A line of showers and thunderstorms develops east of the Southern Rocky Mountain Front and moves northeastward. These storms move into a moist environment with good jet dynamics, wind shear, and instability.
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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 line of showers and thunderstorms develops east of the Southern Rocky Mountain Front and moves northeastward. These storms move into a moist environment with good jet dynamics, wind shear, and instability. A severe thunderstorm watch is issued for much of the CWA. Heavy downpours of rain are forecast to cause some localized flooding.
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 Jun 27, 1:52 PM MST, 1 hour 12 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 252 PM MDT Thu Jun 27 2019 .SYNOPSIS... A line of showers and thunderstorms has developed just east of the Southern Rocky Mountain Front and moving toward the northeast. Some of these storms have the potential to produce large hail and damaging winds. This activity should diminish or move out of the area by midnight. After today, isolated to scattered showers and thunderstorms are possible through the middle of next week. In addition, a few more severe storms may occur on Friday in our eastern zones. Temperatures should be near or slightly below- normal over the next seven days. && .DISCUSSION... Remainder of today and tonight...A line of showers and thunderstorms has developed east of the Southern Rocky Mountain front and is moving in a southwest to northeast direction. These storms are moving into a moist environment with good jet dynamics, wind shear, and instability. As a result, a severe thunderstorm watch has been issued for the entire CWA with the exception of Beaverhead, Gallatin, Glacier, and Madison Counties. The primary thunderstorm threat will be severe hail up to the size of quarters or larger and wind gusts up to 60 to 80 mph. Heavy downpours of rain are also expected, which could cause some localized flooding. This activity is expected to start diminishing and moving out of the area around 4Z but some isolated showers and storms will continue to linger thereafter. rcg Friday through next Wednesday...Latest deterministic and ensemble model guidance is in rather good agreement during this period. Thus, southwesterly flow aloft and embedded shortwave disturbances should continue to affect our CWA as the longwave trough axis remains to our west and the longwave high pressure ridge remains essentially anchored to our east. Isolated to scattered showers and thunderstorms are possible daily, especially during the afternoon and evening hours. In addition, a few severe thunderstorms may affect eastern portions of the CWA Friday afternoon and early evening, when moderate instability and strong vertical wind shear may exist. Temperatures should remain near or slightly below-normal. - Jaszka && .AVIATION... Updated 1130 AM MDT Thu Jun 27 2019 (18Z/27 TAF issuance) Outside of any shower/thunderstorm activity and lingering low clouds over KGTF and KCTB, mostly VFR conditions are expected for the next 24-hours. Disturbances embedded within the southwesterly flow aloft along with other dynamics will produce scattered to numerous showers and thunderstorms generally between 20Z/Thu and 04Z/Fri, while isolated lighter showers and thunderstorms are possible before and after that period. Note that Periods of MVFR/IFR may accompany any shower or storm. Some thunderstorms are still expected to become severe this afternoon and early evening, especially in central and north-central MT. Quarter-size or larger hail and erratic surface gusts of 50 to 70 knots are the primary severe threats, along with the potential for heavy downpours. Regional surface winds remain light outside outflow (i.e. precip-cooled air emanating from any shower or storm). Lastly, patchy fog may redevelop tonight over the the North-Central terminals again late tonight along with localized MVFR/IFR. && .PRELIMINARY POINT TEMPS/POPS... GTF 49 74 50 76 / 70 20 30 10 CTB 44 71 45 73 / 60 20 20 10 HLN 49 77 50 80 / 50 30 30 20 BZN 47 78 47 79 / 20 20 30 10 WEY 37 73 40 73 / 0 10 10 0 DLN 45 73 46 75 / 10 10 10 10 HVR 50 76 52 77 / 90 20 50 20 LWT 47 74 49 72 / 50 50 60 50 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && http://www.weather.gov/greatfalls
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
332 PM MDT THU JUN 27 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0240 PM HAIL 1 SE MONTANA CITY 46.52N 111.91W
06/27/2019 M0.70 INCH JEFFERSON MT TRAINED SPOTTER
ALSO, .34 INCH RAIN AND WIND GUST 20 MPH.
&&
JAFSpecial Weather Statement National Weather Service Great Falls MT 335 PM MDT Thu Jun 27 2019 MTZ012-049-272200- Cascade MT-Eastern Teton MT- 335 PM MDT Thu Jun 27 2019 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN TETON AND NORTHWESTERN CASCADE COUNTIES UNTIL 400 PM MDT... At 335 PM MDT, Doppler radar was tracking strong thunderstorms along a line extending from 6 miles north of Fort Shaw to 6 miles south of Cascade. Movement was northeast at 25 mph. Half inch hail and winds in excess of 40 mph will be possible with these storms. Locations impacted include... Cascade, Fort Shaw, Fort Shaw, Power, Ulm, First Peoples Buffalo Jump State Park and Sun River. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with these storms. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. These storms may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && A Severe Thunderstorm Watch remains in effect until 800 PM MDT for central and north central Montana. LAT...LON 4777 11164 4719 11139 4714 11170 4761 11190 TIME...MOT...LOC 2135Z 212DEG 21KT 4759 11183 4718 11168 NJL
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
338 PM MDT THU JUN 27 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0240 PM HAIL 1 SE HELENA 46.59N 112.00W
06/27/2019 E0.25 INCH LEWIS AND CLARK MT TRAINED SPOTTER
1/4 HAIL AT 21 AMBER LANE, EAST HELENA MT,
AT 2:40 PM. ALSO, .22 INCHES OF RAIN BETWEEN
2:40 AND 2:55 PM.
&&Special Weather Statement National Weather Service Great Falls MT 351 PM MDT Thu Jun 27 2019 MTZ012-013-049-272215- Chouteau MT-Cascade MT-Eastern Teton MT- 351 PM MDT Thu Jun 27 2019 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN TETON...WESTERN CHOUTEAU AND NORTHWESTERN CASCADE COUNTIES UNTIL 415 PM MDT... At 351 PM MDT, Doppler radar was tracking strong thunderstorms along a line extending from near Power to 13 miles southeast of Cascade. Movement was northeast at 45 mph. Nickel size hail and winds in excess of 40 mph will be possible with these storms. Locations impacted include... Great Falls, Black Eagle, Ulm, Eden, Vaughn, First Peoples Buffalo Jump State Park and Sun River. PRECAUTIONARY/PREPAREDNESS ACTIONS... Torrential rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. Frequent cloud to ground lightning is occurring with these storms. Lightning can strike 10 miles away from a thunderstorm. Seek a safe shelter inside a building or vehicle. These storms may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && A Severe Thunderstorm Watch remains in effect until 800 PM MDT for central and north central Montana. LAT...LON 4776 11140 4732 11115 4713 11156 4768 11186 TIME...MOT...LOC 2151Z 227DEG 38KT 4765 11174 4716 11147 NJL
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
359 PM MDT THU JUN 27 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0357 PM HAIL 4 ENE ULM 47.46N 111.43W
06/27/2019 E0.75 INCH CASCADE MT NWS EMPLOYEE
WIND GUST 36 KT.
&&
JAFPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
401 PM MDT THU JUN 27 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0359 PM TSTM WND GST 5 SSE ULM 47.37N 111.48W
06/27/2019 M42 MPH CASCADE MT TRAINED SPOTTER
&&The Great Falls radar (KTFX), 3 km away, was scanning. The volume nearest the first event began at 22:06 UTC.
4 flood, 2 flash flood. Local standard time, as filed.
Three to four inches of water observed flowing across I-15.
One foot of water observed flowing across Central Ave.
One foot of water observed flowing across Central Ave.
Landslide occurring on River Drive.
Spotter's basement flooded by brief heavy rainfall; however, relative in Denton proper did not have flooding.
Water on Roads near the northwest bypass. Relayed by media.
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, June 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: 836949, 836950, 836951, 836947, 836952, 836948.