Severe thunderstorms developed over southwest Montana on consecutive afternoons. Hail up to quarter-size and thunderstorm wind gusts of up to 66 mph were reported.
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.
Severe thunderstorms developed over southwest Montana on consecutive afternoons. Hail up to quarter-size and thunderstorm wind gusts of up to 66 mph were reported.
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, 1:58 PM MST, 32 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 258 PM MDT TUE JUL 10 2012 .DISCUSSION... TONIGHT THROUGH THURSDAY...UPPER TROF MOVING ACROSS THE AREA NOW BEGINNING TO INITIATE ISOLATED THUNDERSTORMS. CURRENT LAPS ANALYSIS INDICATES AN AIRMASS WITH CAPE VALUES OF 1500 TO 2500 J/KG AND LI VALUES OF -1 TO -4. ISOLATED TO SCATTERED THUNDERSTORMS WILL CONTINUE THROUGH THE EARLY EVENING. STRONG WINDS THE MAIN THREAT FROM THESE STORMS AS A VERY HIGH WET BULB ZERO HEIGHT NOT CONDUCEIVE TO LARGE HAIL. A LACK OF FORCING AND VERY WEAK LOW LEVEL FLOW WILL ALSO WORK TOWARD KEEPING THESE STORMS UNDER SEVERE CRITERIA. SOME STORMS OVER SOUTHWEST MONTANA MAY NOT CONTAIN SIGNIFICANT RAIN. WITH AFTERNOON RELATIVE HUMIDITY VALUES BELOW 20 PERCENT...CRITICAL FIRE CONDITIONS WILL CONTINUE AS WILL THE RED FLAG WARNING. ISOLATED THUNDERSTORMS WILL AGAIN BE POSSIBLE ON WEDNESDAY AS THE AIRMASS REMAINS WARM AND MOISTURE FROM THE SOUTHWEST U.S. CONTINUES TO BE TAPPED. RISING 500 MB HEIGHTS ON THURSDAY WILL PROVIDE SUBSIDENCE HEATING BUT GENERALLY DRY CONDITIONS. TEMPERATURES WILL REMAIN ABOVE SEASONAL AVERAGES. EMANUEL THURSDAY NIGHT THROUGH WEDNESDAY...HIGH PRESSURE WILL HOLD OVER THE REGION THROUGH FRIDAY AS SCATTERED MOISTURE ASSOCIATED WITH MONSOONAL FLOW CONTINUES TO MOVE INTO MONTANA FROM THE SOUTH. AS A RESULT...BOTH WEST AND SOUTHWEST MONTANA WILL SEE THE BEST CHANCE FOR SHOWER AND THUNDERSTORM DEVELOPMENT. THERE WILL ALSO BE A CHANCE OF ACTIVITY OVER CENTRAL AND NORTH-CENTRAL MONTANA AS STORMS DRIFT OFF TERRAIN. WITH THIS FLOW ACTIVITY WILL BE SHOWERY AND SCATTERED IN NATURE. AS A RESULT...HAVE KEPT SLIGHT CHANCE TO CHANCE POP THROUGH FRIDAY AS MODEL AGREEMENT IS MARGINAL. FRIDAY NIGHT INTO SATURDAY A LOW PRESSURE SYSTEM IN THE PACIFIC NORTHWEST LOOKS TO PUSH A FRONTAL BOUNDARY INTO MONTANA FROM THE SOUTHWEST. THIS FEATURE WILL BRING THE POTENTIAL FOR MORE WIDESPREAD SHOWER ACTIVITY SATURDAY AND SUNDAY ALONG WITH SOMEWHAT COOLER TEMPERATURES SO HAVE RAISED POP SOME OVER THIS TWO DAY PERIOD. OVERALL SYNOPTIC FLOW WILL SHIFT ON SUNDAY AS THE REGION COMES UNDER A WEST TO SOUTHWEST FLOW ALOFT. GFS BRINGS A TROUGH INTO THE REGION FROM THE WEST MID-WEEK BUT ECMWF CONTINUES WESTERLY FLOW SO CONFIDENCE IS FAIRLY LOW ON THIS EVENT AT THE CURRENT TIME. WINDS WILL BE MOSTLY LIGHT AND VARIABLE WITH AFTERNOON BREEZINESS THROUGHOUT THE LONG TERM PERIOD. PRECIPITATION OUTLOOK THROUGH THE LONG TERM FORECAST REMAINS POOR OVERALL WITH THE EXCEPTION OF THE TROUGH SATURDAY INTO SUNDAY. AFTERNOON HIGH TEMPERATURES WILL RANGE FROM THE UPPER 80S TO MID 90S BUT MAY COOL SOME EARLY NEXT WEEK. OVERNIGHT LOWS WILL BE IN THE 50S TO LOW 60S. && .AVIATION... UPDATED 1800Z. OVERALL VFR CONDITIONS ARE EXPECTED BUT BRIEF MVFR CONDITIONS ARE POSSIBLE WITH AFTERNOON SHOWERS AND THUNDERSTORMS. WEAK THUNDERSTORMS ARE INITIATING ALONG THE CONTINENTAL DIVIDE AND SOUTHWEST MONTANA EARLY THIS AFTERNOON AND THESE WILL CONTINUE TO MOVE INTO CENTRAL MONTANA AND BECOME MORE WIDESPREAD THIS AFTERNOON AS INSTABILITY INCREASES. THE MAIN THREAT FROM THESE STORMS WILL BE GUSTY AND ERRATIC WINDS AND LIGHTNING...BUT BRIEF HEAVY RAINFALL WILL ALSO BE POSSIBLE...PARTICULARLY OVER NORTH-CENTRAL MONTANA WHERE THERE IS BETTER MOISTURE AVAILABILITY. MOUNTAIN OBSCURATION IS EXPECTED IN AND NEAR CONVECTIVE ACTIVITY. STORMS WILL DECREASE FROM THE WEST AFTER 02Z RETURNING TO CALMER CONDITIONS OVERNIGHT. MLV && .FIRE WEATHER... AN INCREASING CHANCE OF THUNDERSTORMS REMAINS IN PLACE FOR MUCH OF THE DISTRICTS THIS AFTERNOON AND EVENING. IN SOUTHWEST MONTANA THE THREAT FOR DRY THUNDERSTORMS CONTINUES TO LOOK FAVORABLE. IN ASSOCIATION WITH THE MISSOULA AND BILLINGS FORECAST OFFICES AND SPC HAVE UPGRADED THE FIRE WEATHER WATCH TO A RED FLAG WARNING FOR INCREASED COVERAGE OF THUNDERSTORMS AFTER A DRY SPELL. AM EXPECTING THAT MANY OF THESE STORMS WILL PUT OUT GUSTY AND ERRATIC WINDS POSSIBLY IN EXCESS OF 50 MPH. MPJ && .PRELIMINARY POINT TEMPS/POPS... GTF 61 91 59 93 / 30 20 20 10 CTB 57 87 55 89 / 30 20 20 10 HLN 62 93 58 93 / 30 20 20 10 BZN 53 92 51 92 / 30 20 20 10 WEY 45 82 41 83 / 30 30 30 10 DLN 55 89 52 90 / 30 20 20 10 HVR 61 93 58 94 / 30 20 20 10 LWT 58 86 54 88 / 40 30 20 10 && .TFX WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL MIDNIGHT MDT TONIGHT BEAVERHEAD... BROADWATER...CASCADE...CENTRAL AND SOUTHERN LEWIS AND CLARK... GALLATIN...JEFFERSON...MADISON...MEAGHER. && SHORT TERM...EMANUEL LONG TERM...GUSTAFSON AVIATION...MLV WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 448 AM MDT TUE JUL 10 2012 MTZ008-014-015-052>055-111200- BEAVERHEAD-CENTRAL AND SOUTHERN LEWIS AND CLARK-MADISON-JEFFERSON- BROADWATER-MEAGHER-GALLATIN- 448 AM MDT TUE JUL 10 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT RED FLAG WARNINGS HAVE BEEN ISSUED FOR MUCH OF SOUTHWEST MONTANA AND FOR SOUTHERN PORTIONS OF CENTRAL MONTANA. SCATTERED WET AND DRY THUNDERSTORMS PRODUCING STRONG AND VARIABLE WIND GUSTS ARE EXPECTED THIS AFTERNOON AND EVENING. LIGHTING STRIKES...LOW RELATIVE HUMIDITY VALUES AND STRONG THUNDERSTORMS WINDS COULD POSE A CONCERN FOR FIRE WEATHER INTERESTS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. MTZ009>013-044>051-111200- NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL-CASCADE- CHOUTEAU-TOOLE-LIBERTY-EASTERN PONDERA-BLAINE- SOUTHERN ROCKY MOUNTAIN FRONT-EASTERN TETON-JUDITH BASIN-FERGUS- 448 AM MDT TUE JUL 10 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA AND NORTH CENTRAL MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
The Missoula radar (KMSX), 199 km away, was scanning. The volume nearest the first event began at 21:31 UTC.
3 thunderstorm wind, 1 hail. Local standard time, as filed.
Outflow winds gusted to 56KT (64MPH) 6 miles SE of Jackson.
Outflow winds gusted to 51KT (59MPH) 11 miles E of Bozeman.
Quarter sized hail, measuring 1.00 inches, was reported 2 miles W of Whitehall.
A wind gust of 57KT (66MPH) was reported 6 miles N of Lakeview and was associated with thunderstorm outflow.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2012Every state in 2012This day in weather historyWarnings in Montana, July 2012
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: 398248, 398250, 398251, 398253.