A fast west to northwesterly flow aloft continues over the region, with mid-level flow around 50kts through the morning.
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.
A fast west to northwesterly flow aloft continues over the region, with mid-level flow around 50kts through the morning.
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 18, 10:55 PM MST, 3 hours 42 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 1055 PM MST Tue Dec 18 2018 Updated Aviation Discussion .UPDATE... 740 PM MST update...Will not be making any further adjustments to current forecast. Bands of snow will move south along the Continental Divide overnight, continuing the (at least) light snow accumulation in the mountains and on the mountain passes; so will leave the Winter Weather Advisory in effect. Winds have been strong in the High Wind Warning area, with a number of places already exceeding High Wind criteria earlier today, but they have generally stayed below criteria this afternoon and evening. However, the disturbance responsible for the winds should continue to advect cooler air into the area into Wednesday, which may still cause some sporadic strong gusts. Will therefore leave the High Wind Warning in effect as well. Am a bit uncertain about temperatures as well (might be a little cool), but it seems like there could be enough of a lull in winds or break in clouds to allow temperatures to fall into the forecasted range. Coulston 552 PM MST update...Quick update to forecast to add areas along the Continental Divide south through central and southern Lewis and Clark County to the Winter Weather Advisory above 5000 feet. Minor snow accumulations can be seen on MT DOT web cameras at both MacDonald Pass and Rogers Pass. Now that the sun has set, light snow should continue to accumulate there, making travel difficult due to snow packed and icy roads, with some blowing snow possible. This Advisory does not include the Helena and Lincoln areas at this time. Will consider further updates to the forecast in general over the next couple of hours. Coulston && .SYNOPSIS... A strong Pacific storm system moves into the northern Rockies and then the rest of the Treasure State, today, bringing strong winds to most of central Montana east of the Continental Divide, spreading into south-central portions of the State on Wednesday. Rain and mountain snow, which may be heavy at times, will develop over areas along and west of the Continental Divide today while areas of snow develop over adjacent portions of southwest Montana this afternoon and tonight. && .AVIATION... Updated 0600Z. Strong moist and somewhat unstable westerly flow aloft continues over the region tonight, veering to more northwesterly on Wednesday. Snow showers continue over the Continental Divide with occasional bands of snow showers (possibly mixed with rain below 5000 ft) moving across SW MT. These showers could bring brief periods of MVFR conditions to KBZN and KEKS and possibly as far north as KHLN through about 12z Wed. Drier flow aloft and some clearing develops as winds aloft shift to northwesterly Wednesday afternoon. Surface winds will remain quite gusty at all terminals tonight through Wednesday morning before winds begin a gradual diminishing trend Wednesday afternoon and evening. Significant Mtn wave turbulence and low level wind shear impacts to continue through Wednesday morning. Hoenisch && .PREV DISCUSSION... /ISSUED 445 PM MST Tue Dec 18 2018/ Today and Tomorrow...Satellite imagery reveals a strong upper level jet and moisture plume moving into WA/OR south of a vigorous/stacked low moving toward the AK panhandle. Little change in the overall impacts expected as this moisture and region of strong flow aloft moves east into the region today and tonight, bringing widespread strong winds to much of central MT and heavy snow accumulations to areas along the Continental divide with winds and mountain snow decreasing Wednesday as an upper level ridge rebuilds along the West coast. Strong wind gusts have developed along the immediate east slopes of the Rocky Mtn Front as the initial surge of strong west flow aloft arrived in combination with favorable temperature/wind profiles for Mtn Wave/downslope wind enhancement. Strong west flow aloft overspreads much of north- central MT today, with gusts peaking this evening. Strongest winds for eastern and southern portions of central MT are most likely to occur with the passage of the associated Pacific surface cold front/trough this evening. Very windy conditions are likely to continue into Wednesday morning for many areas with winds gradually diminishing Wednesday afternoon. Snow increases across areas along the Continental Divide west of the Rocky Mtn Front then spreads across the higher elevations of SW MT near the ID border. Downslope drying will likely keep lower elevations dry through this afternoon but snow showers will become more widespread across SW MT and southern portions of central MT tonight as stability decreases with incoming colder air aloft behind the front. Heaviest snow accumulation and winter weather impacts are expected near Marias Pass today and tonight where a winter weather advisory is in place. A winter weather advisory is also in effect for Beaverhead County, including Big Hole Pass and Chief Joe Pass. Several inches of snow accumulation is possible across the Mtns of SW MT tonight from multiple rounds of snow showers. Hoenisch Wednesday night through Tuesday...The progressive pattern that we have been in for the past or so looks to continue through the early part of next week. The ongoing pattern of shortwave troughs followed by shortwave ridges will continue to shift the weather regimes from wet and windy weather, mild and dry weather. The focus for impactful weather remains on the passage of shortwave troughs Thursday night into Friday, Sunday morning into Monday morning, and again on Tuesday. The initial trough Thursday night into Friday looks to bring another round of gusty winds and mountain snowfall to the area, especially along the Rocky Mountain Front. The next system currently looks weaker in the models with regards to precipitation along the mountains and gusty winds. The final system on Tuesday looks to be the weakest with regards to the winds, but has more precipitation making it over The Divide as there should be less downsloping effect with the weaker cross- barrier flow. However, confidence at this time is lower with regards to the second and third systems from Sunday into Tuesday, due to these scenarios being further out in the forecast period and current discrepancies between the different model runs during this timeframe. -TP && .PRELIMINARY POINT TEMPS/POPS... GTF 35 47 30 51 / 10 0 0 0 CTB 34 43 28 45 / 20 0 0 10 HLN 32 45 25 42 / 30 10 0 0 BZN 27 43 19 41 / 40 10 0 0 WEY 20 30 14 31 / 80 30 10 0 DLN 26 39 18 37 / 40 10 0 0 HVR 35 47 25 45 / 10 0 0 10 LWT 32 42 24 46 / 0 0 0 0 && .TFX WATCHES/WARNINGS/ADVISORIES... High Wind Warning until 5 PM MST Wednesday Broadwater... Cascade...Central and Southern Lewis and Clark...Chouteau... Eastern Glacier...Eastern Pondera...Eastern Teton...Fergus... Jefferson...Judith Basin...Liberty...Meagher...Toole. Winter Weather Advisory until 8 AM MST Wednesday above 5000 feet for Central and Southern Lewis and Clark...Northern Rocky Mountain Front...Southern Rocky Mountain Front. Winter Weather Advisory until 8 AM MST Wednesday above 6500 feet for Beaverhead. High Wind Warning until 8 AM MST Wednesday Blaine...Hill. High Wind Warning until 5 PM MST Wednesday Northern Rocky Mountain Front...Southern Rocky Mountain Front. && http://www.weather.gov/greatfalls
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GREAT FALLS MT
1101 PM MST TUE DEC 18 2018
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0830 PM NON-TSTM WND GST SUNBURST 48.88N 111.90W
12/18/2018 M62 MPH TOOLE MT MESONET
MESONET STATION MTSUN, SUNBURST MDT.
&&1 high wind. Local standard time, as filed.
High wind gust of 60 mph measured at mesonet station mtpnd, pendroy 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: 796898.