A subtle disturbance moving from southern Canada through Montana combined with a moderately unstable atmosphere and just enough warm, moist air to set of one severe thunderstorm over the Little Rocky Mountains of SW 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.
A subtle disturbance moving from southern Canada through Montana combined with a moderately unstable atmosphere and just enough warm, moist air to set of one severe thunderstorm over the Little Rocky Mountains of SW 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 Jul 24, 1:57 PM MST, 10 hours 3 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 257 PM MDT Fri Jul 24 2020 .DISCUSSION... General area of surface low pressure and instability remain across the region with higher dewpoints (mid 60s) in our eastern zones. As such, the threat for thunderstorms continue this afternoon and evening, although likely not quite a strong as yesterday's storms. Early this afternoon, thunderstorms have begun to develop over the Cypress Hills, northwest of our CWA, and the Black Hills, way southeast of our CWA. Chose to follow the slim model agreement I could find for precipitation here locally for now through overnight tonight, with some models showing more than others. Some nocturnal storms may linger through the morning hours on Saturday through our central CWA. By Saturday night, the upper-level low pressure trough departs toward the northeast, as NW aloft returns to our region. Temperatures will cool to more normal levels for this time of year. Sunday through Tuesday mid day, a moderately strong and dry ridge of high pressure will allow high temperatures to return to the 90s more most locations. A mid-ridge disturbance will cut into the flow aloft beginning late Tuesday for more chances of thunderstorms through the remainder of the week. && .AVIATION... Expected Flight Category: Mainly VFR. Synopsis: A mix of mid and high clouds will eventually form into scattered showers and thunderstorms this evening through the overnight hours, ahead of an approaching cold front. Brief IFR conditions are possible if a storm happens to pass directly over a TAF site. Winds: Light from the west this afternoon become light and variable tonight. With the arrival of the cold front finally by Saturday morning, more widespread winds from the northeast at 10 to 15 kts will prevail through most of the day on Saturday. && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && weather.gov/glasgow
The Glasgow radar (KGGW), 128 km away, was scanning. The volume nearest the first event began at 07:01 UTC.
1 thunderstorm wind. Local standard time, as filed.
At the Malta South US-191 DOT site (MTMAL), a 62 mph wind gust was measured.
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, July 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: 909736.