A large scale trough draped over the western 1/3rd of the US, with the axis |generally orientated northeast to southwest from Western Montana. At the surface, a weak area of low pressure developed east of the Continental Divide over Central |Montana during the afternoon, while a cold front over Alberta quickly dropped south along the eastern slopes of the Rockies.
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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 TFX wrote it up.
A large scale trough draped over the western 1/3rd of the US, with the axis |generally orientated northeast to southwest from Western Montana. At the surface, a weak area of low pressure developed east of the Continental Divide over Central |Montana during the afternoon, while a cold front over Alberta quickly dropped south along the eastern slopes of the Rockies. Precipitable water values ranged from around .5 to .75 inches and there was a modest amount of cape and shear present. Showers and thunderstorm activity generally remained confined to the areas of best synoptic forcing over Central and Southwest Montana. One storm near the community of Buffalo produced heavy rain that resulted in flooding of the Buffalo Creek.
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 Great Falls, MT wrote its last area forecast discussion before the first event at Jul 4, 4:40 PM MST, 1 hour earlier.
Area Forecast Discussion National Weather Service Great Falls MT 540 PM MDT Thu Jul 4 2019 Updated Aviation Section .SYNOPSIS... A cold front moves south across north-central Montana this afternoon and evening, bringing breezy northerly winds with a few gusts to the plains of North Central Montana. Scattered showers and thunderstorms are expected over Southwest Montana for much of the day, and along the Rocky Mountain Front and extending across parts of the Hi- Line this afternoon and evening. && .DISCUSSION... Rest of this Afternoon through Friday... Primary concern over the period are showers and thunderstorms, along with a period of breezy winds that will follow the passage of cold front this afternoon and evening. Mid-level cyclonic flow continues with disturbances located from western and central Montana extending south and southwest through much of Idaho. At the surface, a weak area of low pressure will develop east of the Continental Divide over Central Montana this afternoon, all the while a cold front and associated area of high pressure over Alberta quickly builds south along the eastern slopes of the Rockies. 6hr pressure rises behind the cold front of approximately 3mb will lead to brief period of breezy to occasionally gusty northwest-to-northerly winds this afternoon and evening, especially along and west of the Interstate 15 corridor. The best coverage of showers and thunderstorms the remainder of this afternoon into early evening will generally remain confined southeast of a Helena to Lewistown line where the best synoptic forcing will reside, and along the Rocky Mountain Front late this afternoon and evening as upslope flow develops thanks to the southward advancing cold front. Additional isolated showers/storms are possible across the remainder of the region, but this activity will be very isolated and mostly driven from peak heating/steep lapse rates (thanks to anomalously cold mid- to upper level temperatures)/orographic lift. Those planning on recreating outdoors are encouraged to keep an eye to the sky through this evening as any thunderstorm will be capable of producing cloud-to-ground lightning. Low- to mid-level moisture pooling behind the passage of the cold front this evening will lead an increasing stratus deck over North Central Montana mainly beginning during the overnight period(especially along eastern and northern facing slopes and foothills), while Southwest Montana generally sees clearing skies thanks to large scale subsidence behind the departing through. By Friday morning, the next H500 trough and closed low will begin to dig southwest into the Pacific Northwest, with moist southwest flow remaining over the Northern Rockies and embedded waves lifting northeast through the flow. In the low levels over North Central Montana, northerly to easterly upslope flow will continue, which combined with forcing from the embedded waves lifting northeast within the moist southwest flow will lead to scattered to numerous showers over the plains and mountains of North Central Montana (especially during the afternoon and evening hours). Across Southwest Montana, precipitation chances will be highest over the mountains thanks to orographic lift, but some valley showers/storms can't be ruled out. Saturday through Thursday... Unsettled conditions are expected to continue through the weekend and Tuesday as the H500 trough and closed low remains relatively anchored over the Pacific Northwest/Southern British Columbia, with moist southwest flow pumping bountiful Pacific moisture into the the Northern Rockies. While this period will not be washout by any means, daily chances for showers and thunderstorms will exist, especially over the higher terrain and in proximity to north/east facing upslope areas of North Central Montana. - Moldan && .AVIATION... Updated 540 PM MDT Thu Jul 4 2019 (00Z TAF issuance) Showers and thunderstorms are expected to continue through this evening over parts of southwest and north-central Montana, with some terminals experiencing MVFR to IFR conditions in some of the heavier showers. A Canadian cold front will continue to track through Central Montana this evening, shifting winds to more northerly in its wake as it tracks southeastward through the area. This cold front will also bring periods of breezy northerly winds with a few gusts in the 20 to 25 mph range, and eventually lowering ceilings to MVFR/IFR to terminals across north-central Montana during the overnight period. Isolated to scattered showers and perhaps a few weak thunderstorms will also be possible over north-central Montana behind the front through the early overnight hours. Mountain obscuration will likely continue over Southwest Montana through this evening, and then during the overnight hours over north-central Montana following the passage of the cold front. -TP && .PRELIMINARY POINT TEMPS/POPS... GTF 49 71 51 81 / 20 40 30 30 CTB 47 67 46 77 / 50 50 30 60 HLN 51 75 51 83 / 20 50 30 40 BZN 47 75 48 82 / 40 40 20 10 WEY 37 71 38 77 / 10 30 20 10 DLN 44 73 47 78 / 50 30 20 20 HVR 51 73 52 81 / 20 60 40 20 LWT 47 68 48 76 / 20 60 40 40 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && http://www.weather.gov/greatfalls
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Floodwater was flowing across property on West Buffalo Creek. The Floodwaters were up to four feet deep and the floodwater channel was about 100 yards wide.
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 2026-09-24. Each event’s entry at NCEI: 844311.