An upper trough breaking down a ridge brought strong zonal flow to the region. Weak ridgetop stability resulted in strong winds along the immediate eastern slopes and out to the Cut Bank area for a brief period Sunday the 19th.
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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.
An upper trough breaking down a ridge brought strong zonal flow to the region. Weak ridgetop stability resulted in strong winds along the immediate eastern slopes and out to the Cut Bank area for a brief period Sunday the 19th.
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 Feb 19, 5:38 AM MST, 1 hour 37 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 538 AM MST Sun Feb 19 2023 ...AVIATION SECTION UPDATED AND TFX WATCHES/WARNINGS/ADVISORIES SECTION CORRECTED... .SYNOPSIS... Gusty westerly winds develop over much of North-Central Montana today, strongest along the Rocky Mountain Front. Snow will mostly be confined to higher the higher terrain, but scattered lower elevation snow showers will be present. Then a slow moving storm system and attendant Arctic boundary shifts the Northern Rockies into an snowier and much cold weather pattern next week. && .DISCUSSION... An increasingly moist and unsettled northwesterly flow aloft persists over the Northern Rockies through Monday afternoon before broad Pacific trough and attendant Arctic boundary dives southward into the region Monday night into Tuesday. Primary concerns for this period will be gusty, and strong at times, westerly winds over Rocky Mountain Front/the plains and mountain accumulating snow. Lee side troughing combined with H700 50 kt flow looks to be just enough to support winds guts exceeding 55 mph for the Rocky Mountain Front through this evening, while most plains locations see gusts generally fall in the 30 to 50 mph range. Given the high probabilities (> 80%) for wind gusts exceeding 55 mph along the Rocky Mountain Front and immediate adjoining plains, the inherited High Wind Warning for these areas will be left as is to go in effect from 9 am to 9 pm MST today. Passing weak disturbances and Pacific moisture aloft will bring periods of mountain snow and lower elevation snow showers today and Monday, with the heaviest snowfall accumulations expected in the Marias Pass area and the Little Belt Mountains. The Winter Weather Advisory for the Rocky Mountain Front was upgraded to a Winter Storm Warning, while the Big Belt and Gallatin/Madison Ranges zones were left as Winter Weather Advisories. The combination of increasing Pacific moisture streaming over a southward weak surface cold front will increase the potential for more widespread, but wet, snowfall over the plains during the day on Monday. I felt that this variety of snowfall was too light to include with the bigger event, so a Winter Weather Advisory was issued for areas roughly southwest of a Shelby to Winifred line. A couple inches of wet accumulation are likely (> 70%) for these areas. Monday night through early Wednesday is still expected to be the most active period of the week, with the slow moving mid- level trough and Arctic boundary exerting its greatest influence over the Northern Rockies. The timing for the arrival of the Arctic air has been trending a little later with the latest guidance. Now it appears the cold front will pass through the plains late Monday night into Tuesday morning and then the southwest later Tuesday afternoon and evening. The most impactful snowfall will occur along and just north of this boundary. Snowfall amounts have dropped a bi for the Helena/Canyon Ferry and the Dillon areas, but these areas will still need to be monitored for gusty northerly winds Tuesday night into early Wednesday as H700 flow gets funneled through north/south oriented valleys behind the front. Wind exceedence probabilities for gusts over 55 mph are running well above 50% for these areas and this is supported by the ECMWF EFI/shift of tails index, which indicates a signal for anomalously strong winds. Areas further north will have wind/blowing snow concerns along and behind the front as suggested by the same indices. Northern areas most impacted by winds will be the eastern foothills along the Continental Divide and the Judith Gap area. Seventy-two hour snowfall exceedence probabilities haven't changed much outside of the aforementioned southwestern locations, still looking at most central/north- central lower elevations having a 60 % + chance of 6 inches or more of snow and a 70% + chance for 12 inches or more over higher terrain. The higher terrain along the Rocky Mountain Front and over the Little Belts have over a 50 % chance of exceeding 18 inches. The snow with this system will begin to wind down Wednesday morning, though lighter snows may persist through Wednesday afternoon. The most significant change to the winter weather highlights was to convert most of the mountain Winter Weather Advisories for later today into Winter Storm Warnings that run through the duration of this winter storm event. Also, a Winter Weather Advisory was issued for portions of North-Central Montana for the 5 PM to 5 PM timeframe on Monday before the Winter Storm Watch goes into effect Monday evening. Otherwise, the Little Belts were taken out of this morning's early Winter Weather Advisory, with the Gallatin/Madison Ranges retaining in it through 5 am. The cold will be the second significant impact from this system, with both daytime and nighttime temperatures plunging near or below zero Tuesday through early Friday. The coldest days will be Wednesday and Thursday, when most central/north-central locations have an 70% + chance for highs staying below zero. Probabilities for southwestern areas aren't as robust, but sometimes model guidance displays a warm bias in these situations. Regardless, wind chills in the -15F to -35F range will be common during this period, likely resulting in some wind chill highlights further down the line. By Friday afternoon the Arctic chill begins to loosen its grip on the Northern Rockies, though a cold northwesterly flow aloft will be maintained through at least next Saturday. Expect areas along the Hi- line and the southwestern valleys to 'retain' their colder air the longest. Winds will begin to increase along the Rocky Mountain Front and plains, particularly on Saturday. Blowing snow could become impactful, depending on how much snow falls with the prior storm and how fast temperatures can warm up. -RCG && .AVIATION... 538 AM MST Sun Feb 19 2023 (19/12Z TAF Period) Subtle disturbances within an unsettled northwesterly flow aloft will maintain scattered snow showers for much of the period, most numerous late this afternoon into tonight. Mostly VFR conditions are initially expected, but MVFR and even IFR will become more common after 20/00Z, especially for KLWT. Gusty westerly surface winds will develop by this afternoon, strongest along the Rocky Mountain Front and the plains. Northwesterly H700 flow as high as 50 kts will increase mountain wave activity and instances of low level wind shear, mostly along the continental Divide. -RCG Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PRELIMINARY POINT TEMPS/POPS... GTF 43 31 37 26 / 30 70 80 90 CTB 42 27 32 13 / 10 80 60 90 HLN 40 33 42 28 / 40 50 60 80 BZN 34 25 39 26 / 50 60 70 80 WYS 23 11 31 16 / 80 90 90 90 DLN 33 27 40 29 / 10 20 20 40 HVR 39 24 32 13 / 20 40 30 90 LWT 37 27 32 22 / 30 80 90 100 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 9 AM this morning to 9 PM MST this evening for Eastern Glacier, Western Toole, and Central Pondera- Northern High Plains-Southern High Plains. Winter Storm Warning from 11 AM this morning to 11 PM MST Wednesday for Big Belt, Bridger and Castle Mountains-East Glacier Park Region-Gallatin and Madison County Mountains and Centennial Mountains-Little Belt and Highwood Mountains-Snowy and Judith Mountains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass. Winter Weather Advisory from 5 AM to 5 PM MST Monday for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft- Eastern Glacier, Western Toole, and Central Pondera-Eastern Pondera and Eastern Teton-Fergus County below 4500ft-Judith Basin County and Judith Gap-Northern High Plains-Southern High Plains. Winter Storm Watch from Monday afternoon through late Tuesday night for Bears Paw Mountains and Southern Blaine-Cascade County below 5000ft-Eastern Glacier, Western Toole, and Central Pondera- Eastern Pondera and Eastern Teton-Eastern Toole and Liberty- Fergus County below 4500ft-Gates of the Mountains-Hill County- Judith Basin County and Judith Gap-Meagher County Valleys- Northern Blaine County-Northern High Plains-Southern High Plains- Western and Central Chouteau County. Winter Storm Watch from late Monday night through late Tuesday night for Elkhorn and Boulder Mountains-Gallatin Valley- Northwest Beaverhead County-Ruby Mountains and Southern Beaverhead Mountains. && http://www.weather.gov/greatfalls
The national radar mosaic for the moment the first event began.
5 high wind. Local standard time, as filed.
Mesonet station DELMT Dellwo measured two gusts in excess of 58 mph, including a peak gust of 61 mph.
The Lewis and Clark Portable RAWS TR276 measured multiple gusts in excess of 58 mph, including a 72 mph gust.
Ambient Weather sensor at LJ Johnson Farms measured a wind gust of 74 mph.
Mesonet station MTBWG Browning DOT had sustained winds averaging 40 mph for an hour-long period.
ASOS station KCTB Cut Bank Airport measured sustained winds, averaged over an hour, of 40 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2023Every state in 2023This day in weather historyWarnings in Montana, February 2023
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: 1073966, 1071920, 1071919, 1071917, 1073965.