Strong surface winds spread across Central and North Central Montana as high pressure built in behind a low pressure system to the east. Warning level winds were observed over the Northern 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.
Strong surface winds spread across Central and North Central Montana as high pressure built in behind a low pressure system to the east. Warning level winds were observed over the Northern Rockies. Convective activity also produced a couple warning criteria outflow wind observations.
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 Sep 16, 11:00 AM MST, 2 hours 28 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 1200 PM MDT Mon Sep 16 2013 .UPDATE... Minor update this morning. A couple isolated showers may continue to form over Southwest Montana this morning but not much is expected of them. A chance of scattered thunderstorm development this afternoon remains possible with strong winds being the main danger. Temperatures will be warm once again and may be the last at or near 90 degree day for many locations. && .AVIATION... UPDATED 1800Z. Southwest flow will continue to bring moisture and instability to the area. Westerly surface winds will become gusty along the Rocky Mountain Front and adjacent plains today. Conditions will become sufficiently unstable for isolated to scattered showers and thunderstorms to develop after 21Z. VFR conditions prevail with MVFR conditions possible in the vicinity of thunderstorms. The main threat from any storms will be gusty erratic winds. Convective activity should end by 04Z at KLWT and KHVR. Conditions will be quiet overnight before degrading Tuesday afternoon. && .PREV DISCUSSION... /ISSUED 550 AM MDT Mon Sep 16 2013/ Today through Wednesday...Expect the airmass to change rather significantly over the region over the next few days...as mother nature will not wait until fall arrives this weekend before the first snow of the season arrives this week in the mountains. Today should be the last very warm day of the year...with afternoon highs in the mid to upper 80s over the region. There will be a few thunderstorms this morning along the divide and up in the Glacier Park Region...while another round of thunderstorms is expected to move eastward across the region late this afternoon through this evening. All of this thunderstorm activity should remain fairly isolated today. For Tuesday...expect cooler air to start to move into the region ahead of the Pacific cold front. However...a much stronger upper level disturbance will accompany the cold front...and a few strong storms are possible with the frontal passage. The main threat from the stronger storms will be gusty winds. On Tuesday night the cold air moves into the region along with some fairly widespread light rainfall and by Wednesday the steady precipitation should continue over North Central MT with scattered showers in the Southwest. There could be enough cold air...that snow levels could fall to around 7500 to 8000 feet over the Rocky Mountain Front on Wednesday. Thus an inch of snowfall is possible Wednesday at the higher peaks. Elsewhere Wednesday...it will be much cooler as well...with afternoon highs only in the mid 50s to lower 60s...which is about 20 to 30 degrees colder than high temps today. Brusda Wednesday night through Monday...The period begins with an upper trof exiting the area. The northeast portion of the county warning area will see the heaviest precipitation with isolated showers elsewhere. Some snow is also possible over the higher peaks. An upper ridge begins to build over the area Thursday and strengthens on Friday bringing warmer and dry conditions. By Saturday, the ridge axis is pushed east into the Upper Midwest as an upper trof approaches the Pacific Northwest. Increasing southwest flow aloft will bring moisture and instability to the area resulting in isolated afternoon and evening showers and thunderstorms. Sunday finds the upper trof pushing east across the Continental Divide bringing unsettled conditions including cooler temperatures and scattered showers. As the trof moves east on Monday, the flow aloft becomes somewhat zonal with drier air and a return of warmer air. Temperatures will be near to slightly below seasonal averages. && .PRELIMINARY POINT TEMPS/POPS... GTF 90 51 78 48 / 20 10 20 80 CTB 85 47 74 45 / 20 10 20 70 HLN 87 53 79 48 / 30 20 40 80 BZN 86 48 79 42 / 20 20 50 40 WEY 74 39 68 33 / 20 10 40 40 DLN 82 48 75 42 / 20 20 50 40 HVR 90 51 78 48 / 20 20 10 70 LWT 87 49 76 46 / 30 30 20 60 && .TFX WATCHES/WARNINGS/ADVISORIES... NONE. && weather.gov/greatfalls
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 409 AM MDT MON SEP 16 2013 MTZ008>015-044>055-171200- 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- 409 AM MDT MON SEP 16 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 FOR TODAY AND TONIGHT IS LOW. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY A PACIFIC COLD FRONT WILL MOVE THROUGH THE REGION ON TUESDAY. EXPECT A LINE OF THUNDERSTORMS TO ACCOMPANY THE COLD FRONT. SOME OF THE STORMS ON TUESDAY COULD BE STRONG...WITH THE MAIN THREAT BEING GUSTY WINDS. THEN MUCH COOLER AIR MOVES INTO THE REGION FOR WEDNESDAY. THERE IS THE POTENTIAL FOR AROUND AN INCH OF SNOWFALL WEDNESDAY FOR ELEVATIONS ABOVE 7500 FEET OVER THE ROCKY MOUNTAIN FRONT...INCLUDING THE GLACIER PARK REGION. .SPOTTER INFORMATION STATEMENT... ANY WEATHER SPOTTER REPORTS OF GUSTY THUNDERSTORM WINDS WOULD GREATLY BE APPRECIATED.
The Great Falls radar (KTFX), 188 km away, was scanning. The volume nearest the first event began at 20:28 UTC.
3 thunderstorm wind, 1 high wind. Local standard time, as filed.
Cessna was blown over while taxiing during convective outflow wind gust. Aircraft suffered structural damage but passengers were fine.
Strong winds measuring 54KT (64MPH) were reported.
Strong winds measuring 50KT (58MPH) were reported at the Havre Airport ASOS.
Strong winds measuring 56KT (65MPH) were reported at the Logan Pass Visitors Center.
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, September 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: 476316, 475723, 475724, 476314.