The combination of instability and lift from terrain aided in development of isolated to scattered thunderstorms over a few afternoons.
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.
The combination of instability and lift from terrain aided in development of isolated to scattered thunderstorms over a few afternoons.
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 Aug 28, 2:01 PM MST, 1 hour 29 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 301 PM MDT Wed Aug 28 2013 .DISCUSSION... This Afternoon through Friday Evening...Weak upper level trof and band of mostly Pacific moisture currently along/east of the Continental Divide is setting off scattered showers and moderate, short-lived thunderstorms. Low- and mid-level wind shear remains marginal to weak, so main threats from these storms will be locally heavy rain and outflow winds gusting 45-50 mph. Some small hail will also be possible with a few cells. Given steady progress of the trof to this point, storms should taper off over southwest MT and areas west of Interstate 15 by 4-5 pm and then end over remainder of central and Hiline counties by 8-9 pm. Dry conditions expected overnight through tomorrow evening, when a slightly stronger shortwave trof from the low pressure area parked along the PacNW coast approaches from the west. Instability and moisture ahead of the trof axis will bring another round of scattered showers and storms Thurs night into Fri, with latest forecast models indicating best chance of storms shifts more north toward the Hiline tomorrow night. Models have been consistent past two days in showing the trof skirting the US/Can border during the daytime hours on Fri, with a weak surface front and cooler airmass dropping into central MT Fri eve. Once this disturbance moves downstream Fri eve, upper level ridging amplifies strongly across the northern Rockies with little chance of any precipitation through this weekend. Today's trof is not strong enough to change our continued run of above-average temperatures, so look for upper 80s to mid 90s again tomorrow. More extensive cloud cover and initial cooling with the second weather system will drop highs back into the mid-upper 80s on Friday. Waranauskas Friday Night through Wednesday...A weak cool front will bring temperatures closer to seasonal averages for Saturday. While an isolated shower or thunderstorm in the higher terrain is possible with this front on Friday night, most areas will remain dry. A ridge of high pressure will build into the area on Saturday with mainly dry and warm conditions expected through the first half of the Labor Day holiday weekend. As the ridge axis shifts east of the Treasure State on Sunday, moist southwest flow aloft will return to the area with above average temperatures and increasing precipitation chances. Most of the forecast area should remain dry on Sunday, and for now have kept only a slight chance of showers and thunderstorms across southwest Montana, but this could change depending on the timing of the next shortwave. Long-range forecast models continue to show good agreement with developing a closed low off of the Pacific Northwest with weak embedded shortwaves moving through the Snake River Plain into Montana which will allow for increased moisture and instability across north-central and southwest Montana on Labor Day. Thus have raised pops for Labor Day to chance in the mountains and slight chance in the plains and southwest valleys. Both the ECMWF and GFS ensembles show significant differences as the low tracks inland starting on Tuesday. Have continued to keep at least a slight chance of precipitation across the area through the middle of the week with high temperatures around 5 degrees above seasonal averages. MLV && .AVIATION... UPDATED 1745Z. Scattered showers and thunderstorms will move through the region through 06z Thursday. Some storms could produce brief gusty winds and heavy rainfall. Areas of smoke could reduce visibilities at times...especially distant mountain peaks/passes. Generally VFR conditions will prevail overnight and through Thursday morning. Another round of thunderstorms is possible again on Thursday afternoon/evening. Brusda && .FIRE WEATHER... An unstable southwesterly flow aloft will continue over the area today and Thursday with a few afternoon and evening thunderstorms. Thunderstorms should be primarily wet type with localized moderate to heavy rain and gusty outflow winds. Minimum relative humidities will drop into the teens to low 20s again tomorrow but winds should remain light so critical fire weather conditions are not expected over the next 24 hours. Waranauskas && .PRELIMINARY POINT TEMPS/POPS... GTF 59 92 59 87 / 30 10 30 10 CTB 55 90 57 82 / 20 10 30 10 HLN 58 90 58 88 / 20 10 20 10 BZN 53 88 52 89 / 20 10 10 10 WEY 44 79 44 81 / 30 20 10 10 DLN 52 84 52 86 / 20 20 20 10 HVR 59 93 59 88 / 30 10 30 10 LWT 57 89 57 85 / 30 10 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && SHORT TERM...WARANAUSKAS LONG TERM...MLV AVIATION...BRUSDA weather.gov/greatfalls
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 408 AM MDT WED AUG 28 2013 MTZ008>015-044>055-291015- BEAVERHEAD-NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL- CASCADE-CHOUTEAU-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON- TOOLE-LIBERTY-EASTERN PONDERA-BLAINE- SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-JUDITH BASIN-FERGUS- JEFFERSON-BROADWATER-MEAGHER-GALLATIN- 408 AM MDT WED AUG 28 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREAT FALLS MT 308 PM MDT WED AUG 28 2013 MTZ013-047-051-282200- BLAINE MT-CHOUTEAU MT-FERGUS MT- 308 PM MDT WED AUG 28 2013 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN FERGUS...EASTERN CHOUTEAU AND SOUTHWESTERN BLAINE COUNTIES UNTIL 400 PM MDT... AT 305 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 13 MILES WEST OF WINIFRED...OR 40 MILES NORTH OF LEWISTOWN...MOVING NORTHEAST AT 30 MPH. HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN AND FREQUENT DANGEROUS LIGHTNING. * LOCATIONS IMPACTED INCLUDE... WINIFRED... IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A STURDY BUILDING. LAT...LON 4809 10936 4773 10891 4746 10961 4772 10989 TIME...MOT...LOC 2108Z 232DEG 24KT 4764 10962 COULSTON
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
312 PM MDT WED AUG 28 2013
MTZ015-055-282200-
GALLATIN MT-MADISON MT-
312 PM MDT WED AUG 28 2013
...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN GALLATIN AND EXTREME
NORTHEASTERN MADISON COUNTIES UNTIL 400 PM MDT...
AT 310 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 7 MILES WEST OF BELGRADE...OR 14 MILES WEST OF
BOZEMAN...MOVING NORTHEAST AT 25 MPH.
WIND GUSTS UP TO 45 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH
HEAVY RAIN...FREQUENT DANGEROUS LIGHTNING...AND PEA SIZED HAIL.
* LOCATIONS IMPACTED INCLUDE...
MANHATTAN...
BELGRADE AND BOZEMAN...
IF THREATENING WEATHER APPROACHES YOUR AREA...TAKE SHELTER IN A
STURDY BUILDING.
LAT...LON 4580 11155 4617 11101 4592 11077 4575 11078
4555 11126
TIME...MOT...LOC 2112Z 234DEG 21KT 4574 11130
COULSTONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
339 PM MDT WED AUG 28 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0314 PM TSTM WND GST 1 NE BELGRADE 45.79N 111.16W
08/28/2013 M46 MPH GALLATIN MT ASOS
46 MPH THUNDERSTORM WIND GUST REPORTED BY ASOS AT
BOZEMAN YELLOWSTONE AIRPORT. BRIEF HEAVY RAIN ALSO
REPORTED.
&&
COULSTONPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
340 PM MDT WED AUG 28 2013
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0318 PM TSTM WND GST MALMSTROM AFB 47.51N 111.18W
08/28/2013 M46 MPH CASCADE MT ASOS
46 MPH THUNDERSTORM WIND GUST REPORTED BY ASOS AT
MALMSTROM AFB.
&&
COULSTONSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
404 PM MDT WED AUG 28 2013
MTZ047-051-282230-
BLAINE MT-FERGUS MT-
404 PM MDT WED AUG 28 2013
...SIGNIFICANT WEATHER ADVISORY FOR EXTREME NORTHERN FERGUS AND
SOUTHWESTERN BLAINE COUNTIES UNTIL 430 PM MDT...
AT 400 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 14 MILES NORTH OF WINIFRED...OR 46 MILES
SOUTHEAST OF BIG SANDY...MOVING NORTHEAST AT 20 MPH.
HAIL UP TO ONE-QUARTER INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH
ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.
* LOCATIONS IMPACTED INCLUDE...
RURAL NORTHERN FERGUS COUNTY...
RURAL SOUTHWESTERN BLAINE COUNTY...
LAT...LON 4768 10926 4781 10952 4799 10952 4811 10908
4794 10881
TIME...MOT...LOC 2204Z 225DEG 18KT 4778 10931
PANSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GREAT FALLS MT 409 PM MDT WED AUG 28 2013 MTZ011-047-282245- BLAINE MT-HILL MT- 409 PM MDT WED AUG 28 2013 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHEASTERN HILL AND WESTERN BLAINE COUNTIES UNTIL 445 PM MDT... AT 405 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 14 MILES SOUTHEAST OF HAVRE...MOVING NORTHEAST AT 30 MPH. HAIL UP TO ONE-QUARTER INCH IN DIAMETER AND WIND GUSTS UP TO 40 MPH ARE EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN. * LOCATIONS IMPACTED INCLUDE... CHINOOK... LAT...LON 4871 10942 4850 10904 4825 10951 4835 10973 TIME...MOT...LOC 2208Z 213DEG 25KT 4838 10954 PAN
The Great Falls radar (KTFX), 9 km away, was scanning. The volume nearest the first event began at 22:28 UTC.
16 thunderstorm wind. Local standard time, as filed.
High winds estimated at 50KT (58MPH) were reported as the cause for multiple power line breakages across Great Falls.
High winds measuring 51KT (59MPH) were reported 20 miles E of Sunburst, MT.
High winds measuring 51KT (59MPH) were reported 1 mile N of Shelby, MT.
High winds measuring 56KT (65MPH) were reported 10 miles SW of Choteau, MT.
High winds measuring 50KT (58MPH) were reported 2 miles NW of Pendroy, MT.
High winds measuring 52KT (60MPH) were reported 6 miles WNW of Dutton, MT.
High winds measuring 50KT (58MPH) were reported 3 miles W of Townsend, MT.
High winds measuring 62KT (71MPH) were reported 2 miles E of Chester, MT.
High winds measuring 52KT (60MPH) were reported at the Chester, MT courthouse.
High winds estimated at 50KT (58MPH) were reported to have damaged an airplane and a hangar in Chester, MT.
High winds measuring 57KT (66MPH) were reported 13 miles S of Harlem, MT.
High winds measuring 58KT (67MPH) were reported 13 miles W of Big Sandy, MT.
High winds measuring 52KT (60MPH) were reported 1 mile N of Loma, MT.
High winds measuring 60KT (69MPH) were reported 1 mile NE of Big Sandy, MT.
High winds measuring 62KT (71MPH) were reported 4 miles W of Havre, MT.
High winds measuring 60KT (69MPH) were reported 1 mile SE of Big Sandy.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2013Every state in 2013This day in weather historyWarnings in Montana, August 2013
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: 474900, 474903, 474904, 474905, 474906, 474907, 474914, 474908, 474909, 474901, 474915, 474910, 474911, 474912, 474913, 474902.