A passing upper level trough and surface Canadian cold front combined to result in a few showers and thunderstorms where the front stalled a bit across the Hi-Line. Winds along the front were already on the breezy side, so additional nudges from thunderstorms along the front were sufficient to result in gusts in excess of 58 mph.
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 passing upper level trough and surface Canadian cold front combined to result in a few showers and thunderstorms where the front stalled a bit across the Hi-Line. Winds along the front were already on the breezy side, so additional nudges from thunderstorms along the front were sufficient to result in gusts in excess of 58 mph.
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 20, 12:40 PM MST, 50 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 140 PM MDT Fri Sep 20 2024 .SYNOPSIS... This afternoon there will be showers and thunderstorms primarily along the Hi-Line. This afternoon through this evening it will be windy in North-central Montana with the strongest winds along the Rocky Mountain Front over to the Hi-Line. Tomorrow morning it will be cold with numerous lower-elevation locations seeing frost. An upper-level shortwave will bring precipitation chances to the area Sunday evening through Monday. A ridge builds into the area on Tuesday which will bring warm temperatures and dry conditions for the middle of next week. && .DISCUSSION... This afternoon through Saturday...A cold front is moving south from Canada. This will bring showers and thunderstorms to the Hi-Line this afternoon through this evening. The showers will slowly spread south to the rest of North-central Montana by midnight tonight before they fizzle out. An isolated thunderstorm along the Hi-Line will produce strong to severe wind gusts. The Storm Prediction Center has issued a Marginal Risk (5% chance within 25 miles of a point)for severe wind gusts along the Hi-Line today. The Hi-Line has a 15 - 30% chance for seeing a tenth of an inch of rain or greater through midnight tonight. The front combined with an upper-level shortwave trough is bringing strong winds to North- central Montana. The strongest winds will be along the Rocky Mountain Front over to the Hi-Line where gusts of 40 to 50 mph are expected. The Rocky Mountain Front and adjacent plains have a 50 - 80% chance for winds of 47 mph or greater through midnight tonight. The cold front and upper-level shortwave trough will lower snow-levels to 5500 feet in Glacier National Park. Areas at 5500 feet and above are likely to see a dusting of snow this afternoon through Saturday morning. There is a 20% chance for patchy fog to form in some valley locations Saturday morning. Surface high pressure moves over North-central, Central, and Southwestern Montana on Saturday. This combined with the cold front will bring cold temperatures and clear skies to the area. This will result in numerous lower-elevation locations across North-central, Central, and Southwestern Montana having frost. Saturday morning will be the coldest morning of this early fall period. On Saturday morning lower-elevations of Southwestern Montana and the Cut Bank area have a 10 - 30% chance of seeing low temperatures of 32 degrees or colder. Sunday through Tuesday...On Sunday the upper-level ridge remains over North-central, Central, and Southwestern Montana. Then late Sunday afternoon an upper-level shortwave moves through the flow. This will bring precipitation chances to North-central, Central, and Southwestern Montana. On Sunday temperatures will warm up to slightly above seasonal averages. Sunday morning it will be cold with some valley locations of Southwestern Montana seeing frost. On Sunday morning lower-elevations of Southwestern Montana have a 10 - 25% chance of seeing low temperatures of 32 degrees or colder. On Monday the upper-level shortwave remains over the area for most of the day. This will cool temperatures back down to about seasonal averages with precipitation chances for North- central, Central, and Southwestern Montana. Sunday through Monday there is a 10 - 30% chance for a tenth of an inch of rain or greater across North-central, Central, and Southwestern Montana. On Tuesday an upper-level ridge moves over North-central, Central, and Southwestern Montana. This will bring dry and warm weather to the area. Temperatures look to be up to 10 degrees above seasonal averages. -IG Wednesday through next Friday... The latest 3 to 7 day cluster analysis unanimously agree with high pressure aloft building over the Northern Rockies by the middle of the workweek for a return to well above normal temperatures and dry conditions. Over 60% of ensemble suites flatten the ridge by next weekend while the remaining members more or less maintain its strength. Additional opportunities for breezy to windy conditions, cooling temperatures, and shower chances can be expected should the ridge become compromised. Otherwise, the less likely scenario will be a continuation of dry conditions and above normal temperatures. - RCG && .AVIATION... 20/18Z TAF Period A fast moving disturbance will bring lowering CIGS and chances for showers to the plains of Central and North Central Montana this afternoon and evening. While low-VFR/VFR conditions are predominately expected across all terminals through the 2018/2118 TAF period, periods of MVFR conditions are possible at the KCTB, KHVR, KGTF, and KLWT terminals through this evening, and potentially into the morning hours on Saturday in northerly upslope favored locations (i.e. KGTF and KLWT terminals). In addition to the chances for showers, breezy and gusty southwest to northwest winds will occur across all of Southwest through North Central Montana this afternoon and through 00-03z Saturday, with the strongest winds developing over the plains of Central and North Central Montana. Mountain wave turbulence is possible across all of the Northern Rockies. Mountain obscuration is likely through 12z Saturday over Central and North Central Montana. Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .HYDROLOGY... The river gauge at Clear Creek near Chinook crested at 5.3 ft during the overnight hours and went back up to near Minor Flood stage at 5.5 ft this morning. As a result a Flood Warning has been issued through 6 PM tonight. -IG/RCG && .PRELIMINARY POINT TEMPS/POPS... GTF 71 35 62 39 / 20 30 0 0 CTB 64 32 61 35 / 50 40 0 0 HLN 70 39 66 40 / 0 0 0 0 BZN 72 34 63 34 / 0 0 0 0 WYS 61 27 62 26 / 0 10 0 0 DLN 70 33 61 34 / 0 0 0 0 HVR 65 39 62 36 / 50 20 0 0 LWT 69 34 58 36 / 10 10 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && http://www.weather.gov/greatfalls
Special Weather Statement
National Weather Service Great Falls MT
1205 PM MDT Fri Sep 20 2024
MTZ303-304-201845-
Eastern Toole and Liberty MT-
Eastern Glacier, Western Toole, and Central Pondera MT-
1205 PM MDT Fri Sep 20 2024
...GUSTY SHOWERS WILL IMPACT NORTHEASTERN GLACIER AND NORTHWESTERN
TOOLE COUNTIES THROUGH 1245 PM MDT...
At 1204 PM MDT, Doppler radar was tracking gusty showers 13 miles
west of Sunburst, or 18 miles north of Cut Bank, moving east at 30
mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Sunburst, Kevin, Ferdig, Oilmont, and Santa Rita.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4899 11218 4899 11151 4853 11173 4881 11248
4901 11228
TIME...MOT...LOC 1804Z 288DEG 25KT 4889 11221
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
MoldanSpecial Weather Statement
National Weather Service Great Falls MT
1248 PM MDT Fri Sep 20 2024
MTZ303-304-201930-
Eastern Toole and Liberty MT-
Eastern Glacier, Western Toole, and Central Pondera MT-
1248 PM MDT Fri Sep 20 2024
...A STRONG THUNDERSTORM WILL IMPACT NORTHEASTERN GLACIER AND
NORTHWESTERN TOOLE COUNTIES THROUGH 130 PM MDT...
At 1248 PM MDT, Doppler radar was tracking a strong thunderstorm 24
miles north of Cut Bank, moving southeast at 25 mph.
HAZARD...Wind gusts of 50 to 55 mph.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects.
Locations impacted include...
Sunburst and Sweet Grass.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 4900 11177 4869 11202 4893 11259 4900 11254
TIME...MOT...LOC 1848Z 295DEG 22KT 4898 11243
MAX HAIL SIZE...0.00 IN
MAX WIND GUST...55 MPH
MoldanPreliminary Local Storm Report
National Weather Service Great Falls MT
156 PM MDT Fri Sep 20 2024
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0129 PM Non-Tstm Wnd Gst 3 SW Cut Bank 48.60N 112.37W
09/20/2024 M64 MPH Glacier MT ASOS
Combination of cold front and collapsing
shower.
&&
MoldanSpecial Weather Statement National Weather Service Great Falls MT 201 PM MDT Fri Sep 20 2024 MTZ304>311-202115- Eastern Toole and Liberty-Hill County-Northern Blaine County- Southern Rocky Mountain Front-Southern High Plains- Eastern Pondera and Eastern Teton- Western and Central Chouteau County- Bears Paw Mountains and Southern Blaine- Including the cities of Devon, Shelby, Chester, Galata, Joplin, Lothair, Whitlash, Havre, Chinook, Zurich, Harlem, Hogeland, Fort Belknap, Rogers Pass, Bynum, Choteau, Pendroy, Brady, Conrad, Ledger, Floweree, Carter, Fort Benton, and Rocky Boy 201 PM MDT Fri Sep 20 2024 ...Strong and Gusty Winds... Scattered showers, and even a few thunderstorms, associated with a cold front will lead to strong and gusty west to northwest winds this afternoon. Wind gusts approaching 55 mph, locally higher, are possible as the cold front and showers pass. Be prepared for strong and gusty winds, especially if traveling in a high profile vehicle. Moldan
The Great Falls radar (KTFX), 139 km away, was scanning. The volume nearest the first event began at 20:28 UTC.
4 thunderstorm wind. Local standard time, as filed.
Mesonet station GW4063 Eagle Creek Colony measured a 55 kt gust.
An Ambinet station NE of Chester measured a 60 mph gust.
ASOS station KHVR Havre Airport measured a 54 kt gust.
ASOS station KHVR Havre Airport measured a 54 kt gust.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2024Every state in 2024This day in weather historyWarnings in Montana, September 2024
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: 1211451, 1211452, 1211453, 1211454.