In a post-cold frontal environment, strong winds from aloft were just barely able to mix down the Little Rocky Mountains of southwest Phillips County.
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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.
In a post-cold frontal environment, strong winds from aloft were just barely able to mix down the Little Rocky Mountains of southwest Phillips 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 Jun 15, 2:40 PM MST, 10 hours 52 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 340 PM MDT Tue Jun 15 2021 .DISCUSSION... Triple digit temperatures are spreading across the region this afternoon under the strongest day of high pressure ridging aloft. Hard to say whether the heat alone will be enough to set off some thunderstorms this evening. The cold front is approaching from the west and it may provide the lift to do so, but most models are not convinced. Most models were also convinced that storms would not develop last night, but they did. So for this evening, chose to err on the side of caution and favor the only model showing storms this evening (CMCnh), expecting storms to develop over Prairie County, then grow in size toward the north and east overnight as they cross into North Dakota. The Excessive Heat Warning and Heat Advisory currently in effect will expire at midnight tonight. Even though high temperatures behind the cold front will drop 25 degrees compare to today, the gusty west/northwest winds will remain with only little humidity recovery. Felt it was best to issue another Lake Wind Advisory for tomorrow. Wednesday night and beyond more seasonable temperatures can be expected. Additionally, the northern stream flow directs a series of low pressure troughs and upper level disturbances in the flow which will provide some chance for precipitation, especially Saturday night through Monday night. && .AVIATION... FLIGHT CONDITIONS: VFR LLWS: Speed shear and directional shear possible with an approaching cold front tonight WINDS: SE 15-25 kts today, then shifting winds becoming NW-W 15-25 kts tonight and early Wednesday morning. SYNOPSIS: High Pressure remains in control today. A strong but relatively dry cold front moves through the area tonight. Only precipitation threat will be from a few isolated high based thunderstorms possibly for KGDV and KSDY late tonight. && .FIRE WEATHER... Today, tonight, and Wednesday will be critical fire weather periods across the region. Gusty SE winds have limited RH recovery overnight. Temperatures will be above 100 in many areas with very low RH around 7 percent west and 20-25 percent east today. A mainly dry cold front tonight will turn the winds to the NW and they will be gusty on Wednesday with low RH near 20 percent. A Red Flag Warning is in effect this afternoon, tonight and Wednesday for all of NE Montana. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until midnight MDT tonight for Central and Southeast Phillips...Central and Southern Valley...Dawson... Eastern Roosevelt...Garfield...McCone...Northern Phillips... Northern Valley...Petroleum...Prairie...Richland...Southwest Phillips...Western Roosevelt...Wibaux. Red Flag Warning until midnight MDT Wednesday night for MTZ120-122-134>137. Lake Wind Advisory until 6 PM MDT this evening For Fort Peck Lake for Central and Southeast Phillips...Central and Southern Valley...Garfield...McCone...Petroleum. Lake Wind Advisory from 1 AM to 8 PM MDT Wednesday For Fort Peck Lake for Central and Southeast Phillips...Central and Southern Valley...Garfield...McCone...Petroleum. Heat Advisory until midnight MDT tonight for Daniels...Sheridan. && weather.gov/glasgow
The national radar mosaic for the moment the first event began.
1 high wind. Local standard time, as filed.
The mesonet site at Zortman measured a 61 mph wind gust.
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, June 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: 969403.