An upper level trough crosses North Central and Southwestern Montana, quickly tracking across Montana throughout the day. Windy conditions continue to increase during the morning hours, peaking along The Rocky Mountain Front and over much of North Central Montana through the afternoon hours.
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 level trough crosses North Central and Southwestern Montana, quickly tracking across Montana throughout the day. Windy conditions continue to increase during the morning hours, peaking along The Rocky Mountain Front and over much of North Central Montana through the afternoon hours.
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 15, 4:31 AM MST, 2 hours 26 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 431 AM MST Sat Dec 15 2018 .SYNOPSIS... Areas of rain and mountain snow continue to develop over western Montana, getting caught up along the divide and mostly drying out before reaching Northcentral Montana. Gusty winds have started to increase over much of the Northcentral Montana, especially along the Rocky Mountain Front and Plains areas directly to the east. Mild and breezy conditions continue through the weekend. && .DISCUSSION... Today through Sunday night...An energetic upper level trough has started crossing Northcentral and Southwestern Montana today, quickly tracking across Montana throughout the day today. Windy conditions will continue to increase this morning, peaking along the Rocky Mountain Front late this morning, and over much of Northcentral Montana through the afternoon hours. A High Wind Warning remains in effect for expected high winds in this area of enhanced mountain wave activity. The moist westerly flow has started to produce some mountain snow over the Northern Rockies overnight last night and into this morning, where 2-4 inches of new snow is possible for the remote backcountry terrain. Lighter snowfall is also expected over the southern end of the Madison range in far southwest MT. Subsidence behind the passing upper level trough, combined with deeper boundary layer mixing this afternoon could cause a period of more widespread stronger wind gusts with the departing surface low. Skies clear across the region later this afternoon. A period of weak upper level ridging shifts across the region tonight through Sunday night will bring some drier conditions to the area. -TP Sunday night through Saturday...West to southwest flow aloft increases again Mon/Mon night as a weakening shortwave trough moves across the Northern Rockies. Main impact period of next week looks to occur Tues/Wed As a strong Pacific upper level jet moves onshore with an associated moisture plume directed across the Northern Rockies late Tuesday through Wednesday morning. This will bring rain and high elevation snow to areas along the continental divide with a few showers also potentially making it east of the divide with the passage of an associated frontal system Tuesday night. Most areas however will see another period of stronger winds late Tuesday through Wednesday as this system moves through. An upper level ridge rebuilds over the Western US for late Wednesday through Thursday before models diverge with respect to the timing and trajectory of the following round of incoming shortwave energy from the Pacific. Temperatures will remain well above seasonal averages through much of next week with some cooling possible late next week into the following weekend. -Hoenisch && .AVIATION... Updated 1125Z. Increasing mid/high level clouds tracking across the region through the period, with steadily increasing strong winds near the surface, leading to some terminals experiencing some low level wind shear this morning. The upper level trough moves through today, with windy/strong winds expected in many areas today. Winds should decrease tonight, and the trough tracks further eastward across the state. Some western mountains/passes could be obscured at times through the period. -TP && .PRELIMINARY POINT TEMPS/POPS... GTF 44 32 49 34 / 0 0 0 0 CTB 41 28 45 31 / 0 0 0 0 HLN 41 25 43 24 / 0 0 0 0 BZN 39 21 42 21 / 0 0 0 0 WEY 29 16 36 11 / 20 0 0 0 DLN 36 20 40 20 / 0 0 0 0 HVR 44 26 45 27 / 0 0 0 0 LWT 42 28 48 32 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 2 PM MST this afternoon Eastern Glacier. High Wind Warning until 2 PM MST this afternoon Northern Rocky Mountain Front...Southern Rocky Mountain Front. && http://www.weather.gov/greatfalls
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
531 AM MST SAT DEC 15 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0316 AM NON-TSTM WND GST 5 WSW GREAT FALLS 47.47N 111.38W
12/15/2018 M55 MPH CASCADE MT ASOS
ASOS STATION GTF, GREAT FALLS AIRPORT.
&&PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
604 AM MST SAT DEC 15 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0502 AM NON-TSTM WND GST 1 SW ULM 47.42N 111.52W
12/15/2018 E52 MPH CASCADE MT TRAINED SPOTTER
CURRENTLY GUSTING 18G30MPH, HAD PEAK GUSTS
AT 3:05AM AT 52MPH.
&&
TP3 high wind. Local standard time, as filed.
High wind gust of 61 mph reported by the Dept of Highways at Norris Hill dot weather station 4 NNE McAllister.
High wind gust of 66 mph measured at dellwo mesonet station 14 W Bynum.
High wind gust of 61 mph reported by Dept of Highways at two medicine bridge dot weather station 1 ENE East Glacier Park.
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: 797097, 796791, 797098.