A disturbance aloft and an unstable airmass resulted in severe thunderstorms developing over portions of North Central Montana. Wind gusts in excess of 60 mph were reported.
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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.
A disturbance aloft and an unstable airmass resulted in severe thunderstorms developing over portions of North Central Montana. Wind gusts in excess of 60 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 Jun 28, 2:14 PM MST, 1 hour 1 minute earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GREAT FALLS MT 314 PM MDT TUE JUN 28 2011 .DISCUSSION... THIS AFTERNOON THROUGH THURSDAY EVENING...CENTRAL...NORTHCENTRAL AND SOUTHWEST MT ENTERING AN ACTIVE WEATHER PERIOD FOR THE NEXT 36 HOURS OR SO AS UNSTABLE CONDITIONS AND PLENTIFUL MOISTURE WILL PRODUCE PERIODS OF THUNDERSTORMS THIS AFTN/EVE AND AGAIN TOMORROW. HIGH PRESSURE RIDGE OVER THE NORTHERN ROCKIES HAS BEEN WEAKENING AND DRIFTING EAST WHILE DEEP UPPER LEVEL TROF OFF THE CALIF COAST BEGINS TO TURN INLAND. LEADING EDGE OF MOISTURE AND A EMBEDDED SHORTWAVE FROM THE PACIFIC SYSTEM IS CURRENTLY ALONG THE MT/ID BORDER AND BEGINNING TO FIRE THUNDERSTORMS ALONG THE BITTERROOT MTNS. EXPECT THESE STORMS WILL SPREAD EASTWARD INTO CENTRAL AND SOUTHWEST COUNTIES OVER THE NEXT SEVERAL HOURS...WITH A FEW BRIEFLY REACHING SEVERE STATUS...WITH HAIL AROUND 1 INCH IN DIAMETER AND WINDS GUSTING TO AROUND 60 MPH. MAIN CONVECTIVE ACTIVITY WILL BE AROUND FERGUS/BLAINE COUNTIES TONIGHT BEFORE EXITING INTO ERN MT AFTER MIDNIGHT. REGION WILL SEE A BRIEF BREAK FROM PRECIPITATION DURING THE MORNING HOURS ON WED...BUT AS THE PACIFIC SYSTEM MOVES INTO NEVADA...MOISTURE AND INSTABILITY WILL REBUILD OVER OUR AREA SETTING OFF ANOTHER ROUND OF STRONG TO SEVERE STORMS TOMORROW AFTN/EVE. FORECAST MODELS IN GOOD AGREEMENT THAT THE UPPER TROF WILL BE SLOW TO CLEAR THE AREA SO HAVE INCREASED CHANCES OF PRECIP OVER SOUTHWEST MT WHERE RAIN SHOWERS WILL LINGER THRU THURS AFTN. WARM TEMPS EXPECTED AGAIN TOMORROW BEFORE THE STORMS ARRIVE...WITH 80S AND 90S ACROSS THE VALLEYS/PLAINS. SHARPLY COOLER TEMPS ARRIVE ON THURS AS CANADIAN AIRMASS ARRIVES BEHIND THE UPPER TROF...WITH MOST LOCATIONS ONLY REACHING THE MID 60S TO LOW 70S. WARANAUSKAS THURSDAY NIGHT THROUGH TUESDAY...LINGERING THUNDERSTORMS ARE EXPECTED TO END THURSDAY NIGHT AND MAINLY THURSDAY EVENING AS AN UPPER TROUGH MOVES EAST. THEN FRIDAY THROUGH SUNDAY MODELS POINT TO A GENERALLY DRY WESTERLY FLOW ALOFT. ON THE FOURTH OF JULY THE GFS MODEL DEVELOPS AN UPPER RIDGE OVER IDAHO AND WESTERN MONTANA WHILE THE ECMWF MODEL CONTINUES THE WESTERLY FLOW ALOFT. THEN ON TUESDAY THE GFS MODEL MOVES THE UPPER RIDGE OVER THE FORECAST AREA. THE ECMWF MODEL ON THE OTHER HAND DEVELOPS AN UPPER RIDGE OVER THE PACIFIC NORTHWEST AND WESTERN CANADA WITH NORTHWEST FLOW ALOFT FARTHER EAST. THIS NORTHWEST FLOW USHERS IN A COOLER AIRMASS ACCORDING TO THE ECMWF WHILE THE GFS CONTINUES WITH THE WARMER AIRMASS. OTHER GUIDANCE SEEMS MORE IN LINE WITH THE GFS THOUGH THEY ARE WEAKER WITH THE UPPER RIDGE. SO FOR THIS FORECAST HAVE LEANED TOWARDS THE GFS SOLUTION. ALL IN ALL EXPECT A RELATIVELY DRY AND WARM PERIOD. WILL GO WITH A SLIGHT CHANCE OF THUNDERSTORMS OVER FAR SOUTHWEST MONTANA ON SUNDAY AND OVER ALL OF SOUTHWEST MONTANA ON THE FOURTH OF JULY. DUE TO MODEL UNCERTAINTIES WILL GO WITH A MORE WIDESPREAD SLIGHT CHANCE OF THUNDERSTORMS ON TUESDAY. INHERITED WARMING TREND FROM FRIDAY INTO SUNDAY STILL LOOKS GOOD AND DID NOT MAKE ANY BIG CHANGES WITH RESPECT TO FORECAST TEMPERATURES. BLANK && .AVIATION... UPDATED 1100Z. VFR CONDITIONS ARE LIKELY. EXPECT THIN CIRRUS CLOUDS INTO THE AFTERNOON. AFTER 3 PM EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO DEVELOP IN THE KBTM AREA THEN SPREAD NORTHEAST...AFFECTING KHLN BEFORE 00Z AND KGTF AROUND 00Z. THERE IS SOME QUESTION IF THE THUNDERSTORMS WILL REACH KCTB AND KHVR THIS EVENING. IN THE TAFS DID NOT MENTION THUNDERSTORMS AT THOSE TWO LOCATIONS BUT DO NOT BE SURPRISED IF A THUNDERSTORM AFFECTS THOSE AIRPORTS OR GETS IN THE VICINITY. WITH THE THUNDERSTORMS THERE WILL BE A THREAT OF GUSTY WINDS OF 30 TO 40 KNOTS. CONFIDENCE IN FORECAST WIND DIRECTIONS TODAY IN THE TAFS IS A LITTLE BELOW AVERAGE. BLANK && .HYDROLOGY... HIGH TEMPERATURES WILL WARM TO NEAR TYPICAL SEASONAL VALUES THIS WEEK...REMAINING WARM THROUGH WED. THIS WILL LEAD TO AN INCREASE IN SNOW MELT DURING THE EARLY/MIDDLE PART OF THE WEEK. RESERVOIRS ACROSS THE AREA REMAIN NEAR CAPACITY AND AS A RESULT MAY INCREASE THE AMOUNT OF WATER RELEASED AND SUBSEQUENT WATER LEVELS. IN ADDITION...STRONG TO SEVERE THUNDERSTORMS...SOME WITH HEAVY RAINFALL...ARE POSSIBLE WEDNESDAY. ANY RAIN FALLING ON TOP OF SNOW WILL LEAD TO FASTER SNOW MELT AND RISING WATER LEVELS. && .PRELIMINARY POINT TEMPS/POPS... GTF 54 85 51 67 / 30 60 20 20 CTB 57 80 52 64 / 20 40 20 20 HLN 53 84 51 68 / 30 60 30 20 BZN 49 85 49 70 / 10 40 40 40 WEY 38 74 38 62 / 10 30 40 50 DLN 50 81 46 69 / 10 50 30 30 HVR 56 86 52 73 / 20 40 30 20 LWT 53 86 48 68 / 30 40 40 30 && .TFX WATCHES/WARNINGS/ADVISORIES... FLOOD HIGHLIGHTS REMAIN IN EFFECT UNTIL FURTHER NOTICE. && SHORT TERM...WARANAUSKAS LONG TERM...BLANK AVIATION...WILLIAMSON DC WEATHER.GOV/GREATFALLS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GREAT FALLS MT 347 AM MDT TUE JUN 28 2011 MTZ008-012-015-053-055-291000- BEAVERHEAD-CASCADE-MADISON-BROADWATER-GALLATIN- 347 AM MDT TUE JUN 28 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT FLOOD HIGHLIGHTS REMAIN IN EFFECT ACROSS PORTIONS OF THE REGION. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY FLOOD HIGHLIGHTS WILL REMAIN IN EFFECT ACROSS PORTIONS OF THE REGION UNTIL FURTHER NOTICE. STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO IMPACT THE AREA ON WEDNESDAY AFTERNOON AND EVENING. LARGE HAIL AND GUSTY OUTFLOW WINDS IN EXCESS OF 50 MPH WILL BE POSSIBLE WITH SOME OF THESE STORMS. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO SEND FLOODING REPORTS TO THE NATIONAL WEATHER SERVICE IN GREAT FALLS. SPOTTER ACTIVATION WILL LIKELY BE NEEDED WEDNESDAY FOR POTENTIAL SEVERE WEATHER. MTZ009>011-013-014-044>052-054-291000- NORTHERN ROCKY MOUNTAIN FRONT-EASTERN GLACIER-HILL-CHOUTEAU- CENTRAL AND SOUTHERN LEWIS AND CLARK-TOOLE-LIBERTY- EASTERN PONDERA-BLAINE-SOUTHERN ROCKY MOUNTAIN FRONT- EASTERN TETON-JUDITH BASIN-FERGUS-JEFFERSON-MEAGHER- 347 AM MDT TUE JUN 28 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL MONTANA...NORTH CENTRAL MONTANA AND SOUTHWEST MONTANA. .DAY ONE...TODAY AND TONIGHT THE PROBABILITY OF WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED TO IMPACT THE AREA ON WEDNESDAY AFTERNOON AND EVENING. LARGE HAIL AND GUSTY OUTFLOW WINDS IN EXCESS OF 50 MPH WILL BE POSSIBLE WITH SOME OF THESE STORMS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL LIKELY BE NEEDED WEDNESDAY FOR POTENTIAL SEVERE WEATHER.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GREAT FALLS MT
308 PM MDT TUE JUN 28 2011
MTZ008-282145-
BEAVERHEAD MT-
308 PM MDT TUE JUN 28 2011
...SIGNIFICANT WEATHER ADVISORY FOR NORTHERN BEAVERHEAD COUNTY UNTIL
345 PM MDT...
AT 306 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING A
STRONG THUNDERSTORM 11 MILES EAST OF WISDOM...OR 37 MILES SOUTH OF
ANACONDA...MOVING NORTH AT 25 MPH.
HAIL UP TO ONE-HALF INCH IN DIAMETER AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM...ALONG WITH HEAVY RAIN.
* LOCATIONS IMPACTED INCLUDE...
RURAL NORTHERN BEAVERHEAD COUNTY...
THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.
LAT...LON 4583 11328 4589 11321 4589 11318 4589 11310
4586 11307 4581 11297 4553 11315 4559 11339
TIME...MOT...LOC 2108Z 200DEG 23KT 4565 11322
COULSTONThe Great Falls radar (KTFX), 9 km away, was scanning. The volume nearest the first event began at 22:16 UTC.
6 thunderstorm wind. Local standard time, as filed.
A thunderstorm produced a wind gust to 60 mph at Great Falls. Power poles were reported down in the city and tree limbs 2 to 3 inches in diameter were snapped.
A thunderstorm produced a wind gust to 68 mph was reported at Cascade 5S.
A thunderstorm produced a wind gust to 60 mph at Cascade.
A thunderstorm produced a wind gust to 60 mph at Floweree 4NNW. Tree branches were reported down.
A thunderstorm produced a wind gust to 65 mph at Loma 1N.
A thunderstorm produced a wind gust to 70 mph at Chinook 10S.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2011Every state in 2011This day in weather historyWarnings in Montana, June 2011
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: 316983, 316999, 317000, 317017, 317001, 317002.