On August 2nd, isolated to scattered showers and thunderstorms developed over central and southwest MT, along and ahead of a shortwave trough and cold front approaching from the west. A couple of storms managed to produce marginally-severe wind gusts as precipitation transported stronger winds aloft down to the surface.
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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.
On August 2nd, isolated to scattered showers and thunderstorms developed over central and southwest MT, along and ahead of a shortwave trough and cold front approaching from the west. A couple of storms managed to produce marginally-severe wind gusts as precipitation transported stronger winds aloft down to the surface.
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 Aug 2, 1:16 PM MST, 1 hour 43 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 216 PM MDT Thu Aug 2 2018 .SYNOPSIS... Hot, dry, and breezy conditions will continue the severe fire weather threat through Friday. The passage of a cold front tonight will cause winds to increase further on Friday over the plain, although temperatures will cool back closer to normal. A few storms may also redevelop over far southwest Montana again on Friday. This weekend will bring cooler temperatures with a chance of showers and thunderstorms for much of the region. && .DISCUSSION... Rest of this Afternoon through Friday Night...Hot and dry conditions with breezy west winds across the area, along with isolated to widely scattered dry thunderstorms over the southwest, will be the main concerns this period. A shortwave low pressure trough will move into the Pacific Northwest through tonight, which will start to flatten the high pressure ridge over the area. The resulting increasing southwest flow aloft will continue the spread of wildfire smoke aloft, keeping haze in the forecast. A dry Pacific cold front with an associated thermal trough will help to fire off a mix of mostly dry but some wet thunderstorms over southwest Montana this afternoon and evening. Some of these storms may produce frequent lightning and become severe by mixing down damaging wind gusts up to 60 mph. The front will also help translate the gusty mid-level west winds down to the surface, especially along the Rocky Mountain Front, where wind gusts could reach 35 mph. After the cold front passes through the area overnight, the shortwave will move through the area on Friday, further increasing the gusty west winds and likely forcing much of the smoke south out of the area. Gusts to 35 mph will be possible over the plains, but gusts could reach 50 mph along the Rocky Mountain Front. Another round of thunderstorms will also be possible over far southwest Montana. Temperatures will warm to around 10 degrees above normal today, then cool back closer to normal for Friday. For more details on the impacts of the dry and breezy conditions, please check out the Fire Weather section. Saturday through next Thursday...A high pressure ridge aloft builds from the west this weekend, but will also be undercut by multiple eastward-moving shortwave disturbances. Accordingly, near-normal lows and below-normal highs are forecast this weekend, as are isolated showers and thunderstorms. The best potential for these showers/storms will be over and near higher terrain and across the Hi-Line. The high pressure ridge aloft then builds further over our region Monday through Thursday of next week, resulting in a drying and warming trend. Near-normal lows and highs on Monday will be followed by primarily above- normal readings Tuesday through Thursday. At this time, critical fire weather conditions are not anticipated during the long term period. && .AVIATION... Updated 1703Z. VFR conditions will continue through the next 24 hours. The haze over much of the area will decrease later tonight with the passage of a Pacific cold front. Otherwise, skies will remain mostly clear over the plains with breezy west winds during the afternoon and evening and possibly even much of the overnight. Most gusts will be as high as 30 kt, but gusts to 45 kt are possible along the Rocky Mountain Front. Scattered high-based thunderstorms with wind gusts of up to 50 kt are possible over southwest Montana and northeast into the KLWT area between 18Z and 06Z as the airmass there destabilizes. Winds and storms should begin decreasing after 03Z. && .FIRE WEATHER... The Red Flag Warning remains in effect from through midnight Friday night for all of the TFX fire weather zones. Hot and dry conditions this afternoon and evening will combine with breezy west winds to create critical fire weather conditions over the forecast area, especially over the plains, as any new fire starts could spread rapidly. A dry Pacific cold front will then move through the area overnight continuing the gusty winds with only moderate humidity recovery. For Friday, a shortwave trough will move through the area, further increasing the westerly winds. Although temperatures on Friday will be up to 10 degrees cooler than today, the airmass will still be quite dry, as humidity falls into the 10 to 20 percent range. Conditions should improve into Saturday, as temperatures cool further and winds decrease. NWS Missoula also has a Red Flag Warning in effect from noon through 10 pm today for fire weather zones 110 and 111, including portions of Jefferson, Madison, and Beaverhead Counties. Scattered mainly dry thunderstorms may could produce strong gusty winds and frequent lightning, and gusty west winds will combine with low relative humidity create critical fire weather conditions. Similar conditions are expected Friday afternoon and evening, prompting the issuance of a Red Flag Warning for then as well. && .PRELIMINARY POINT TEMPS/POPS... GTF 56 87 51 77 / 10 0 10 20 CTB 53 82 51 75 / 0 0 10 30 HLN 55 86 53 78 / 10 10 10 10 BZN 51 85 47 78 / 30 20 20 10 WEY 43 78 37 72 / 50 30 20 10 DLN 50 83 43 76 / 20 10 10 10 HVR 57 90 54 79 / 10 0 0 20 LWT 56 83 51 75 / 30 10 10 10 && .TFX WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until midnight MDT Friday night Central and Eastern Lewis and Clark National Forest Areas...Chouteau and Fergus Counties...Eastern Glacier/Toole/Central/Eastern Pondera/Liberty...Helena and Townsend Ranger Districts of the Helena National Forest...Hill and Blaine Counties...Lewis and Clark National Forest Rocky Mountain District-Rocky Mountain Front...Lincoln Ranger District of the Helena National Forest. Red Flag Warning until 10 PM MDT this evening Eastern Beaverhead National Forest. Red Flag Warning from noon to 10 PM MDT Friday Deerlodge/Western Beaverhead National Forest...Eastern Beaverhead National Forest. Red Flag Warning until 10 PM MDT this evening Deerlodge/Western Beaverhead National Forest. && http://www.weather.gov/greatfalls
The Pocatello radar (KSFX), 177 km away, was scanning. The volume nearest the first event began at 22:00 UTC.
2 thunderstorm wind. Local standard time, as filed.
Antelope RAWS, about five-miles NE of Lima, reported 58-mph peak gust from thunderstorm.
Lewistown Airport ASOS reported 58-mph peak gust from thunderstorm.
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, August 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: 764123, 764124.