Strong Mid level flow mixed to the surface near to the Rocky Mountain Front and adjacent plains and in the Madison River Valley in Southwest Montana. Otherwise, most other locations stayed below high wind criteria.
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.
Strong Mid level flow mixed to the surface near to the Rocky Mountain Front and adjacent plains and in the Madison River Valley in Southwest Montana. Otherwise, most other locations stayed below high wind criteria.
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 Apr 9, 10:45 PM MST, 1 hour 22 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 1145 PM MDT Sun Apr 9 2023 Updated Aviation Discussion .SYNOPSIS... High pressure builds across the area through Monday for dry conditions with increasingly above-normal temperatures. Gusty winds persist through Tuesday for much of north-central Montana with strong winds likely tonight along the northern Rocky Mountain Front. Windy conditions are likely Tuesday ahead of a cold front moving in from the northwest with high winds possible especially across southwest Montana Tuesday afternoon, but possibly extending across much of north-central and central Montana as well. Cooler and unsettled conditions develop mid to late this week. && .UPDATE... No significant update was necessary this evening. Latest high resolution guidance continues to support the arrival of strong winds along the Northern Rocky Mountain Front overnight. Hence, the going High Wind Warning there is in good shape. Given continued reports of water covering roadways in the vicinity of the Bears Paw Mountains, the Flood Advisory for the area has been extended until 6 PM tomorrow. No other changes to products were made at this time. -AM && .AVIATION... 1145 PM MDT Sun Apr 9 2023 (10/06Z TAF Period) VFR conditions prevail through Monday night beneath an upper level ridge across the Northern Rockies and MT with variable amounts of mainly high level clouds streaming across the area. South to southwesterly surface winds persist at most terminals with gusty winds continuing tonight across western portions of north-central MT. Strong winds are expected along the immediate east slopes of the Rocky Mtn Front through Monday morning with potential for gusts to around 40kts reaching as far east as KCTB at times overnight. Most locations will see 20-35kt gusts Monday afternoon with atmospheric mixing. Stronger SW flow aloft develops across the region Tuesday with some areas of low-level wind shear possible across mainly SW MT by early Tuesday morning. Hoenisch Refer to weather.gov/zlc for more detailed regional aviation weather and hazard information. && .HYDROLOGY... An analysis of Modeled Snowpack Temperatures from the National Operational Hydrologic Remote Sensing Center (nohrsc.noaa.gov) at 8 am this morning shows a substantial warming of the existing snowpack over the Bears Paw Mountains and extending all the way to the Canadian border compared to the same time yesterday. Given the warm daytime and overnight temperatures expected for the next 48 hours, we expect most of this snowpack to melt out and cause at least minor flooding issues on the tributaries of the Milk River, as well as lowland flooding where water collects and drainage is poor. A Flood Watch continues through Wednesday for Liberty, Hill, Blaine and Chouteau counties where additional impacts to roads and rural areas are likely to develop. A Flood Advisory continues today for areas near the Milk River Valley and Bears Paw where minor flooding is already occurring and affecting several roads. A Flood Watch goes into effect this afternoon for the Gallatin Valley, where a substantial snow-pack still exists and warmer temperatures today will bring accelerated melting and potential for minor flooding, especially to low-lying and poorly drained areas. CC/Hoenisch && .PREV DISCUSSION... /ISSUED 521 PM MDT Sun Apr 9 2023/ Based on latest HREF ensemble max wind gust guidance, we have extended the High Wind Warning for the East Glacier and Northern Rocky Mountain Front zones from 6 AM to 9 AM Monday, where wind gusts to 85 mph are expected. The upper-level ridge bringing above normal temperatures to the region resides across central Montana, and will continue to build east and northeast over the next couple of days. This ridge breaks down Monday night into Tuesday, with a strong southwesterly jet stream aloft impacting the region Monday through Thursday. While on the warm side of the jet streak Monday into Tuesday, very warm maximum and minimum temperatures can be expected along with breezy to windy conditions. As the jet axis slides east in tandem with a passing cold front Tuesday, temperatures will fall to below normal with rounds of mountain snow and a mix of rain and snow at lower elevations for the Wednesday-Friday time period. We have expanded the High Wind Watch for Tuesday to include parts of north-central and central Montana as the jet streak and cold front move across the area from west to east. Deterministic model guidance and a long-used and reliable rule of thumb suggests widespread high winds Tuesday in association with a powerful jet stream and strong cold front passage. However, where NBM probabilities are lower across some parts of north-central Montana we have decided to show some hesitancy given we're still over 36 hours away from onset of this wind event. By late this evening, the HREF which covers a 48-hr period will cover the Tuesday afternoon period and allow us higher confidence in the extent of high sustained winds and wind gust possibilities across the forecast area. NBM sustained wind and wind gusts probabilities for reaching or exceeding High Wind Warning criteria remain quite high (>80%) over much of southwest Montana, including areas that typically do not see high winds such as the Gallatin Valley, and an upgrade to a High Wind Warning seems likely sooner than later. The previously mentioned cold front continues to sag SE across the area Tuesday night as the upper trough advances further into the NW US. Precipitation chances increase Tuesday night and Wednesday with temperatures falling back below seasonal averages. Daytime temperatures in the 40s are likely Wednesday and Thursday, about 30 degrees colder than the mild conditions earlier this week. There is still a fair amount of uncertainty with precipitation amounts and timing after Wednesday, though most model guidance would bring a round of more widespread precipitation to the area in the Thu/Fri period as the upper trough axis moves through the region. This would likely be in the form of snow with latest statistical guidance giving a better than 50% probability of 2" or greater snowfall to the mountains of central/SW MT with 20-40% probabilities for similar snow amounts at lower elevations. CC/Hoenisch && .PRELIMINARY POINT TEMPS/POPS... GTF 51 75 54 65 / 0 0 0 20 CTB 46 71 46 53 / 0 10 0 20 HLN 43 74 48 66 / 0 0 0 40 BZN 36 68 43 65 / 0 0 0 10 WYS 31 59 36 56 / 0 0 0 10 DLN 37 61 43 60 / 0 0 0 20 HVR 44 66 49 60 / 0 10 0 10 LWT 46 71 52 69 / 0 0 0 20 && .TFX WATCHES/WARNINGS/ADVISORIES... Flood Watch through Wednesday morning for Bears Paw Mountains and Southern Blaine-Eastern Toole and Liberty-Gallatin Valley- Hill County-Northern Blaine County-Western and Central Chouteau County. Flood Advisory until 6 PM MDT Monday for portions of Blaine, Hill, and Chouteau Counties. High Wind Warning until 9 AM MDT Monday for East Glacier Park Region-Northern High Plains. High Wind Watch from late Monday night through Tuesday evening for Cascade County below 5000ft-East Glacier Park Region-Eastern Glacier, Western Toole, and Central Pondera-Eastern Toole and Liberty-Gates of the Mountains-Northern High Plains-Southern High Plains-Southern Rocky Mountain Front-Upper Blackfoot and MacDonald Pass. High Wind Watch from Tuesday morning through Tuesday evening for Beaverhead and Western Madison below 6000ft-Big Belt, Bridger and Castle Mountains-Canyon Ferry Area-Elkhorn and Boulder Mountains-Fergus County below 4500ft-Gallatin Valley-Gallatin and Madison County Mountains and Centennial Mountains-Judith Basin County and Judith Gap-Little Belt and Highwood Mountains- Madison River Valley-Meagher County Valleys-Missouri Headwaters- Ruby Mountains and Southern Beaverhead Mountains-Snowy and Judith Mountains. && 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 MTBWG Browning (MTDOT) measured a gust of 60 mph.
Mesonet station mtm02 10.2 niles south of Loma measured a 58 mph gust.
Mesonet station MTBRN Two Medicine Bridge (MT DOT) measured a wind gust of 62 mph.
Mesonet station YCTIM Yellowstone Club measured a wind gust of 67 mph.
Mesonet station mtnor Norris Hill measured sustained winds, averaged over an hour, of 42 mph.
Awos station keks Ennis airport measured sustained winds, averaged over an hour, of 40 mph.
Mesonet station mtray Raynolds pass measured sustained winds, averaged over an hour, of 40 mph.
Mesonet station mtm05 arc-wtri Conrad measured a 63 mph gust.
Mesonet station MTM05 arc-wtri Conrad measured a wind gust of 63 mph.
Mesonet station gw1986 Lothair nine N measured a gust of 59 mph.
ASOS station KCTB Cut Bank Airport measured a gust of 58 mph.
Mesonet station delmt Dellwo measured a 66 mph gust.
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, April 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: 1093940, 1081429, 1093941, 1093943, 1081435, 1081436, 1081437, 1081438, 1093944, 1093942, 1093938, 1081439.