Down-slope westerly winds increased across North-Central Montana associated with a low pressure system moving through the region. A passing shortwave and approaching upper-level jet max further increased down-slope wind strength along the Rocky Mountain Front and adjacent plains.
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.
Down-slope westerly winds increased across North-Central Montana associated with a low pressure system moving through the region. A passing shortwave and approaching upper-level jet max further increased down-slope wind strength along the Rocky Mountain Front and adjacent plains.
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 21, 4:45 PM MST, 15 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 545 PM MDT Sat Sep 21 2013 ...UPDATE TO AVIATION... .DISCUSSION... Tonight through Monday...A weak surface cold front is continuing to push through central Montana this evening with breezy southwest winds ahead of the front. While no precipitation has been noted with this system yet, isolated showers and thunderstorms are possible in higher terrain this evening. Moisture will increase late tonight and Sunday morning in response to an upper-level shortwave expected to move across southwest and central Montana. The lift associated with this shortwave will support scattered showers across the area mainly between midnight and noon on Sunday, then as downslope westerly winds increase across north-central Montana during the afternoon, precipitation will be limited. Additional shortwave energy and an approaching upper-level jet will further increase downslope winds along the Rocky Mountain Front Sunday night into Monday. Thus, have issued a High Wind Watch for the northern and southern Rocky Mountain Front beginning Sunday night through late Monday evening with sustained west winds of 30 to 40 mph and gusts up to 60 mph possible. In addition, Pacific moisture will promote orographic rain showers along the Continental Divide including areas in Glacier National Park. Temperatures will be cooler on Sunday and Monday, however will remain around seasonal averages. MLV Monday night through Saturday...The main weather feature to contend with is the development of a strong upper trough over the west coast by early Wednesday and its subsequent movement. Models are in pretty good agreement through Wednesday as an upper low develops in the vicinity of southwest Idaho by late Wednesday afternoon. After that model differences come into play. The main difference is that the ECMWF model is slower than the other models with the northern portion of the upper trough and its associated precipitation. The GEM and ECMWF develop more of an upslope flow than the GFS which is weaker with the upper low/trough. Since the GFS can be too quick in weakening weather systems will lean towards a wetter solution than what the GFS would indicate. Have increased the chances of precipitation for Tuesday night into Thursday. As was mentioned in yesterdays discussion it still looks like snow levels will lower to between 5500 and 6500 on Wednesday but could further lower to between 4500 and 5500 feet Wednesday night. As was also mentioned in yesterdays discussion still could see snowfall totals of 6 to 12 inches over the southwest and central mountains. Although have highs only in the mid 40s to mid 50s Wednesday and Thursday coldest guidance would have highs only in the 40s. Precipitation chances diminish and daytime temperatures warm later in the week as an upper ridge is expected to develop over Montana. Blank && .AVIATION... UPDATED 2345Z. Upper level shortwave trough and associated surface cold front will push through the forecast area overnight. Main impact of this system will be increasing mid- and high-level clouds through the evening hours. After 06Z a line of showers is expected to develop from near KCTB southwestward across the continental divide to KMSO. This line is expected to remain quasi-stationary through 18Z with mountain obscurations and MVFR/IFR conditions in mountain snow and low elevation rain. After 18Z, isolated to scattered showers will spread southeast over the Central and Southwest Montana mountains. mpj && .PRELIMINARY POINT TEMPS/POPS... GTF 49 69 46 67 / 30 30 10 10 CTB 44 67 41 61 / 20 20 10 10 HLN 50 68 45 66 / 30 50 10 10 BZN 45 69 41 67 / 20 40 20 10 WEY 36 57 31 55 / 30 50 30 10 DLN 44 62 38 62 / 30 50 10 10 HVR 48 73 44 69 / 20 10 10 10 LWT 47 67 42 64 / 20 30 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES... HIGH WIND WATCH from Sunday evening through Monday evening Northern Rocky Mountain Front...Southern Rocky Mountain Front. && weather.gov/greatfalls
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 300 PM MDT SAT SEP 21 2013 MTZ009-048-222100- NORTHERN ROCKY MOUNTAIN FRONT-SOUTHERN ROCKY MOUNTAIN FRONT- 300 PM MDT SAT SEP 21 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT THERE IS A LOW PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY A HIGH WIND WATCH IS IN EFFECT FROM SUNDAY EVENING THROUGH MONDAY EVENING FOR THE ROCKY MOUNTAIN FRONT. A STRONG PACIFIC STORM SYSTEM IS EXPECTED TO MOVE INTO THE WESTERN U.S. LATE TUESDAY AND SLOWLY TRACK EAST ACROSS THE REGION TUESDAY NIGHT THROUGH THURSDAY. WHILE THERE IS STILL A LARGE AMOUNT OF UNCERTAINTY IN THE TIMING AND INTENSITY OF THIS SYSTEM...THERE IS GROWING CONFIDENCE THAT WIDESPREAD PRECIPITATION...HEAVY MOUNTAIN SNOW AND MUCH COOLER TEMPERATURES WILL IMPACT THE REGION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MTZ008-010>015-044>047-049>055-222100- BEAVERHEAD-EASTERN GLACIER-HILL-CASCADE-CHOUTEAU- CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-TOOLE-LIBERTY- EASTERN PONDERA-BLAINE-EASTERN TETON-JUDITH BASIN-FERGUS- JEFFERSON-BROADWATER-MEAGHER-GALLATIN- 300 PM MDT SAT SEP 21 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY GUSTY WEST WINDS ARE EXPECTED SUNDAY NIGHT AND MONDAY ACROSS CENTRAL MONTANA. A STRONG PACIFIC STORM SYSTEM IS EXPECTED TO MOVE INTO THE WESTERN U.S. LATE TUESDAY AND SLOWLY TRACK EAST ACROSS THE REGION TUESDAY NIGHT THROUGH THURSDAY. WHILE THERE IS STILL A LARGE AMOUNT OF UNCERTAINTY IN THE TIMING AND INTENSITY OF THIS SYSTEM...THERE IS GROWING CONFIDENCE THAT WIDESPREAD PRECIPITATION...HEAVY MOUNTAIN SNOW AND MUCH COOLER TEMPERATURES WILL IMPACT THE REGION. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
3 high wind. Local standard time, as filed.
High winds measuring 54KT (63MPH) reported at the Logan Pass Visitors Center.
Sustained high winds peaked at a measured 69KT (79MPH) at the Logan Pass Visitors Center.
High winds measuring 50KT (58MPH) reported at the Deep Creek RAWS.
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: 475747, 475748, 475746.