Westerly flow aloft strengthens. Cross barrier flow causes strong winds along the Rocky|Mountain Front.
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.
Westerly flow aloft strengthens. Cross barrier flow causes strong winds along the Rocky|Mountain Front.
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 13, 4:08 AM MST, 2 hours 22 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 408 AM MST Thu Dec 13 2018 ...Aviation Discussion Update... .SYNOPSIS.. Strong west winds along the Rocky Mountain Front this morning will spread east out onto the plains and south over the ridge tops of southwest Montana today, as some light snow remains over the western mountains. High pressure building in from the south will diminish any lingering snow and decrease winds somewhat tonight into Friday. However, a Pacific disturbance will bring another round of mountain precipitation and potentially strong winds to the region for Saturday. Temperatures will remain above normal, with especially mild temperatures over the plains. && .DISCUSSION... Today through Saturday...The westerly flow aloft over Montana has strengthened overnight, bringing strong winds to the Rocky Mountain Front once again and keeping light snow above mountain pass level along the Rocky Mountain Front. These winds will likely spread east out onto the plains throughout the morning. Sustained winds of 35 to 45 mph with gusts to 65 mph will be likely along the Front and onto immediate adjacent plains, but gusts could reach 85 mph closer to the Front itself. Will therefore continue the High Wind Warning there through today. Of concern is the potential for these increased winds to cause ground blizzard conditions due to the newly fallen snow in the mountains, especially over Marias Pass. Winds will become more diffuse as they spread out over the plains, mainly bringing 35 to 50 mph gusts there. Ridge tops and a few other favored canyons in southwest Montana may also see gusts this strong. The high pressure ridge will build further into the forecast area overnight into Friday, which will diminish any lingering precipitation and cause winds to be not quite as strong, but still quite breezy. A low pressure trough will then move from the Pacific Northwest across Montana Friday night through Saturday. This will help strengthen westerly winds again across the area, which may require additional High Wind highlights for the Rocky Mountain Front. It will also bring a good chance of snow to the mountains along the Continental Divide. Mild December temperatures of 10 to 15 degrees above normal will continue over the plains, but southwest Montana will remain only up to 10 degrees above normal. Coulston Saturday night through Wednesday night...main forecast concerns over the long term period of the forecast are strong winds along the Rocky Mountain Front, primarily mountain/mountain pass snow, and above normal temperatures over the plains of North Central Montana and valleys of Southwest Montana. Upper level pattern to begin the long term will see a ridge building and sliding east into the Northern Rockies through the morning hours on Monday. An open wave over the Pacific Northwest Monday morning, will then quickly race east through the day on Monday, crossing the Northern Rockies and moving into the Northern High Plains Monday evening/early Tuesday morning. As this wave slides east, it will begin to break down the ridge overhead, which is generally a good synoptic setup for breezy to gusty winds over the region. Following the passage of the wave, upper level ridging will slowly build back into the Northern Rockies through Wednesday night, with primarily southwest flow aloft across the region over this time. At the surface, despite upper level ridging moving overhead Saturday night, surface pressure gradient will remain strong along the Rocky Mountain Front from the overnight hours on Saturday and into Sunday morning. This will lead to continued breezy to windy conditions here. These conditions will then overspread the plains of NC Montana as the wave crosses the region, however, High Winds are not expected at this time. The transition to southwest flow aloft will bring a return to some precipitation, in the form of snow, to the Continental Divide and mountains of SW Montana. It should be noted that significant differences do exist between model guidance with how much precipitation is possible over this timeframe, which gives below normal confidence in amounts of QPF/snow. Finally, strong winds look to setup shop once again along the Rocky Mountain Front from Tuesday afternoon through Wednesday night. - Moldan && .AVIATION... Updated 12Z TAF. Expect predominantly VFR conditions with periods of MVFR due to CIG BKN030 at KBZN and KEKS. Expect strong gusty winds with low level wind shear occurring throughout the forecast area. -Fogleman && .PRELIMINARY POINT TEMPS/POPS... GTF 46 33 53 32 / 0 0 0 10 CTB 45 30 53 29 / 0 0 0 0 HLN 44 21 44 25 / 0 0 0 10 BZN 40 15 42 23 / 0 0 0 10 WEY 27 1 34 13 / 10 10 0 30 DLN 37 10 38 18 / 0 0 0 10 HVR 47 28 56 30 / 10 10 0 0 LWT 42 28 53 31 / 10 10 0 10 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 5 PM MST this afternoon Eastern Glacier...Northern Rocky Mountain Front...Southern Rocky Mountain Front. && http://www.weather.gov/greatfalls
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
207 AM MST THU DEC 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0147 AM NON-TSTM WND GST 3 SW CUT BANK 48.60N 112.38W
12/13/2018 M56 MPH GLACIER MT ASOS
&&
MOLDANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
311 AM MST THU DEC 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1035 PM NON-TSTM WND GST 6 WNW BROWNING 48.59N 113.14W
12/11/2018 M75 MPH GLACIER MT PUBLIC
REPORT RELAYED VIA SOCIAL MEDIA FROM A
BROADCAST MEDIA SITE. LOCATION AND TIME ARE
ESTIMATES FROM THE REPORT.
&&
MOLDANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
328 AM MST THU DEC 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0300 AM HIGH SUST WINDS 3 SW CUT BANK 48.60N 112.38W
12/13/2018 M41 MPH GLACIER MT ASOS
BETWEEN 0100 AND 0300 LST THE AVERAGE WIND
SPEED AT CUT BANK AIRPORT WAS SUSTAINED AT
41 MPH. THE PEAK WIND GUST OVER THIS TIME
FRAME WAS 56 MPH AT 0156 LST.
&&
MOLDANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
332 AM MST THU DEC 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0245 AM NON-TSTM WND GST 14 W BYNUM 47.98N 112.61W
12/13/2018 M58 MPH TETON MT MESONET
&&
MOLDANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
408 AM MST THU DEC 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0351 AM NON-TSTM WND GST 3 SW CUT BANK 48.60N 112.38W
12/13/2018 M60 MPH GLACIER MT ASOS
&&
MOLDANPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
433 AM MST THU DEC 13 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0521 AM SNOW EAST GLACIER PARK 48.44N 113.22W
12/12/2018 M3.5 INCH GLACIER MT BROADCAST MEDIA
CORRECTS PREVIOUS SNOW REPORT FROM EAST
GLACIER PARK.
&&
MOLDAN3 high wind. Local standard time, as filed.
High winds gust of 81 mph measured at mesonet station delmt, dellwo - 13 w bynum.
High wind gust of 59 mph measured at asos station gtf, great falls airport.
High winds gust of 58 mph measured at mesonet station mtgys, geyser us87 mdt.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2018Every state in 2018This day in weather historyWarnings in Montana, December 2018
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: 796749, 797093, 797095.