MPH MCCONE MT MESONET
MESONET STATION K4U6 1.7 E CIRCLE (GTFWFO).
&&
BCBThe national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
Trained spotter at 4 SSE Whatley recorded a 63 mph wind gust at their home weather station.
At the South Sawmill Creek RAWS site (SSMM8), sustained winds around 30 mph were steady through most of the afternoon, and a 58 mph wind gust was recorded 16:08 MST.
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, May 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: 952278, 952279.