Scattered thunderstorms developed during the early afternoon hours from an unstable airmass over southwest Montana. A thunderstorm produced a small and very short- lived tornado near Dillon.
Every event with a place to put it. Tap one for its entry below.
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.
Scattered thunderstorms developed during the early afternoon hours from an unstable airmass over southwest Montana. A thunderstorm produced a small and very short- lived tornado near Dillon.
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 Jul 10, 10:48 AM MST, 42 minutes earlier.
Area Forecast Discussion National Weather Service Great Falls MT 1148 AM MDT SUN JUL 10 2016 ...Aviation Section Updated... .UPDATE...Unseasonably strong upper level low over the Pacific Northwest will move into western Montana by this evening. Short term models remain in good agreement that scattered showers will gradually transition to widespread showers and thunderstorms tonight. Overall forecast appears to be in good shape but have updated PoPs/weather to fine tune expected hourly progression of storms and to incorporate border changes from surrounding forecast offices. Have also updated the diurnal temperature trend which resulted in minor changes to max and min temperatures for some locations. mpj && .AVIATION...UPDATED 1748Z. Precipitation has been a bit slow in developing, but moisture associated with an upper level low over WA/OR continues to stream into the area. As precipitation fills in from south to north through tonight, CIGS will begin to lower with widespread MVFR CIGS and mountain obscurations likely at all TAF sites, especially this evening through Monday morning, with occasional IFR CIGS possible in the heaviest SHRA/TSRA. The greatest instability and best chance for TSRA today will be across SW MT and far eastern sections of central MT. TSRA cannot be ruled out elsewhere, but confidence is much lower due to lower instability. Any TSRA that develops today, especially vicinity KBZN, could produce gusty winds and hail. As the upper level low moves east on Monday, a strengthening W/NW wind will develop, especially by late Monday morning. Martin && .PREV DISCUSSION... /ISSUED / Today through Tuesday...Water vapor indicates a low pressure trof is moving on shore with the low centered over the Washington/Oregon coast. This low will eventually move across West Yellowstone as it moves east of the zones. Current radar echoes are associated with a disturbance moving through the southwest flow ahead of the trof. Some breaks in this shower activity will occur as this disturbance moves northeast. However, a jet will be moving into the southwest zones today, the air mass will become unstable over Southwest Montana, and widespread convection will develop. This will spread north as the system continues to approach the zones. A cold front will cross the northern and central zones today...but the strongest section of the front will cross the southwest zones between 00z and 06z Monday. This will be good focus for possible heavy rain in that region. Currently, the low pressure center is forecast to pass over West Yellowstone around 09z Monday. Temperatures will continue much cooler on Monday although some instability will develop by noon over the northeast zones. Otherwise, zones should generally be stable. With the system moving east during Monday night, the zones will no longer be under the strong lift associated with the low and precipitation will generally have ended. Some weak afternoon instability will develop Tuesday, however, and the northeast zones as well as the extreme southwest zones could see some showers or thunderstorms. Temperatures will be much cooler today...10 to 15 degrees below normals...remain cool Monday and begin to warm again Tuesday as high pressure builds aloft. Zelzer TUESDAY NIGHT THROUGH SUNDAY...Scattered showers and thunderstorms will decrease over the forecast area Tuesday night into Wednesday morning in the wake of the exiting low pressure system. A weak upper level high pressure ridge will then move into the area for Wednesday through Thursday, allowing any isolated showers and thunderstorms to mainly form over the mountains due to weak afternoon/evening instability. For the remainder of the period, there is some difference over last night's forecast, but the models all agree with this difference. The next weather system will move into the Pacific Northwest from the Gulf of Alaska Thursday into Friday, then linger there through the weekend. As a result, the forecast area will be under the influence of a moist and unstable southwest flow for Friday through the weekend, bringing scattered showers and thunderstorms. This differs from previous forecast runs in that models are quicker in bringing this system into the Pacific Northwest, thus forcing the high pressure ridge east of the area and allowing better coverage of showers/storms. Temperatures will remain fairly consistent through the period, staying between 5 degrees below normal and near normal. Coulston && .PRELIMINARY POINT TEMPS/POPS... GTF 67 51 66 48 / 50 90 90 20 CTB 71 52 66 48 / 20 80 50 30 HLN 65 49 67 49 / 90 80 70 10 BZN 67 46 65 43 / 80 80 70 20 WEY 60 38 54 37 / 90 70 60 10 DLN 63 44 63 43 / 90 80 50 10 HVR 75 54 68 54 / 20 100 80 50 LWT 65 51 64 49 / 80 80 90 30 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && weather.gov/greatfalls
The Missoula radar (KMSX), 227 km away, was scanning. The volume nearest the first event began at 18:32 UTC.
3 funnel cloud, 1 tornado, 1 hail. Local standard time, as filed.
Members of the public reported a tornado near Dillon. The tornado was short-lived and small.
Multiple calls reporting a funnel cloud near Highway 278 west of Dillon.
A thunderstorm dropped 1 inch diameter hail at Dillon 4SSE.
Madison County Sheriff's Deputy reported seeing a funnel cloud near Twin Bridges.
A funnel cloud was spotted near Grassrange.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2016Every state in 2016This day in weather historyThe tornado archive for Montana, 2016Warnings in Montana, July 2016
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: 635812, 635814, 635816, 635813, 635815.