Upper level ridge moving into the Northern Rockies will begin to flatten out as a potent open wave digs southeastward from the Gulf of Alaska and into the Canadian Rockies. At the surface, a lee-side surface trough sharpens rapidly as the surface low moves southeast from West Central British Columbia and into Central Alberta.
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.
Upper level ridge moving into the Northern Rockies will begin to flatten out as a potent open wave digs southeastward from the Gulf of Alaska and into the Canadian Rockies. At the surface, a lee-side surface trough sharpens rapidly as the surface low moves southeast from West Central British Columbia and into Central Alberta. This sharpening lee-side surface trough will lead to an increasing pressure gradient along the Rocky |Mountain Front (and eventually along the north facing slopes of the Little Belt Mountains), with values peaking out at between 175-250 microbars/km.
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 28, 7:51 PM MST, 1 hour 46 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 751 PM MST Fri Dec 28 2018 .UPDATE... Updated current max temperatures as some warmer air filters into the area tonight under increasing south to southwesterly flow. Otherwise, forecast remain on track for windy and snowy conditions to track across the forecast area this weekend. && .SYNOPSIS... Strong winds will develop along the Rocky Mountain Front and overspread the plains of North Central Montana on Saturday. These strong winds will persist through Saturday night. A strong cold front will then dive across the state on Sunday, bringing accumulating snow to mountains and some plains locations. && .AVIATION... Updated 0000Z. VFR conditions will persist through tonight. MVFR conditions could return by early Saturday morning with a system bringing some snow showers. Winds will also be steadily increasing through the period. && .PREV DISCUSSION... /ISSUED 239 PM MST Fri Dec 28 2018/ Tonight through Sunday night...primary forecast concerns over the weekend are strong winds and accumulating snow. Upper level ridge moving into the Northern Rockies tonight into Saturday morning will begin to flatten out as a potent open wave digs southeast from the Gulf of Alaska and into the Canadian Rockies by Saturday evening. At the surface, lee-side surface trough will sharpen rapidly tonight into Saturday morning as the surface low moves southeast from West Central British Columbia and into Central Alberta by Saturday evening. This sharpening lee-side surface trough will lead to an increasing pressure gradient along the Rocky Mountain Front (and eventually along the north facing slopes of the Little Belt Mountains), with values peaking out at between 175-250 microbars/km, which is some of the highest values I've seen thus far this fall/winter season. H700 cross barrier flow of 30-50kts Saturday morning over the Divide, will increase and expand further east over the plains into the early morning hours on Sunday. These H700 winds are expected to peak Saturday evening over the Divide and portions of the plains of North Central Montana at around 60-90kts (with the strongest winds focused immediately downwind of the Rocky Mountain Front). The combination of a very impressive pressure gradient along the Rocky Mountain Front and increasing cross barrier flow has raised confidence that High Winds will occur Saturday morning into Sunday morning. Have therefore issued a High Wind Warning for the Rocky Mountain Front from 06z Saturday-15z Sunday, and for Eastern Glacier/Toole/Eastern Pondera/Eastern Teton Counties from 12z Saturday-15z Sunday. Wind gusts approaching 100 mph are possible in wind favored regions of the Rocky Mountain Front, with 70 mph winds over the plains of North Central Montana along and west of Interstate 15. Further east and south were confidence in High Winds occurring was still not high enough to upgrade to a warning, a High Wind Watch is/remains in effect for Liberty/Hill/Blaine/Chouteau/Central and Southern Lewis and Clark/Cascade/Judith Basin/Fergus Counties from 15z Saturday-15z Sunday. H500 height falls of 100-150m Sunday morning will overspread the Northern Rockies as the open wave digs into the region. At the surface, low pressure over Southern Saskatchewan Sunday morning will quickly race southeast into the Eastern Dakota's/Western Minnesota by Sunday evening. A trailing cold front from this surface low will dive south from Canada and across North Central Montana Sunday morning and across Southwest Montana Sunday afternoon/evening. 6hr pressure rises of 6-12mb behind the cold front will provide another period of strong/gusty winds over the entire region, with falling temperatures as strong cold air advection ensues. Snow will develop along the Continental Divide Saturday ahead of the cold front, with snow developing along and behind the cold front on Sunday across the entire region. Strong upslope flow over the Little Belt Mountains will focus snow accumulations of 6-12" at Kings Hill Pass, with a fairly large area of 4-6" over the remainder of the Little Belts. Snowfall accumulations of 8-12" are possible along the immediate Divide including Marias Pass from Saturday night through Sunday afternoon, with 4-6" at East Glacier, and 2-4" at Babb/Heart Butte. Snow accumulations at most passes across Southwest Montana of 4-8" is also possible. The combination of falling snow and expected windy conditions has raised confidence that a period of very difficult travel will be possible along the Rocky Mountain Front, Southwest and portions of North Central Montana. For this reason, a Winter Storm Watch has been issued for these areas. - Moldan Monday starts out colder with snow exiting to the southeast. Models keep a light northerly flow with the low center to the east and, pending terrain blocking ability, this could mean light snow lingering into mid Monday. Conditions clear out into Tuesday morning which should mean continued cold morning temperatures, perhaps single digits in many locations. Weak high pressure builds in over Montana Tuesday into Wednesday ahead of a trough approaching the Pacific NW late next week. As these features merge, expect strong winds to return Thursday into Friday, especially along the Northern Rocky Mountain Front. - Gustafson && .PRELIMINARY POINT TEMPS/POPS... GTF 22 45 30 35 / 0 20 10 80 CTB 24 45 27 31 / 10 10 20 60 HLN 17 41 29 36 / 10 60 30 60 BZN 11 34 26 34 / 0 80 30 70 WEY -2 16 7 22 / 10 100 80 90 DLN 8 33 22 31 / 0 30 30 50 HVR 16 44 28 33 / 10 20 30 60 LWT 10 43 28 33 / 0 20 20 70 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Watch from Saturday morning through Sunday morning Blaine...Cascade...Central and Southern Lewis and Clark... Chouteau...Fergus...Hill...Judith Basin...Liberty. Winter Storm Watch from Saturday afternoon through Sunday afternoon Central and Southern Lewis and Clark...Jefferson. Winter Storm Watch from Saturday afternoon through Sunday afternoon Beaverhead...Gallatin...Madison. Winter Storm Watch from Saturday evening through Sunday afternoon Broadwater...Cascade...Judith Basin...Meagher. High Wind Warning from 5 AM Saturday to 8 AM MST Sunday Eastern Glacier...Eastern Pondera...Eastern Teton...Toole. Winter Storm Watch from Saturday afternoon through Sunday afternoon Northern Rocky Mountain Front...Southern Rocky Mountain Front. High Wind Warning from 11 PM this evening to 8 AM MST Sunday Northern Rocky Mountain Front...Southern Rocky Mountain Front. && http://www.weather.gov/greatfalls
1 high wind. Local standard time, as filed.
High wind gust of 63 mph measured at mesonet station mtbrn, two medicine bridge 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: 796910.