A marginally unstable atmosphere combined with a weak upper-level disturbance to form some strong thunderstorms, a few of which became severe across portions of northeast Montana.
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.
A marginally unstable atmosphere combined with a weak upper-level disturbance to form some strong thunderstorms, a few of which became severe across portions of northeast Montana.
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 Aug 30, 1:27 PM MST, 5 hours 3 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 227 PM MDT SUN AUG 30 2015 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY... AN UPPER LEVEL TROUGH WILL MOVE ACROSS THE DIVIDE TONIGHT THAT WILL SEND ANOTHER...STRONGER...COLD FRONT THROUGH NORTHEAST MONTANA. TIMING PUTS THE FRONT HALFWAY THROUGH THE CWA AT 06Z AND ALL THE WAY THROUGH BY 12Z. SOME PACIFIC MOISTURE HAS BEEN ENTRAINED IN THE SOUTHWEST FLOW...SO THIS COULD BRING WETTING RAINS TONIGHT...ALONG WITH THUNDER. MODELS ARE SHOWING STRONG SHEAR PROFILES...THAT ALONG WITH SOME AFTERNOON HEATING HAS PROMPTED SPC TO PLACE OUR WESTERN COUNTIES IN A MARGINAL RISK...FOR STRONG WIND AND POSSIBLE HAIL THIS EVENING. SMOKE IS THE OTHER ISSUE RIGHT NOW. THE TROUGH MOVING THROUGH...ALONG WITH ASSOCIATED LIFT IS TENDING TO CLEAR THE SMOKE...FOR NOW. THEREFORE CANCELLED THE DENSE SMOKE ADVISORY. MONDAY...THE UPPER TROUGH MOVES OFF TO THE EAST AND ALL WINDS...SURFACE TO ALOFT...WILL BECOME WESTERLY. SURFACE WIND BEGINS TO RELAX AS THE SURFACE LOW MOVES FARTHER EAST. THE COOLER AIR BEHIND THE COLD FRONT WILL DRIVE TEMPERATURE BACK TO NORMAL. TUESDAY...FLOW ALOFT BACKS AROUND TO THE SOUTHWEST AND THE THERMAL BOUNDARY FIRMS UP WITH NORTHEAST MONTANA BEGINS TO SEE HOT AIR DRIFTING BACK INTO THE AREA. THIS WILL DRIVE TEMPERATURES BACK ABOVE NORMAL. MAIN FORECAST PROBLEM FOR THE NEXT FEW DAYS WILL BE THE SMOKE. SHOWERS AND SOUTHWEST FLOW TODAY CLEARED SOME OF THE SMOKE OUT OF THE AIR...BUT WITH WESTERLY FLOW AND SUBSIDENCE ON MONDAY EXPECT THE SMOKE WILL RETURN. THIS AFTERNOON VISIBILITY HAS IMPROVED EVERYWHERE. IF SMOKE BECOMES DENSE AGAIN THE DENSE SMOKE ADVISORY WILL BE REISSUED. SCT .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... MODELS CONTINUE THEIR AGREEMENT ON A SYSTEM LATE THIS WEEK WITH A GOOD CHANCE OF SHOWERS AND COOLER TEMPERATURES. IN COORDINATION WITH NEIGHBORING OFFICE TO OUR WEST...CONTINUED TREND OF RAISING POPS AND LOWERING TEMPERATURES SLIGHTLY. REST OF CHANGES WERE MINOR. TFJ PREVIOUS DISCUSSION... SYNOPTIC SET UP... LONG RANGE BEGINS WITH HOT HIGH PRESSURE OVER THE DESERTS SOUTHWEST AND FOUR CORNERS AND A WARM RIDGE RUNNING OUT OF COLORADO AND THEN MOVING NORTH UP THE HIGH PLAINS INTO EASTERN MONTANA. A CLOSED LOW SETS OVER THE SOUTHERN COAST OF BRITISH COLUMBIA AND IS GENERATING UNSTABLE SOUTHWEST FLOW ACROSS NORTHERN CALIFORNIA THROUGH WESTERN MONTANA AND SOUTHERN SASKATCHEWAN. TUESDAY NIGHT THROUGH WEDNESDAY NIGHT... RIDGE WILL HAVE THE MOST INFLUENCE DURING THIS TIME. EXPECT WARM TEMPERATURES WAITING FOR AN UPPER LEVEL FRONT TO MOVE IN AND BEGIN MIXING DOWNWARD WEDNESDAY EVENING. THURSDAY THROUGH FRIDAY... UNSTABLE SOUTHWEST FLOW WILL MOVE OVER THE AREA. CHANCES FOR A SHOWERS AND THUNDERSTORMS WILL INCREASE DURING THIS TIME... BUT... MODELS HAVE NOT ESTABLISHED A SINGLE JET OR WAVE FEATURES TO LATCH ONTO AND EACH MODEL IS A LITTLE DIFFERENT IN WHERE THE ISOLATED SHOWERS WILL FORM OR MOVE. FRIDAY NIGHT TO SATURDAY NIGHT... SYNOPTIC TROUGH BASE TO THE WEST MOVES INTO WESTERN MONTANA. THIS WILL INCREASE CHANCES FOR RAIN SHOWERS AND FURTHER DROP TEMPERATURES ACROSS THE REGION. SUNDAY ONWARD... MODELS BEGIN HAVING TROUBLE WITH SYNOPTIC FEATURES HERE... BUT THE GENERAL OUTCOME IS FOR THE BASE OF THE TROUGH TO BE OVER NORTHEAST MONTANA OR HAVE JUST MOVED SOUTHEAST. EXPECT TEMPERATURES TO BE AT THEIR LOWEST DURING THIS TIME AND CHANCES FOR SHOWERS AND THUNDERSTORMS TO BACK OFF SLIGHTLY. GAH && .AVIATION... FLIGHT CATEGORY: VFR ANOTHER ROUND OF SHOWERS AND ISOLATED THUNDERSTORMS ARE TO MOVE IN FROM THE SW THIS EVENING MAINLY AFFECTING THE KGGW AREA. VISIBILITIES MAY DROP BELOW VFR IN HEAVIER SHOWERS. NORTHWEST WINDS WILL INCREASE TONIGHT WITH ANOTHER COLD FRONTAL PASSAGE. GUSTS TO 25 KTS ARE POSSIBLE. TFJ && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 104 PM MDT SUN AUG 30 2015 MTZ016>027-059>062-311100- 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- 104 PM MDT SUN AUG 30 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .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 458 PM MDT SUN AUG 30 2015 MTZ016-017-021-022-310000- CENTRAL AND SOUTHERN VALLEY MT-CENTRAL AND SOUTHEAST PHILLIPS MT- PETROLEUM MT-GARFIELD MT- 458 PM MDT SUN AUG 30 2015 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN VALLEY...WEST CENTRAL GARFIELD...NORTHEASTERN PETROLEUM AND SOUTHEASTERN PHILLIPS COUNTIES UNTIL 600 PM MDT... AT 457 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 11 MILES SOUTHEAST OF CROOKED CREEK REC AREA...OR 38 MILES NORTHEAST OF WINNETT...MOVING NORTHEAST AT 35 MPH. HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... U L BEND REC AREA...CROOKED CREEK REC AREA...BRUSETT...DEVILS CREEK REC AREA...CAT CREEK AND STEVE FORK. PRECAUTIONARY/PREPAREDNESS ACTIONS... FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE SHELTER INSIDE A BUILDING OR VEHICLE. IF ON OR NEAR THE WEST END OF FORT PECK LAKE...GET OUT OF THE WATER AND MOVE INDOORS OR INSIDE A VEHICLE. REMEMBER...LIGHTNING CAN STRIKE OUT TO 15 MILES FROM THE PARENT THUNDERSTORM. IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. MOVE TO SAFE SHELTER NOW. DO NOT BE CAUGHT ON THE WATER IN A THUNDERSTORM. && LAT...LON 4700 10810 4762 10812 4773 10736 4721 10707 TIME...MOT...LOC 2257Z 242DEG 32KT 4735 10772 PROTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GLASGOW MT 525 PM MDT SUN AUG 30 2015 MTZ016-017-022-023-310030- CENTRAL AND SOUTHERN VALLEY MT-CENTRAL AND SOUTHEAST PHILLIPS MT- GARFIELD MT-MCCONE MT- 525 PM MDT SUN AUG 30 2015 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN VALLEY... NORTHWESTERN MCCONE...CENTRAL GARFIELD AND SOUTHEASTERN PHILLIPS COUNTIES UNTIL 630 PM MDT... AT 524 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 8 MILES NORTH OF BRUSETT...OR 21 MILES NORTHWEST OF JORDAN...MOVING NORTHEAST AT 55 MPH. HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... JORDAN...FORT PECK...THE PINES REC AREA...DUCK CREEK REC AREA... NELSON CREEK REC AREA...ROCK CREEK REC AREA...BRUSETT...HELL CREEK REC AREA...FORT PECK MARINA...VAN NORMAN...HAXBY AND PARK GROVE. PRECAUTIONARY/PREPAREDNESS ACTIONS... FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM. LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE SHELTER INSIDE A BUILDING OR VEHICLE. IF ON OR NEAR FORT PECK LAKE...GET OUT OF THE WATER AND MOVE INDOORS OR INSIDE A VEHICLE. REMEMBER...LIGHTNING CAN STRIKE OUT TO 15 MILES FROM THE PARENT THUNDERSTORM. IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE STRUCK BY LIGHTNING. MOVE TO SAFE SHELTER NOW. DO NOT BE CAUGHT ON THE WATER IN A THUNDERSTORM. && LAT...LON 4728 10739 4779 10761 4810 10626 4736 10604 TIME...MOT...LOC 2324Z 240DEG 49KT 4755 10722 PROTON
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE GLASGOW MT 640 PM MDT SUN AUG 30 2015 MTZ016-017-021-022-310145- CENTRAL AND SOUTHERN VALLEY MT-CENTRAL AND SOUTHEAST PHILLIPS MT- PETROLEUM MT-GARFIELD MT- 640 PM MDT SUN AUG 30 2015 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN VALLEY...WEST CENTRAL GARFIELD...NORTHEASTERN PETROLEUM AND SOUTHEASTERN PHILLIPS COUNTIES UNTIL 745 PM MDT... AT 639 PM MDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM 14 MILES SOUTH OF CROOKED CREEK REC AREA...OR 24 MILES NORTHEAST OF WINNETT...MOVING NORTHEAST AT 55 MPH. HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM. LOCATIONS IMPACTED INCLUDE... JORDAN...U L BEND REC AREA...CROOKED CREEK REC AREA...BRUSETT...HELL CREEK REC AREA AND STEVE FORK. PRECAUTIONARY/PREPAREDNESS ACTIONS... TO REPORT SEVERE WEATHER...CONTACT YOUR NEAREST LAW ENFORCEMENT AGENCY. THEY WILL RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE OFFICE IN GLASGOW. && LAT...LON 4711 10799 4737 10816 4791 10703 4723 10660 TIME...MOT...LOC 0039Z 240DEG 49KT 4721 10794 GAH
The Glasgow radar (KGGW), 99 km away, was scanning. The volume nearest the first event began at 01:29 UTC.
3 thunderstorm wind. Local standard time, as filed.
Trained spotter reported winds gusting up to 60 mph.
Trained spotter reported a metal grain building blown down and scattered. Windows also reported broken.
Trained spotter reported 65 mph wind gusts.
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, August 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: 597882, 597881, 597883.