Moist, warm, and unstable surface conditions combined with favorable winds along a frontal system to create and support very slow-moving, efficient, strong to severe thunderstorms across portions of northeast Montana, south of the Missouri River.
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 GGW wrote it up.
Moist, warm, and unstable surface conditions combined with favorable winds along a frontal system to create and support very slow-moving, efficient, strong to severe thunderstorms across portions of northeast Montana, south of the Missouri River.
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 Glasgow, MT wrote its last area forecast discussion before the first event at Jun 1, 6:54 PM MST, 4 hours 5 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 754 PM MDT MON JUN 1 2015 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH WEDNESDAY... EVENING UPDATE... FOCUS FOR THE EVENING IS ON A DEVELOPED AND COLD FRONT MOVING THROUGH THE AREA AND PROHIBITING STRONG CONVECTIVE SHOWERS FROM DEVELOPING IN THE SOUTHERN AND WESTERN ZONES. A THETA-E RIDGE HAS DEVELOP ON THE SOUTHERN AND EASTERN SIDES OF THIS FRONT AND IS RUNNING UP THE YELLOWSTONE VALLEY. THIS WILL BECOME THE FOCUS FOR REMAINING STORM DEVELOPMENT AFTER MIDNIGHT IN THE CWA. WINDS AND DEWPOINT FIELDS WERE UPDATED TO INCLUDE THIS CHANGE IN FORECAST. MOST OTHER AREAS SHOULD STILL RECEIVE SOME FOR OF RAIN OVERNIGHT BUT THUNDER WILL BE LIMITED. GAH PREVIOUS SHORT TERM DISCUSSION... POTENT SYSTEM KICKS OFF FIRST WIDESPREAD SEVERE POTENTIAL FOR EASTERN MONTANA THIS EVENING. COLD FRONT STARTING TO DROP OUT OF CANADA INTO NORTH CENTRAL MONTANA WHILE THE UPPER LEVEL SHORT WAVE IS PUSHING INTO IDAHO AND THE SOUTHWEST PORTION OF THE STATE WHERE RADAR RETURNS ARE SHOWING SOME DECENT STORMS FIRING UP. MOISTURE EVIDENT WITH THETA-E ANALYSIS SHOWING A BULLSEYE OVER THE BLACK HILLS...WHERE STORMS ARE FIRING NOW IN VICINITY OF 4000 CAPE...AND THE AXIS PUSHING NORTH ALONG THE MT AND ND BORDER. PARAMETERS AND TIMING ARE SIMILAR TO THIS MORNING WITH THE BEST CHANCE OF SEVERE BEING SOUTH OF HIGHWAY 2. HAVE ACTUALLY REMOVED VERBAIGE FROM THE AREA TO THE NORTH OF HIGHWAY 2. ONE MINUTE GOES-14 IMAGERY (THANK YOU CIRA-RAMMB) HAS BEEN GREAT TO USE IN THE PAST HALF HOUR REALLY SHOWING WHERE CONVECTION IS STARTING TO FIRE THINGS ARE STARTING TO DEVELOP IN CENTRAL MONTANA. HRRR IS INDICATING CONVECTION FIRING BETWEEN MILES CITY AND GLENDIVE BY 21Z AND WHILE THE SATELLITE IMAGERY IS SHOWING CELLS TRYING TO FORM...THEY JUST AREN'T CUTTING IT YET. THE SSEO PAGE FROM SPC SHOWED THIS EARLIER TODAY GIVING CONFIDENCE THAT THINGS WILL FIRE UP OVER FERGUS COUNTY AREA AND MOVE INTO PETROLEUM AND GARFIELD COUNTIES AFTER 5-6 PM. A SPECIAL UPPER AIR RUN WAS RELEASED AT 19Z AND DATA SHOULD BE IN SHORTLY. DATA THROUGH 400 MB SHOWS THAT PWATS HAVE DECREASED BY .2 OF AN INCH SINCE THIS MORNING WITH A BIT OF A DRY SOUNDING BELOW 400 MB. THE SPEED SHEAR IS FAIRLY DECENT WITH LESS DIRECTIONAL SHEAR TO WORK WITH. WOULD ANTICIPATE MOST STORMS TO BE MULTICELLULAR/MULTICELLULAR LINE IN OUR CWA WITH A GREATER CONFIDENCE OF LARGER HAIL AND STRONG TO DAMAGING WINDS. SUPERCELLS HAVE A BETTER CHANCE IN THE SOUTHERN PORTION OF THE STATE. TONIGHT TRANSITIONS INTO A MODERATE RAINFALL EVENT...ESPECIALLY FROM KGGW WESTWARD. SOME AREAS WILL SEE IN EXCESS OF A HALF INCH OF RAIN AS THE SHORTWAVE CONTINUES IT'S PUSH INTO CANADA TONIGHT AND TUESDAY. SOUTHWEST FLOW ALOFT WILL CONTINUE TO BRING WEAK WAVES INTO THE AREA TOMORROW...BUT WITH TEMPERATURES AROUND 20 DEGREES COLDER WE LOSE THE INSTABILITY AND LIFT AND EXPECT MORE SHOWERS THAN THUNDERSTORMS THROUGH WEDNESDAY. FRANSEN .LONG TERM...WEDNESDAY NIGHT THROUGH MONDAY... LITTLE CHANGE WAS MADE TO THE LONG RANGE PERIOD WITH THE INHERITED FORECAST IN EXCELLENT SHAPE INTRODUCING A WARMING TREND AND CONTINUED UNSETTLED CONDITIONS AS A SERIES OF SHORTWAVES APPROACH EMBEDDED IN THE SOUTHWEST UPPER FLOW. AS AN UPPER RIDGE BUILDS INTO BRITISH COLUMBIA IT WILL HELP TURN THE FLOW ALOFT NORTHWESTERLY...INTRODUCING DRIER WEATHER CONDITIONS FOR SUNDAY INTO EARLY NEXT WEEK. THE ONLY REAL TWEAKS THAT WERE MADE WERE SIMPLY FOR COLLABORATION PURPOSES. MALIAWCO PREVIOUS LONG TERM DISCUSSION... BETWEEN WEDNESDAY NIGHT AND FRIDAY NIGHT... SOUTHWEST FLOW ALOFT IS EXPECTED OVER THE AREA. A SHORTWAVE RIDGE WITHIN THE SW FLOW WEDNESDAY NIGHT AND A SURFACE HIGH OVER NORTH DAKOTA WILL ALLOW FOR A PERIOD OF DRY WEATHER MAINLY OVER THE NORTHEAST HALF OF THE FORECAST AREA. WITH MOISTURE AHEAD OF A SHORTWAVE TROUGH APPROACHING FROM THE SW FOR THURSDAY...WILL NEED TO MAINTAIN A CHANCE OF SHOWERS AND THUNDERSTORMS IN THE SOUTHWEST HALF OF THE FORECAST AREA. THAT WAVE WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS TO THE ENTIRE REGION THURSDAY AND THURSDAY NIGHT. ANOTHER SHORTWAVE TROUGH ON FRIDAY WILL BRING ANOTHER CHANCE OF SHOWERS AND THUNDERSTORMS. MEANWHILE...AN UPPER TROUGH MOVING ACROSS THE CANADIAN PRAIRIES FRIDAY AND SATURDAY WILL TURN THE FLOW ALOFT OVER EASTERN MONTANA TO THE NORTHWEST ON SATURDAY. WILL HAVE YET ANOTHER CHANCE FOR SHOWERS AND THUNDERSTORMS ON SATURDAY THAT COULD LINGER INTO SUNDAY MORNING. THEN...DRIER AIR MASS INTO THE AREA. WITH SURFACE HIGH PRESSURE... SUNDAY AFTERNOON...NIGHT AND MONDAY LOOKS MAINLY DRY. FORRESTER && .AVIATION... SYNOPSIS: A COLD FRONT CONTINUES TO DROP SOUTH THROUGH THE STATE THIS EVENING KEEPING THE THUNDERSTORMS TO THE SOUTH OF THE TERMINALS THIS EVENING. OVERNIGHT SHOWERS AND A FEW THUNDERSTORMS WITH THE THUNDERSTORMS MAINLY IN THE YELLOWSTONE VALLEY. ON TUESDAY EXPECT POST FRONTAL CONDITIONS WITH LOWER CEILINGS FOR MOST LOCATIONS. FLIGHT CATEGORY: VFR WITH MVFR AFT 12Z MOVING INTO THE REGION FROM WEST TO EAST. WX: THUNDERSTORMS OVER SOUTH CENTRAL MONTANA WILL CONTINUE TO MOVE NORTHEAST UP THE YELLOWSTONE RIVER VALLEY INTO KGDV AND KSDY AFT 06Z. SHOWERS CAN BE EXPECTED ELSEWHERE STARTING AT 03Z IN THE SOUTHWEST AND SPREADING INTO KGGW AND KOLF AFT 06Z. CIGS/VSBY: VFR AND LOWERING TO MVFR CIGS AFT 12Z. OTHERWISE BRIEF PERIODS OF MVFR/IFR CAN BE EXPECTED WITH ANY THUNDERSTORMS. PROTON && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 943 AM MDT MON JUN 1 2015 MTZ016>027-059>062-021545- CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY- DANIELS-SHERIDAN-WESTERN ROOSEVELT-PETROLEUM-GARFIELD-MCCONE- RICHLAND-DAWSON-PRAIRIE-WIBAUX-NORTHERN PHILLIPS- SOUTHWEST PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT- 943 AM MDT MON JUN 1 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TODAY AND TONIGHT AN ENERGETIC PACIFIC LOW PRESSURE SYSTEM WILL CAUSE THUNDERSTORMS ACROSS THE REGION LATE THIS AFTERNOON AND TONIGHT. STRONG TO SEVERE THUNDERSTORMS ARE EXPECTED MAINLY SOUTH OF THE MISSOURI RIVER WITH DAMAGING WINDS AND LARGE HAIL BEING THE GREATEST THREATS. NORTH OF THE MISSOURI RIVER...MORE GENERAL THUNDERSTORMS AND HEAVY RAIN WILL BE THE MAIN THREATS. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY HEAVY RAIN SHOWERS ARE EXPECTED TUESDAY AFTERNOON WHILE A FEW MARGINALLY SEVERE THUNDERSTORMS WILL BE POSSIBLE SOUTH OF THE YELLOWSTONE RIVER. THUNDERSTORMS ARE IN THE FORECAST THROUGH SATURDAY. FRIDAY NIGHT COULD HOLD ANOTHER ROUND OF WIDESPREAD SEVERE WEATHER. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE GLASGOW MT
1152 PM MDT MON JUN 1 2015
MTZ025>027-020630-
DAWSON-PRAIRIE-WIBAUX-
1152 PM MDT MON JUN 1 2015
THE NATIONAL WEATHER SERVICE IN GLASGOW HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
SOUTHERN WIBAUX COUNTY IN NORTHEAST MONTANA...
EASTERN PRAIRIE COUNTY IN NORTHEAST MONTANA...
SOUTHEASTERN DAWSON COUNTY IN NORTHEAST MONTANA...
UNTIL 1230 AM MDT.
AT 1147 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 22 MILES SOUTHWEST OF WIBAUX...MOVING NORTHEAST
AT 20 MPH.
HAIL UP TO THE SIZE OF PENNIES AND WIND GUSTS UP TO 50 MPH ARE
EXPECTED WITH THIS STORM.
LOCATIONS IN THE ADVISORY INCLUDE...
RURAL AREAS OF SOUTHWESTERN WIBAUX COUNTY...
RURAL AREAS OF SOUTHEASTERN DAWSON COUNTY...
RURAL AREAS OF SOUTHERN WIBAUX COUNTY...
RURAL AREAS OF CENTRAL WIBAUX COUNTY...
LAT...LON 4663 10405 4664 10436 4666 10437 4667 10442
4668 10443 4668 10457 4686 10477 4703 10435
4702 10404 4664 10404
TIME...MOT...LOC 0552Z 238DEG 17KT 4678 10449
GAH
WEATHER.GOV/GLASGOWThe Glasgow radar (KGGW), 228 km away, was scanning. The volume nearest the first event began at 05:57 UTC.
1 thunderstorm wind, 1 hail, 1 flash flood. Local standard time, as filed.
Trained Spotter in the town of Wibaux estimated 60 mph wind gusts from a thunderstorm just before midnight.
Trained Spotter in the town of Wibaux reported nickel-sized hail.
Richland County dispatch reported cars stalled, floating, and flowing along city streets in Sidney. Rainfall rates during the early morning hours were 1-2 inches per hour. By mid-day, around 2.5 inches of rain had accumulated.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2015Every state in 2015This day in weather historyWarnings in Montana, June 2015
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: 571441, 571442, 571443.