A line of showers and thunderstorms develop east of the Southern Rocky Mountain Front and move northeastward across the area. These storms move into a moist environment with good jet dynamics, wind shear, and instability.
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 TFX wrote it up.
A line of showers and thunderstorms develop east of the Southern Rocky Mountain Front and move northeastward across the area. These storms move into a moist environment with good jet dynamics, wind shear, and instability. As a result, a severe thunderstorm watch is issued for most of the CWA. The primary thunderstorm threats are severe hail of equal to or greater than quarter size and wind gusts of up to 60 to 80 mph. Heavy downpours of rain are also expected.
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, 10:31 AM MST, 2 hours 40 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 1131 AM MDT Thu Jun 27 2019 AVIATION SECTION UPDATED... .UPDATE... The morning update has been published. Grid edits were kept at minimum as the current forecast has a good handle on the situation. Patchy fog was extended for a couple more hours in north- central sections and some minor edits were made to pops. Still on track for scattered to numerous showers and thunderstorms to develop over central and north-central Montana this afternoon and evening. The current setup has favorable conditions for severe thunderstorm development in terms of moisture, wind shear, and jet dynamics. One factor that can slow things down a bit is the presence of cloud cover this morning, which can impede daytime heating and instability. However, there should be some periods of sunshine to get the destabilization process going as the day progresses and the current dynamics are strong enough to overcome some lack in diurnal heating. Thunderstorm threats for today will be large hail (up to the size of quarters or larger), damaging wind gusts up to 80 mph, heavy downpours, and frequent lightning. This shower and thunderstorm activity will likely develop over the Rocky Mountain Front around noon or shortly after and then spread east and northeast from there. Note that storms could develop ahead of the main line once the activity begins to take off. Most showers and storms should move out of the area or diminish by late this evening. && .SYNOPSIS... Unstable southwesterly flow aloft and embedded disturbances should affect our region through the middle of next week. Scattered to numerous showers and thunderstorms are expected today. Some of these storms should become severe. 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. Temperatures should be near or slightly below-normal over the next seven days. && .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. && .PREV DISCUSSION... /ISSUED 506 AM MDT Thu Jun 27 2019/ Today...Southwesterly flow aloft and embedded shortwave disturbances affect our region as our CWA remains east of a longwave trough axis. A mid- to upper-level low pressure center embedded within this longwave trough is progged to move north-northeastward from offshore northwestern OR to near Seattle by the end of today. The southwesterly flow aloft remains strong over our CWA as the longwave trough and embedded low interact with a nearly-stationary longwave high pressure ridge over/near the central U.S. In addition, this southwesterly flow aloft will continue to tap into abundant moisture from the Pacific. In the low-levels, flow is expected to be predominantly easterly, especially in north-central MT, and this easterly flow will tap into abundant moisture originating over the Gulf of Mexico. This pattern will contribute to the development of scattered to numerous showers and thunderstorms, especially this afternoon and evening, given daytime heating of higher terrain will be a primary mechanism for initiation of showers and storms. Unusually-high humidity will allow showers and thunderstorms to produce downpours. Localized flash flooding may occur today, particularly where showers and storms manage to train (i.e. follow the same path). WPC has outlined a marginal risk of flash flooding for all of north-central MT. However, refrained from issuing a Flood Watch since there is much disagreement between different higher- resolution models as to where hourly rain rates may be heavy enough to cause flash flooding. Strong vertical wind shear will contribute to the potential of severe thunderstorms today, especially in north-central MT, where easterly low-level winds will veer to southwesterly and strengthen with height, resulting in enhanced vertical wind shear. Some of these severe storms will likely be supercells (i.e. rotating thunderstorms). However, partly to mostly cloudy skies may limit daytime heating and atmospheric destabilization. Even so, SPC still has nearly the entire CWA highlighted in a risk of severe thunderstorms, including an enhanced risk (level 3 on a scale to 5) for much of north-central MT. Suspect there will be enough breaks in the cloud cover to allow at least moderate instability to materialize across much of our CWA during this afternoon through early evening. Hail the size of quarters to perhaps baseballs and damaging wind gusts of 60 to 80 mph remain the primary severe threats. However, a few tornadoes remain possible east of I-15 in north-central MT, especially from Hill County to Judith Basin County and points east. Here, cumulonimbus cloud bases may be favorably-low and low-level vertical shear may be sufficiently-strong for a tornadic supercell or two. The late afternoon through early evening timeframe should be the preferred window for potential tornadoes. Temperatures will be near or slightly below-normal. 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 && .PRELIMINARY POINT TEMPS/POPS... GTF 74 50 74 51 / 100 70 20 30 CTB 69 45 71 45 / 90 60 10 20 HLN 77 50 77 51 / 80 40 30 20 BZN 81 48 78 48 / 20 20 20 20 WEY 71 38 73 39 / 0 0 0 10 DLN 74 46 73 46 / 30 10 10 10 HVR 80 51 76 51 / 100 90 20 50 LWT 76 48 74 49 / 50 40 50 50 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && http://www.weather.gov/greatfalls
Special Weather Statement National Weather Service Great Falls MT 848 AM MDT Thu Jun 27 2019 MTZ012-013-049-050-271700- Cascade-Chouteau-Eastern Teton-Judith Basin- Including the cities of Great Falls, Cascade, Belt, Kings Hill Pass, Fort Benton, Carter, Big Sandy, Fairfield, Dutton, Raynesford, Stanford, and Hobson 848 AM MDT Thu Jun 27 2019 ...Patchy dense fog continues across North-central Montana this morning... Patchy dense fog continues this morning across portions of North- central Montana. This fog may persist for another hour or so. Motorists should be prepared for sudden restrictions in visibility down to less than a quarter mile at times, this includes interstate 15 through much of Cascade County. Slow down and allow extra time to reach your destination this morning.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1111 AM MDT THU JUN 27 2019
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0548 PM HAIL 4 ESE WOLF CREEK 46.99N 111.99W
06/26/2019 E0.88 INCH LEWIS AND CLARK MT FIRE DEPT/RESCUE
FACEBOOK VIDEO OF NICKEL SIZED HAIL COVERING
THE GROUND AT HOLTER LAKE CAMPGROUND.
&&
JAASpecial Weather Statement
National Weather Service Great Falls MT
133 PM MDT Thu Jun 27 2019
MTZ008-272000-
Beaverhead MT-
133 PM MDT Thu Jun 27 2019
...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL BEAVERHEAD COUNTY
UNTIL 200 PM MDT...
At 133 PM MDT, Doppler radar was tracking a strong thunderstorm 19
miles west of Divide, or 24 miles southwest of Anaconda, moving
northeast at 55 mph.
Half inch hail and winds in excess of 40 mph will be possible with
this storm.
Locations impacted include...
Wise River.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.
&&
LAT...LON 4584 11325 4588 11322 4587 11319 4588 11310
4586 11308 4581 11300 4580 11293 4569 11311
4581 11330
TIME...MOT...LOC 1933Z 224DEG 46KT 4581 11314
MoldanSpecial Weather Statement
National Weather Service Great Falls MT
141 PM MDT Thu Jun 27 2019
MTZ014-048-272000-
Southern Rocky Mountain Front MT-
Central and Southern Lewis and Clark MT-
141 PM MDT Thu Jun 27 2019
...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL LEWIS AND CLARK AND
SOUTHWESTERN TETON COUNTIES UNTIL 200 PM MDT...
At 141 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 14 miles west of Augusta to 12 miles southeast
of Lincoln. Movement was northeast at 40 mph.
Half inch hail and winds in excess of 40 mph will be possible with
these storms.
Locations impacted include...
Augusta, Nilan Reservoir, Bean Lake and Pishkun Reservoir.
A Severe Thunderstorm Watch remains in effect until 800 PM MDT for
north central and west central Montana.
LAT...LON 4788 11239 4692 11213 4670 11253 4683 11253
4684 11257 4753 11275
TIME...MOT...LOC 1941Z 222DEG 33KT 4749 11270 4681 11252
MoldanThe Great Falls radar (KTFX), 110 km away, was scanning. The volume nearest the first event began at 20:13 UTC.
21 thunderstorm wind, 6 hail, 1 tornado. Local standard time, as filed.
Wind gust of 66 MPH measured at the MacDonald Pass DOT sensor.
Second hand report of quarter size hail reported in Clancy by KRTV.
Thunderstorm wind gust of 62 MPH near the MDT Dearborn sensor.
One inch hail measured.
Quarter size hail reported on the northwest side of Great falls.
Wind gust of 50 kts/58 mph measured.
Wind gust estimated to be at least 70 mph. Power outage. Knocked over trees onto houses on 4th Avenue South.
Wind gust estimated to be at least 70 mph. Power outage. Knocked over trees onto houses on 4th Avenue South.
Social media post on KRTV weather page.
Wind gust of 50 kts/58 mph measured.
K1BM bravo awos station.
Tornado near Benchland at 510 PM. Classified as an EF0 Tornado with a peak wind estimated between 75 and 85 MPH. It was 400 yards wide and was on the ground for about a quarter of a mile. The tornado lifted near 515 PM.
One inch hail measured.
Wind gust of 54 kts measured.
Wind gust of 50 kts/58mph measured and reported.
Measured wind gust of 67 kts.
Estimated gust of 52 kts.
Measured wind gust of 51 kts.
Measured wind gust of 50 kts.
Havre AP khvr asos station.
Measured wind gust of 60 kts. Time estimated from radar.
Spotter reports at least on tree down partially blocking a road south of Chinook.
Measured north of Chinook near the Canadian border. Storm is showing signs of rotation with wall cloud, but not dropping anything at the moment. Truck windshield damaged.
Wind gust measured 54 kts.
Measured wind gust of 50 kts at awos station ks71 Chinook Apt.
Electricity outage occurred.
Measured wind gust of 64 kts at mesonet station fblm8 Fort Belknap raws.
Aerial photo and damage indicate a macroburst went through this region. Damage path was over 5 miles long. Wind Speed estimated between 70 and 90 mph. New mobile home windows bowed in. Insulation pulled out under roof. 12 large T.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2019Every state in 2019This day in weather historyThe tornado archive for Montana, 2019Warnings 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: 836521, 836508, 836522, 836509, 836510, 836523, 836515, 836524, 836511, 836525, 836526, 836514, 836512, 836527, 836528, 836529, 836530, 836531, 836532, 836533, 836534, 836516, 836513, 836535, 836536, 836518, 836537, 836520.