A subtle weather disturbance moved through southern Saskatchewan, and combined with a hot and humid air mass to form a few severe thunderstorms which eventually crossed the border into far northeastern Montana.
Every event with a place to put it. 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 subtle weather disturbance moved through southern Saskatchewan, and combined with a hot and humid air mass to form a few severe thunderstorms which eventually crossed the border into far northeastern Montana.
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 12, 1:47 PM MST, 3 hours 43 minutes earlier.
Area Forecast Discussion National Weather Service Glasgow MT 247 PM MDT Fri Jul 12 2019 .DISCUSSION... Isolated storms will move southeast out of Canada this evening across far Northeast Montana. Cannot rule out a strong to severe storm prior to sunset. Hail to around 1 inch will be the primary threat, though some gusty winds will be possible as well. Otherwise, a few showers and storms may affect southern portions of the area this evening and tonight before likely dissipating prior to sunrise Saturday. Additional storms may develop across the area late Saturday afternoon and evening. The better chance for storms will be during the evening hours as they move off the higher terrain in Central Montana and move eastward into the area. Very steep lapse rates combined with surface dewpoints in the upper 50s to low 60s will allow for MLCAPE on the order of 1500 to 2500 J/Kg. This combined with sufficiently long hodographs suggests a good chance for some severe storms during the evening hours. Any isolated storm would possess a threat for very large hail. However, like the past several events, the more likely scenario is for these storms to congeal into more of a broken line as they traverse across Northeast Montana and provide a threat for damaging winds. The storms should be into North Dakota by around midnight or so. A cold front will move through the area Sunday evening and night, bringing another round of severe storms to Northeast Montana. The brunt of the day should be dry as the storms will most likely be focused along a surface trough located just ahead of the cold front. This would bring storms into Phillips/Petroleum County in the 4 to 6 PM time frame. These would then march eastward with the severe threat continuing into at least the early overnight hours. The amount of forcing present suggests a mostly linear evolution is expected with damaging winds the primary threat. Once again, however, if any storm is able to remain isolated, very large hail would be possible. Additional shortwaves look to move through the mean flow as we head into next week, which will mean continued chances for showers and thunderstorms. Temperatures this weekend will soar into the middle 90s with highs next week reaching the upper 80s most days. -Mottice && .AVIATION... VFR conditions tonight and tomorrow. A few showers or thunderstorms are possible, mainly for KSDY & KGDV, this evening, which could lead to brief MVFR conditions. Additional storms will move in from the west Saturday evening. -Mottice && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && weather.gov/glasgow
Special Weather Statement National Weather Service Glasgow MT 207 PM MDT Fri Jul 12 2019 MTZ023-025-026-122045- Dawson MT-Prairie MT-McCone MT- 207 PM MDT Fri Jul 12 2019 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN MCCONE... NORTHWESTERN PRAIRIE AND SOUTHWESTERN DAWSON COUNTIES UNTIL 245 PM MDT... At 207 PM MDT, Doppler radar was tracking a strong thunderstorm 11 miles south of Brockway, or 21 miles southwest of Circle, moving east at 45 mph. Penny size hail and winds in excess of 40 mph will be possible with this storm. Locations impacted include... Lindsay. LAT...LON 4704 10591 4722 10593 4732 10510 4700 10508 TIME...MOT...LOC 2007Z 266DEG 40KT 4714 10581 Mottice
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</html>The Glasgow radar (KGGW), 160 km away, was scanning. The volume nearest the first event began at 00:29 UTC.
5 hail, 4 thunderstorm wind. Local standard time, as filed.
Trained spotter reported a 12-inch diameter tree broke in half. Wind speed estimated.
Trained spotter reported quarter size hail.
The Medicine Lake RAWS site recorded a 69 mph wind gust. Time estimated by radar.
Trained spotter reported hail up to the size of quarters. Time estimated by radar.
Trained spotter measured an 84 mph wind gust.
Trained spotter reported golf ball size hail.
Public reported golf ball size hail. Time estimated by radar.
Public reported windows broken from wind-blown hail on the north side of their home. Time estimated by radar.
Trained spotter reported hail up to the size of quarters. Time estimated by radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2019Every state in 2019This day in weather historyWarnings in Montana, July 2019
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 2026-10-01. Each event’s entry at NCEI: 839811, 839817, 839840, 839866, 839869, 839872, 839894, 839898, 839899.