Mid level westerly flow increased once again, resulting in strong lee side troughing and resulting winds along the Rocky Mountain Front and adjacent plains.
Every event with a place to put it; 12 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
Mid level westerly flow increased once again, resulting in strong lee side troughing and resulting winds 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 Feb 12, 10:10 AM MST, 28 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 1010 AM MST Sun Feb 12 2023 ...AVIATION SECTION UPDATE... .SYNOPSIS... While weather across Southwestern Montana will remain quiet today, winds will be on the increase across the North-Central Plains as a weather disturbance approaches from the west. Winds will peak overnight Sunday night into Monday morning across the plains, with some snow expected to begin across Southwestern Montana Monday afternoon and evening. && .UPDATE... The morning update has been published. The primary change was to begin the High Wind Warning for the Rocky Mountain Front and eastern Glacier County immediately. Winds are already gusting up to and in excess of 55 mph along the immediate eastern slopes of the Rocky Mountain Front, with further increase expected later this morning and afternoon. The period of strongest winds is still expected this evening through Monday morning. Only minor changes were made to the remainder of the forecast per current trends. -RCG && .AVIATION... 1005 AM MST Sun Feb 12 2023 (12/18Z TAF Period) Strong low level and sfc winds to be primary aviation weather impact for this TAF period. Mountain wave expected to impact areas along and adjacent to the eastern Rocky Mountain Front primarily after dark tonight and into early Mon morning. Strongest winds expected to occur at KCTB and vcnty with sustained values of 30 to 40 kts likely and gusts in excess of 50 kts at times. Elsewhere, sfc winds will generally strengthen this afternoon and especially tonight. Wind speeds should peak tonight and only slowly weaken during the day Monday. Otherwise, VFR will prevail this afternoon with thickening CI at times. Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .PREV DISCUSSION... /ISSUED 237 AM MST Sun Feb 12 2023/ Today through Monday...primary forecast concern throughout the period will be the threat for High Winds from late this afternoon through Monday afternoon, and accumulating snow across all elevations along the Continental Divide and across Southwest and portions of Central Montana, mainly along and south of the Montana Hwy 200 corridor, from Monday afternoon through early Tuesday morning. H500 ridge over the Pacific Northwest and western portions of the Northern Rockies this morning will be flattened out by a potent H500 shortwave, currently over the Gulf of Alaska, which will dig to the southeast over British Columbia and the Pacific Northwest by Monday morning and then the Great Basin through Tuesday morning. At the surface, lee-side surface trough will begin to sharpen rapidly this afternoon and through Monday morning across the plains of Central and North Central Montana as a strong (~980-985mb) surface low moves from the Gulf of Alaska (this afternoon) across Northern Alberta (near midnight tonight) to Northern Saskatchewan (Monday afternoon). Surface pressure gradient along the Rocky Mountain Front, while strong already this morning, will become very strong at around 17.5- 22.5mb/km by the evening hours tonight and persist into the morning hours on Monday. This very strong surface pressure gradient combined with increasing cross barrier flow of 50-70kts (between H850-700) and a strengthening inversion near ridgetops along the Rocky Mountain Front will set the stage for very strong west winds from the late afternoon through Monday afternoon, especially beneath mountain wave activity. At this time it appears that the most intense winds will occur from ~04z this evening through 16z Monday along and west of the US Hwy 89 corridor across the Blackfeet Nation. NBM probabilistic data suggests a 60-90% chance that wind gusts will exceed 64kts across the aforementioned region of the Blackfeet Nation, with Hi-Res and NBM deterministic guidance suggesting several mountain waves developing and propagating eastward across Glacier County. Would not be surprised if the Browning area sees several periods of sustained winds of 50-60mph, with gusts approaching 90 mph, this evening and Monday morning. A High Wind Warning remains in effect from 00z Monday through 22z Monday for the Northern and Southern High Plains adjacent to the Rocky Mountain Front, and Eastern Glacier/Western Toole/Central Pondera Counties. Considered adding the Southern Rocky Mountain Front and Eastern Glacier Park Region to the High Wind Warning as the wind orientation appears favorable for the Gleason and St Mary RAWS to hit high wind criteria, but decided to hold-off for now given these areas stubbornness to "verify". Focus then shifts to the precipitation/winter side of the approaching shortwave. Increasing ascent and intense H500 height falls of ~130m to ~180m will begin to overspread Southwest through North Central Montana from Monday morning through Monday night, which combined with a plume of Pacific moisture advecting east ahead of an eastward advancing Pacific cold front will lead to the development of precipitation (i.e. snow) along the Continental Divide and across Southwest and portions of Central Montana (mainly along and south of the Montana Hwy 200 corridor). Snowfall accumulations of generally 1-3" remain possible across the aforementioned lower elevations over this timeframe, with 3-6" of snow at pass level and around 6-12" in the mountains of Glacier National Park and the Gallatin and Madison Counties. A brief period of moderate to heavy snow could develop along and immediately behind the eastward advancing Pacific cold front Monday evening/night, mainly along and south of the US Hwy 12 corridor across Central Montana. This brief period of heavier snow could lead to significant visibility reductions, especially along the busy I-90 corridor from Bozeman to Butte. - Moldan Tuesday through next weekend... Winds will begin to decrease rather quickly after sunrise Tuesday as the axis of the upper level trough begins to push east and a high pressure system begins to slide southward out of Canada. As this high pressure system pushes to the south, some upslope snow is expected along the eastern slopes of the Rocky Mountain Front and on the northern slopes of the Little Belt and Snowy Mountains. Snow will continue to fall across Southwestern Montana as well on Tuesday from a combination of the upper level trough and the cold front that will be surging southward through the area. One thing to keep an eye on across Southwestern Montana will be the possibility for a brief period of gusty winds as colder air surges through some of the North-South oriented valleys. After an active weather day on Tuesday, the rest of the work week will be relatively quiet as upper level ridging builds into the Northwestern US. As this ridge builds in, expect temperatures to warm a few degrees each day, though some of the valleys could be slow to warm up thanks to some valley inversions. These warmer temperatures across the plains will be accompanied by some occasionally breezy winds, but expect dry conditions to close out the work week. As we head into the weekend, another upper level trough may push through the area, but uncertainty remains as to where this system may track and how strong/widespread any winds or precipitation would be. Ludwig && .PRELIMINARY POINT TEMPS/POPS... GTF 50 42 51 27 / 0 0 20 40 CTB 48 40 49 23 / 0 0 10 30 HLN 44 28 45 25 / 0 10 40 70 BZN 37 18 40 17 / 0 0 40 100 WYS 37 4 35 7 / 0 0 30 100 DLN 35 18 37 17 / 0 0 40 90 HVR 41 33 45 20 / 0 0 10 20 LWT 47 32 47 23 / 0 0 30 70 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 3 PM MST Monday for Eastern Glacier, Western Toole, and Central Pondera-Northern High Plains-Southern High Plains. Winter Storm Watch from Monday afternoon through Tuesday evening for Big Belt, Bridger and Castle Mountains-East Glacier Park Region-Elkhorn and Boulder Mountains-Gallatin and Madison County Mountains and Centennial Mountains-Gates of the Mountains-Little Belt and Highwood Mountains-Snowy and Judith Mountains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass. && http://www.weather.gov/greatfalls
The national radar mosaic for the moment the first event began.
12 high wind. Local standard time, as filed.
Mesonet station MTBRN Two Medicine Bridge measured a lone gust of 60 mph. Additionally, sustained winds of 41 mph averaged over an hour occurred.
Ambient Weather sensor at LJ Johnson Farms measured a two gusts in excess of 58 mph, including a 79 mph gust.
Mesonet station DELMT Dellwo measured multiple gusts in excess of 58 mph, including a peak gust of 65 mph. This site also had sustained winds averaging 40 mph or greater over a few hours over the specified timeframe.
Mesonet station MTBWG measured multiple gusts in excess of 58 mpg, including a peak wind gust of 66 mph. Sustained winds of 52 mph, averaged over an hour, were also observed.
The Lewis and Clark Portable RAWS TR276 measured multiple gusts in excess of 58 mph, including a peak gust of 70 mph.
Mesonet station KMTBYNUM11 measured multiple gusts of 58 mph or greater, including a peak wind gust of 60 mph. Due to uncertainty as to when the high winds started, the end time of the event is used as both the start and finish time for this event.
Mesonet station SHBM Browning measured multiple wind gusts of 58 mph or greater, including a peak gust of 60 mph.
ASOS KCTB Cut Bank Airport measured multiple gusts of 58 mph or greater, including a peak wind gust of 63 mph.
An Ambient Weather sensor in Cut Bank measured two gusts in excess of 58 mph, including a peak gust of 63 mph.
ASOS Station KGTF Great Falls Airport measured a gust of 58 mph.
Mesonet station KMTAUGUS11 measured a gust of 62 mph.
Ambient Weather sensor at Bartsch Farms measured a gust of 59 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: 1073945, 1071900, 1073951, 1073946, 1071901, 1073952, 1073947, 1073948, 1073949, 1071819, 1073950, 1071903.