A moist and unstable atmosphere became favorable for the development of linear thunderstorms across 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 moist and unstable atmosphere became favorable for the development of linear thunderstorms across 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 Jul 3, 1:26 PM MST, 1 hour 19 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 226 PM MDT TUE JUL 3 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH THURSDAY... TONIGHT THROUGH WEDNESDAY...A VIGOROUS UPPER TROUGH OVER THE NORTHERN ROCKIES IS BREAKING DOWN THE UPPER RIDGE IN PLACE OVER THE TREASURE STATE. THE ASSOCIATED SURFACE COLD FRONT HAS MADE IT BETTER THAN HALF WAY THROUGH MONTANA ALREADY THIS AFTERNOON AND IS CURRENTLY ATTEMPTING TO FORM UP A LINE OF THUNDERSTORMS OVER PHILLIPS COUNTY. WITH CAPE VALUES APPROACHING 2500 J/KG...FAVORABLE SHEAR PROFILES...AND THE FRONTAL TRIGGER...CONDITIONS ARE FAVORABLE FOR AN ORGANIZED SEVERE THUNDERSTORM OUTBREAK. THE FRONT WILL QUICKLY MOVE FROM WEST TO EAST THIS AFTERNOON AND EARLY EVENING...AND BE INTO NORTH DAKOTA BY AROUND 8 PM. THUS A SEVERE THUNDERSTORM WATCH IS IN EFFECT THROUGH 8 PM. STRONG NORTHWEST WINDS ARE EXPECTED WITH THE FRONT...AND WILL NEED TO BE MONITORED AS THEY COULD BREAK 50 MPH. GUSTY POST FRONTAL WINDS WILL CONTINUE THROUGH AROUND DAY BREAK...THUS THE LAKE WIND EXPIRATION TIME OF 4 AM LOOKS GOOD. FIRE WEATHER CONCERNS WILL ALSO CONTINUE AHEAD OF AND BEHIND THE FRONT...THUS THE RED FLAG WARNING WILL CONTINUE THROUGH 4 AM AS WELL. CLEARING WILL OCCUR LATE TONIGHT FROM WEST TO EAST...ALLOWING TEMPERATURES TO DROP INTO THE 50S AT MOST LOCATIONS. BREEZY AND MUCH COOLER TEMPERATURES ARE IN STORE FOR INDEPENDENCE DAY. WITH THAT SAID SKIES WILL BE SUNNY AS HIGH PRESSURE BUILDS IN BEHIND THE TUESDAYS SYSTEM. GILCHRIST .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... THE PERIOD BEGINS WITH SOUTHWESTERLY FLOW ALOFT WHICH WILL MAINTAIN A WARM AND SLIGHTLY UNSTABLE PATTERN WITH A SLIGHT CHANCE FOR THUNDERSTORMS EVERYDAY. THEN OVER THE WEEKEND A NEGATIVE LEANING RIDGE BUILDS INTO THE NORTHERN ROCKIES AND INTER-MOUNTAIN REGION WHICH WILL SHIFT FLOW ALOFT TO THE NORTHWEST. THIS WILL BE A WARM TO HOT PATTERN WITH A DAILY POSSIBILITY OF ISOLATED THUNDERSTORMS. NO UPPER DISTURBANCE OR FRONTAL BOUNDARY IS APPARENT IN THE MODELS...SO NO SEVERE OUTBREAK WILL OCCUR. FEW CHANGES MADE TO THE EXTENDED GRIDS. SCT PREVIOUS DISCUSSION... SOME MILD RIDGING AT THE BEGINNING OF THE EXTENDED THURSDAY EVENING ALLOWS PERIODIC BITS OF SHORTWAVE ENERGY TO PROPAGATE THROUGH THE AREA WITH AN ATTENDANT CHANCE OF THUNDERSHOWERS. AS THESE FEATURES ARE SMALL AND POORLY ANALYZED...MODELS EXPECTEDLY DISAGREE ON TIMING AND EXTENT OF PRECIP WITH THESE WAVES. HOWEVER...MODELS DO AGREE REMARKABLY WELL ON THE EXISTENCE OF THE RIDGE AND PERIODS OF SHOWER ACTIVITY THROUGH TUESDAY. RIDGE GAINS SOME STRENGTH LATE SUNDAY THROUGH TUESDAY LEADING TO A FAIRLY WARM PERIOD. HOWEVER RELATIVELY STRONG SURFACE MOISTURE CAN COMBINE WITH ANY WEAK DISTURBANCES TO GIVE SOME SLIGHT CHANCE FOR THUNDERSHOWERS EACH DAY. LACK OF ANY STRONG DYNAMICAL FORCING AND MARGINAL INSTABILITY THROUGHOUT THE EXTENDED SUGGEST ACTIVITY WILL BE NON SEVERE. WINDS THROUGH THE PERIOD WILL ALSO BE LIGHT TO MODERATE. HIGH BOUNDARY LAYER MOISTURE WILL GIVE RELATIVELY WARM LOW TEMPERATURES 5 TO 10 DEGREES ABOVE NORMAL. MARTIN && .AVIATION... WINDS CONTINUE TO PICK UP FROM THE SOUTHEAST AS A STRONG FRONT AND SURFACE TROUGH APPROACHES THE AREA FROM THE WEST. A MODERATELY UNSTABLE AIR-MASS AHEAD OF THIS FRONT WILL GENERATE SCATTERED THUNDERSTORMS. FRONTAL PASSAGE THIS AFTERNOON AND EVENING WILL BE SIGNIFICANT...WITH STRONG...40 KTS OR HIGHER...GUSTY AND SHIFTING WINDS EXPECTED...ALONG WITH SCATTERED THUNDERSTORMS...SOME POSSIBLY SEVERE. BY EVENING...STORMS MAY MERGE INTO A CONTINUOUS LINE AS FRONT APPROACHES THE NORTH DAKOTA BORDER. TIMING OF VCTS IN THE TAFS FOLLOWS THE NAM FRONTAL LOCATION TIMING. CONVECTION ALONG THE FRONT WOULD BRING THUNDERSHOWERS INTO THE VICINITY OF THE KGGW AND KOLF TERMINALS BY LATE AFTERNOON AND INTO KSDY AND KGDV SEVERAL HOURS LATER. AS THE FRONT AND ASSOCIATED THUNDERSTORMS OR SQUALL LINE MOVES EASTWARD... CONVECTION SHOULD EXIT THE KGGW AND KOLF AREAS BY LATE EVENING. SCT && .GLASGOW WATCHES/WARNINGS/ADVISORIES... RED FLAG WARNING UNTIL 4 AM MDT WEDNESDAY FOR MTZ122-136-137. LAKE WIND ADVISORY UNTIL 4 AM MDT WEDNESDAY FOR FORT PECK LAKE. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 156 PM MDT TUE JUL 3 2012 MTZ016>020-059>062-041100- CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY- DANIELS-SHERIDAN-WESTERN ROOSEVELT-NORTHERN PHILLIPS- SOUTHWEST PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT- 156 PM MDT TUE JUL 3 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A COLD FRONT WILL PUSH THROUGH NORTHEAST MONTANA THIS AFTERNOON AND EARLY EVENING. SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND LARGE HAIL ARE POSSIBLE AHEAD OF...AND WITH THIS FRONT. A SEVERE THUNDERSTORM WATCH IS IN EFFECT THROUGH 8 PM MDT. AS THE COLD FRONT SWEEPS ACROSS THE REGION DURING THE LATE AFTERNOON AND EVENING...A WIND SHIFT FROM SOUTHEAST TO NORTHWEST WILL OCCUR. VERY STRONG WINDS ARE POSSIBLE...INCLUDING WIND GUSTS IN EXCESS OF 50 MPH. A LAKE WIND ADVISORY IS IN EFFECT THROUGH 4 AM WEDNESDAY. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY 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. MTZ021>027-041100- PETROLEUM-GARFIELD-MCCONE-RICHLAND-DAWSON-PRAIRIE-WIBAUX- 156 PM MDT TUE JUL 3 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A COLD FRONT WILL PUSH THROUGH NORTHEAST MONTANA THIS AFTERNOON AND EARLY EVENING. SEVERE THUNDERSTORMS WITH DAMAGING WINDS AND LARGE HAIL ARE POSSIBLE AHEAD OF...AND WITH THIS FRONT. A SEVERE THUNDERSTORM WATCH IS IN EFFECT THROUGH 8 PM MDT. SOUTHEAST WINDS WILL BE INCREASING THROUGH THE AFTERNOON IN ADVANCE OF THE STRONG COLD FRONT. AS THE COLD FRONT SWEEPS ACROSS THE REGION...VERY STRONG WINDS ARE POSSIBLE...INCLUDING WIND GUSTS IN EXCESS OF 50 MPH. A LAKE WIND ADVISORY IS IN EFFECT THROUGH 4 AM WEDNESDAY. HOT TEMPERATURES AND LOW RELATIVE HUMIDITY COMBINED WITH THE APPROACHING COLD FRONT AND POTENTIAL THUNDERSTORMS WILL PRODUCE CRITICAL FIRE WEATHER CONDITIONS. A RED FLAG WARNING IS IN EFFECT THROUGH 4 AM WEDNESDAY. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY 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
304 PM MDT TUE JUL 3 2012
MTZ016-017-022-023-061-032200-
GARFIELD-MCCONE-PHILLIPS-VALLEY-
304 PM MDT TUE JUL 3 2012
THE NATIONAL WEATHER SERVICE IN GLASGOW HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
VALLEY COUNTY IN NORTHEAST MONTANA...
EASTERN PHILLIPS COUNTY IN NORTHEAST MONTANA...
NORTHWESTERN MCCONE COUNTY IN NORTHEAST MONTANA...
NORTHERN GARFIELD COUNTY IN NORTHEAST MONTANA...
UNTIL 400 PM MDT.
AT 300 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 6 MILES SOUTHWEST OF
HINSDALE TO 21 MILES WEST OF THE PINES REC AREA TO 8 MILES WEST OF
HELL CREEK REC AREA...AND MOVING EAST AT 35 MPH.
WIND GUSTS UP TO 50 MPH ARE EXPECTED WITH THESE STORMS...ALONG WITH
FREQUENT DANGEROUS LIGHTNING. THIS LINE OF STORMS WILL EFFECT FORT
PECK LAKE.
LOCATIONS IN THE ADVISORY INCLUDE...
FORT PECK LAKE...
HELL CREEK REC AREA...
TAMPICO...
THE PINES REC AREA...
DUCK CREEK REC AREA AND GLASGOW...
SAINT MARIE AND FORT PECK...
ROCK CREEK REC AREA AND NASHUA...
THIS STORM MAY INTENSIFY...AND A SEVERE THUNDERSTORM WATCH IS IN
EFFECT FOR THIS AREA. 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 4803 10590 4761 10612 4750 10720 4793 10733
4857 10734 4857 10721 4861 10720 4877 10632
TIME...MOT...LOC 2102Z 269DEG 31KT 4832 10714 4794 10702
4759 10704
PROTON
WEATHER.GOV/GLASGOWThe Glasgow radar (KGGW), 53 km away, was scanning. The volume nearest the first event began at 21:46 UTC.
15 hail, 14 thunderstorm wind. Local standard time, as filed.
Spotter estimated 60 mph winds and reported pea-sized hail, small tree branches downed and a power outage.
Spotter estimated 60 mph wind gusts and reported pea-sized hail and brief heavy rain.
Spotter estimated quarter-sized hail stones and wind gusts up to 50 mph. Some tree branches blown down.
Spotter measured hail up to and including quarter-sized stones.
Skywarn spotter estimated quarter-sized hail stones.
Spotter reported quarter-sized hail stones and estimated 50 mph winds gusts.
Spotter estimated quarter-sized hail stones.
Public estimated mostly dime-sized hail with some quarter-sized stones and reported heavy rain with water flowing down the streets.
Public estimated quarter-sized hail and water flowing down the streets.
Spotter reported mostly pea-sized hail with some penny-sized hail stones mixed in. Also 0.60 inches of rain in 5 minutes.
Public estimated wind gusts up to 60 mph and reported a television antenna bent in half.
Spotter estimated quarter-sized hail lasting for 5 minutes.
Spotter estimated wind gusts up to 60 mph.
Public estimated wind gusts up to 60 mph.
Public estimated quarter-sized hail stones.
Public estimated quarter-sized hail stones.
Spotter #7733 estimated wind gusts up to 65 mph.
Spotter estimated quarter-sized hail stones.
Spotter estimated wind gusts up to 60 mph.
Public reported 79 mph wind gust measured by his personal at-home station.
Spotter estimated hail up to the size of pennies.
Spotter estimated wind gusts up to 65 mph.
Spotter estimated wind gusts up to 60 mph and reported shingles blowing off their roof.
Spotter estimated winds of at least 60 mph and reported a broken 2.5-inch diameter tree limb.
Spotter estimated wind gusts up to 60 mph.
Wind gust of 65 mph measured at the Medicine Lake RAWS site.
Spotter estimated wind gusts up to 60 mph and reported a broken 6-inch diameter tree limb.
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: 400406, 400398, 400408, 401923, 400411, 401925, 400413, 400414, 401916, 401917, 400399, 401921, 401926, 401927, 401922, 400400, 401959, 401961, 401929, 401931, 401933, 401952, 400402, 401965, 401953, 401954, 401955, 401973, 401957.