Similar to the previous day, and shifted further toward the southeast, an approaching cold front combined with warm moist air and an unstable atmosphere to develop and sustain severe thunderstorms through some eastern Montana locations during the evening hours.
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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.
Similar to the previous day, and shifted further toward the southeast, an approaching cold front combined with warm moist air and an unstable atmosphere to develop and sustain severe thunderstorms through some eastern Montana locations during the evening hours.
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 5, 1:46 PM MST, 4 hours 22 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 246 PM MDT Sat Jun 5 2021 .DISCUSSION... ...High fire danger and severe weather risk are concerns for portions of NE Montana today... Thunderstorms have developed again today over Montana's south central mountains. Compared to yesterday, the threat for severe impacts are shifted a bit further toward the southeast. Conditions are more favorable for damaging winds and large hail the further east the storms travel this afternoon and evening. Not at lot of CAPE, but a deeply mixed atmosphere and strong daytime heating have resulted in steep lapse rates, especially along and south of MT Highway 200. Overnight tonight through Sunday morning, the actual cold front will bring some noticeable relief to the region in the form of cooler air from the west. The associated winds along and behind the cold front will be strong and gusty enough to warrant a Lake Wind Advisory during the morning and mid-day hours. As the daily relative humidity values drop into the teens, the gusty winds diminish to less than 15 kts. Main fire weather concerns for this day seem to have shifted east of the Montana/North Dakota border. Sunday-Tuesday: Comfortably warm temperatures, light winds and sunny skies will prevail. The overall flow aloft will remain generally from the southwest or south with minor disturbances of little impact. Our attention starts to turn to a more active weather period by mid- week. By Wednesday, we are expecting daytime high temperatures in the mid to upper 80s and afternoon dewpoints in the mid 50s to lower 60s. Models are hinting at the increased chances for efficient thunderstorms. Overall weather pattern remains generally stagnant with a deep low pressure trough over the US west coast and a strong ridge of high pressure over the central plains. This places our region in- between under either southwesterly or southerly flow aloft for several days. && .AVIATION... VFR will prevail, but brief IFR is possible with area showers and thunderstorms that pass over TAF locations. Look for isolated to scattered showers and thunderstorms this afternoon and evening with associated reduced visibility and ceilings. A storm or two may be severe from KGDV to KSDY. A cold front will spread through the region beginning late tonight and through Sunday. Expect west winds at 5 to 15 kts with gusts to 25 kts. Stronger, shifting winds are likely near any thunderstorms. Late tonight through Sunday mid-day, stead west winds of 20 to 25 kts are expected behind the cold front. && .FIRE WEATHER... High fire danger has led to a Red Flag Warning issuance for Fire Weather Zones 120 and 134 for today. The combination of humidity as low as 15 percent and west winds 15 to 25 mph with gusts to 35 mph will raise these concerns. Wind speeds will be less to the south, where the overall threat is lower. Fire Weather Zone 135 was considered with gusty winds expected there, however, increasing cloud cover and rising humidity levels during the afternoon should minimize the risks there. && .GLASGOW WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 9 PM MDT this evening for MTZ120-134. Lake Wind Advisory from 6 AM to 2 PM MDT Sunday For Fort Peck Lake for Central and Southeast Phillips...Central and Southern Valley...Garfield...McCone...Petroleum. && weather.gov/glasgow
Special Weather Statement National Weather Service Glasgow MT 438 PM MDT Sat Jun 5 2021 MTZ022-052345- Garfield MT- 438 PM MDT Sat Jun 5 2021 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN GARFIELD COUNTY UNTIL 545 PM MDT... At 438 PM MDT, Doppler radar was tracking a strong thunderstorm over Edwards, or 23 miles southwest of Jordan, moving northeast at 40 mph. Wind gusts of 50 to 55 mph will be possible with this storm. Locations impacted include... Jordan, Sand Springs, Cohagen, Edwards and Steve Fork. LAT...LON 4694 10744 4725 10758 4763 10662 4694 10628 TIME...MOT...LOC 2238Z 247DEG 34KT 4716 10734 NWS Glasgow / GAH
The Glasgow radar (KGGW), 145 km away, was scanning. The volume nearest the first event began at 01:06 UTC.
3 thunderstorm wind. Local standard time, as filed.
The Big Sheep Mountain RAWS site (LCFM8), recorded a 70 mph thunderstorm wind gust.
The mesonet site near Crane (D8634), recorded a 62 mph thunderstorm wind gust.
The Beaver Hill I-94 DOT site (MTBVR), recorded a 73 mph thunderstorm 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: 963662, 963664, 963665.