Northwesterly flow aloft behind a departing shortwave trough quickly became westerly and strengthened along the Northern Rocky Mountain Front, bringing windy conditions to the region.
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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.
Northwesterly flow aloft behind a departing shortwave trough quickly became westerly and strengthened along the Northern Rocky Mountain Front, bringing windy conditions to the region.
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 Dec 26, 10:48 AM MST, 1 hour 5 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 1048 AM MST Mon Dec 26 2022 ...Morning Update and Aviation Section Update... .SYNOPSIS... An unsettled weather pattern continues for the remainder of the week, with a parade of Pacific weather systems bringing periods of strong gusty winds and mostly mountain snow. The strongest system will move into the Northern Rockies Tuesday into Wednesday, when accumulating snow and strong winds will impact locations along the Continental Divide and the higher terrain along the Idaho and Wyoming borders. Temperatures will initially run above average, but will trend closer to normal toward the weekend. && .UPDATE... We have increased PoPs and QPF a bit for the next few hours as a warm front is generating some brief freezing rain over eastern parts of north-central Montana. As the warm front crosses the area and helps to mix down warmer air aloft, the temperature has risen from the lower teens above zero to around 40 degrees in the Havre area in the last hour or so, with some light freezing rain also occurring. The other significant change was to upgrade the Winter Storm Watch to a Winter Storm Warning for the public zones bordering northeastern Idaho and northwestern Wyoming. The Winter Storm Warning is being issued more for the high wind component than for the heavy snow component, though the West Yellowstone area will likely come close to meeting the snow accumulation criteria. Nevertheless, the primary impact with the Winter Storm Warning will be the significant blowing and drifting snow component, especially outside of the West Yellowstone. For the afternoon forecast package, there will be consideration for needing a Winter Weather Advisory for northeastern parts of the forecast area Tuesday as a warm front lifts northeast across the area with overrunning rain developing and falling on surfaces that are at or below freezing. This is a reminder that while road temperatures may briefly rise above freezing given the warmer ambient temperatures, sub-surface temperatures remain far below freezing and will cause roads to refreeze with the loss of minimal daytime heating. There are no other significant changes to the current watches, warnings, and advisories. && .AVIATION... 1045 AM MST Mon Dec 26 2022 (26/18Z TAF period) Freezing rain transitioning over to rain ahead of a warm front across the High Plains region should diminish between 18z and 20z for KHVR. Surface winds strengthen and become gusty this afternoon that will last through the overnight period. Low level wind shear has high probability of occurring across all terminals through portions of the TAF period. Another weather system moves in tonight along the Rocky Mountain Front, bringing mountain rain and snow showers. Mountain obscuration is expected for the TAF period and CIGs will begin to fall again after 27/06Z as snow and rain move across Southwest Montana and portions of Central Montana. Visibility has potential to be periodically reduced tomorrow morning into the afternoon. Webb Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information && .HYDROLOGY... A Flood Advisory remains in effect for the Gallatin River at Logan as minor flooding continues due to an ice jam. River levels remain stable at just above minor flood; however, given the unpredictable nature of ice jams and resultant flooding those with interest along the river should remain vigilant and be prepared to act should floodwaters rise further. && .PREV DISCUSSION... /ISSUED 503 AM MST Mon Dec 26 2022/ Today through Tuesday night...Northwesterly flow aloft behind the departing shortwave trough will quickly become westerly and strengthen today, bringing more windy conditions and mild temperatures. Before this occurs, very cold, moist surfaces will continue to create slippery roads/sidewalks through the morning hours. Patchy fog has also developed along the Milk River Valley and some southwest valleys, which may persist through mid- morning. Yesterday's front has brought cold air back into the Milk River valley, which introduces concern on whether these areas will be able to achieve their forecast highs. The rather strong westerly flow aloft should be enough warm these areas by this afternoon, but I did lower maximum temperatures down a few degrees to the mid- and upper 30s in anticipation of models bringing in warmer air a few hours too early. As mentioned earlier, it will be on the windier side today and the strongest winds through this evening are still forecast to be along the Rocky Mountain Front, the plains, and the north/south oriented southwest valleys. The latest NBM 4.1 wind gust exceedence probabilities for magnitudes of 55 mph or higher remain at 50 percent or higher along the Rocky Mountain Front, but are running at around 30 percent or less for other areas. A High Wind Warning was issued for the Northern Rocky Mountain Front zones 301 and 302 this afternoon through late tonight due a 50 + percent chance for gusts over 74 mph. In addition to that, the probability for sustained winds of 39 mph or greater are also running above 50 percent. Mostly dry conditions are expected for today, though periods of light snow will be possible along the Divide and the far southwestern mountains. A broad H500 trough will impact the Northern Rockies late Monday night through Wednesday and bring a round of accumulating snow to the Divide and over the southwest mountains along the ID/WY borders. Winds also become strong over the southwest, especially in the Madison Valley. Snowfall amounts aren't overly impressive, but a snowfall of in excess of 6 inches is expected over the Centennial Mountains and in the west Yellowstone area. Also, blowing snow may create hazardous driving conditions in the Monida Pass area. H700 winds look to exceed 50 kts and the EC Extreme Forecast Index indicates a weak signal for anomalous surface winds. Given these factors, I decided to issues a Winter Storm Watch for public zones 329 and 330 from midnight tonight through 8 am Wednesday morning. The inherited High Wind Watch for the Madison Valley was upgraded to a High Wind Warning and the start times was shifted 6 hours earlier to midnight tonight. The remainder of the High Wind Watch will continue as is, but its effective time was moved up to match the Madison Valley warning. Snowfall and winds will peak in coverage and intensity Tuesday afternoon and night, but windy conditions and lingering snows may persist through the day on Wednesday and possibly beyond. Precipitation will be much spottier for lower elevations Tuesday into Wednesday and shouldn't be very impactful. The one potential exception to this will be in the Milk River Valley, where a few hundredths of rain could fall over very cold surfaces. Even though air temperatures are generally progged to be above freezing, I did add the mention of light freezing rain and light accumulating ice to the grids. No winter weather products were issued for this, but the situation will continue to be monitored. -RCG Wednesday through Wednesday night...H500 shortwave will continue to slide east and over the Northern Rockies through the day on Wednesday, with northwesterly flow developing over Southwest through North Central Montana during the overnight hours as transient ridging begins to build in over the Pacific Northwest. This will lead to continued snow, albeit light accumulations of 1-2", along the Continental Divide and across the mountains of Southwest Montana for much of the period. Snow will begin to wind down in areal coverage during the evening and overnight hours on Wednesday. In addition to the snow, gusty southwest to west surface winds are expected across much of the CWA, particularly along the Rocky Mountain Front. NBM4.1 probabilistic guidance suggests a high (greater than 70%) chance that wind gusts exceed 55 mph for areas along and west of the US Hwy 89 corridor along the Rocky Mountain Front, with a moderate (40-70%) chance that wind gusts exceed 65 mph. Given the anticipated new snowfall, particularly across the East Glacier Park Region, future winter weather highlights may be need to address the blowing/drifting snow that will likely develop. At this time no High Wind highlights are anticipated as wind gusts are expected to remain below the 75 mph threshold for these Rocky Mountain Front zones. Thursday through next Sunday...a progressive pattern will bring near normal (with the exception of above normal lows Thursday and Friday night's in downsloping areas over the plains of Central and North Central Montana) temperatures and mountain snow to areas along the Continental Divide and across Southwest Montana throughout much of the period. - Moldan && .PRELIMINARY POINT TEMPS/POPS... GTF 46 36 47 33 / 40 10 40 0 CTB 43 30 40 28 / 30 20 40 10 HLN 45 33 46 29 / 20 10 60 20 BZN 40 28 42 23 / 30 10 60 20 WYS 35 23 36 18 / 50 10 100 90 DLN 40 31 41 21 / 20 10 60 30 HVR 41 30 40 28 / 50 10 60 10 LWT 45 34 46 28 / 40 10 40 10 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 2 AM MST Tuesday for East Glacier Park Region-Northern High Plains. Winter Storm Warning from midnight tonight to midnight MST Tuesday night for Gallatin and Madison County Mountains and Centennial Mountains-Ruby Mountains and Southern Beaverhead Mountains. High Wind Warning from midnight tonight to 11 PM MST Tuesday for Madison River Valley. A Flood Advisory for the Gallatin River at Logan is effect until Wednesday at 10 AM. && http://www.weather.gov/greatfalls
Special Weather Statement National Weather Service Great Falls MT 651 AM MST Mon Dec 26 2022 MTZ301>330-261900- East Glacier Park Region-Northern High Plains- Eastern Glacier, Western Toole, and Central Pondera- 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- Cascade County below 5000ft-Judith Basin County and Judith Gap- Fergus County below 4500ft-Upper Blackfoot and MacDonald Pass- Gates of the Mountains-Little Belt and Highwood Mountains- Snowy and Judith Mountains-Helena Valley- Big Belt, Bridger and Castle Mountains-Meagher County Valleys- Elkhorn and Boulder Mountains-Canyon Ferry Area- Missouri Headwaters-Madison River Valley-Gallatin Valley- Northwest Beaverhead County- Beaverhead and Western Madison below 6000ft- Ruby Mountains and Southern Beaverhead Mountains- Gallatin and Madison County Mountains and Centennial Mountains- Including the cities of East Glacier Park, Kiowa, Babb, Saint Mary, Marias Pass, Logan Pass, Browning, Heart Butte, Dupuyer, Cut Bank, Ethridge, Santa Rita, 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, Rocky Boy, Great Falls, Raynesford, Geyser, Stanford, Windham, Benchland, Hobson, Moccasin, Hilger, Lewistown, Marysville, Lincoln, Flesher Pass, MacDonald Pass, Canyon Creek, Wolf Creek, Craig, Monarch, Neihart, Kings Hill Pass, Helena, Trident, Maudlow, Battle Ridge Pass, Bozeman Pass, Deep Creek Pass, Martinsdale, Checkerboard, Ringling, White Sulphur Springs, Montana City, Clancy, Boulder, Corbin, Wickes, Elk Park Pass, Homestake Pass, Toston, Townsend, Winston, Harrison, Three Forks, Willow Creek, Pony, Whitehall, Cameron, Ennis, Jeffers, McAllister, Norris, Bozeman, Gallatin Gateway, Dewey, Wisdom, Wise River, Big Hole Pass, Chief Joseph Pass, Bannack, Dillon, Glen, Waterloo, Monida Pass, Big Sky, West Yellowstone, Targhee Pass, and Raynolds Pass 651 AM MST Mon Dec 26 2022 ...Areas of black ice and frost on roads this morning... Caution is advised for all travelers as black ice and frost on roads are creating slick conditions across much of north-central and southwest Montana this morning. This is due to the combination of recent warmer air temperatures while road and ground surfaces remain at or below freezing. Assume any roads that appear wet or with frost on them to be icy, as subsurface road temperatures are still well below freezing across the region and will remain that way for the next several days.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
Mesonet station MTBRN Two Medicine Bridge measured a gust of 79 mph. The sensor also measured a 75 mph gust. Otherwise, no other sensors measured gusts of 75 mph or greater in this zone.
ASOS station KCTB Cut Bank Airport measured two 62 mph gusts in quick succession.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2022Every state in 2022This day in weather historyWarnings in Montana, December 2022
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: 1071645, 1071646.