A moderately unstable atmosphere and a stalled surface frontal boundary allowed some strong to severe thunderstorms to develop 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 moderately unstable atmosphere and a stalled surface frontal boundary allowed some strong to severe thunderstorms to develop 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 Jul 4, 1:32 PM MST, 28 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 232 PM MDT THU JUL 4 2013 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH SATURDAY... AN UPPER SHORTWAVE TROUGH SWINGING ACROSS THE PAC-NW IS INDUCING AN AREA OF CONVECTION IN CENTRAL MT THAT WILL DRIFT INTO THE WESTERN COUNTIES OF NORTHEAST MONTANA THIS EVENING. MODERATELY UNSTABLE CONDITIONS THERE COULD DEVELOP A FEW STRONG THUNDERSTORMS. THEREFORE...SPREAD SCT POPS INTO THOSE AREAS AND ADDED MENTION OF HAIL AND GUSTY WINDS. MORE GENERAL THUNDERSTORMS WITH RAIN SHOWERS SHOULD CONTINUE ACROSS THE AREA OVERNIGHT AS A WEAK COLD FRONT AND LEE SURFACE TROUGH MARCH OVER THE AREA. FRIDAY...FLOW ALOFT BECOMES SOUTHWEST WITH CONTINUED INSTABILITY LEADING TO MORE THUNDERSTORMS. WITH MORE WARM AIR BEING PUMPED INTO THE AREA...ALONG WITH ADDITIONAL MOISTURE...EXPECT ANOTHER WARM DAY. FRIDAY NIGHT AND SATURDAY...THE UPPER TROUGH AND A WEAK EMBEDDED DISTURBANCE MOVE INTO MONTANA TO BRING A CONTINUATION OF CONVECTION AND ADDED QPF. THE WEAK TROUGHINESS AND CLOUDINESS WILL BRING A SLIGHT COOLING TO MORE SEASONAL HIGHS. EXCEPT NEAR THUNDERSTORMS...WIND WILL NOT BE MUCH OF AN ISSUE THROUGH THE SHORT TERM. IN ADDITION...SPC KEEPS NEMONT WITHIN THEIR CONVECTIVE OUTLOOK BOUNDARY THROUGHOUT THE SHORT TERM FOR GENERAL THUNDERSTORMS...WITH SEE TEXT NOTES CONCERNING THE POSSIBILITY OF A FEW STRONG MARGINAL SEVERE STORMS. SCT .LONG TERM...SATURDAY NIGHT THROUGH THURSDAY... NO MAJOR CHANGES TO THE GOING FORECAST. WESTERN RIDGE IS SUPPRESSED AS SHORTWAVES PUSH THROUGH SOUTHWEST CANADA. FAIRLY TYPICAL FOR THE BEGINNING OF JULY WITH WARM TEMPERATURES AND CHANCES OF THUNDERSTORMS. EBERT PREVIOUS LONG TERM DISCUSSION...THE EXTENDED PERIOD WILL START WITH ZONAL TO SLIGHTLY SOUTHWEST FLOW WHICH WILL CONTINUE THROUGH MOST OF THE PERIOD. THEN THE RIDGE IS EXPECTED TO BUILD IN TOWARDS THE END OF THE PERIOD. THE OVERALL PATTERN IS ONE THAT IS TYPICAL FOR THIS TIME OF YEAR...MAYBE A LITTLE MORE ACTIVE. THE MODEL RUNS ARE PUSHING SYSTEMS INTO THE CANADIAN PRAIRIES MORE THAN TRACKING THEM THROUGH CENTRAL MONTANA. WHICH LEADS TO FAIRLY GOOD CONFIDENCE ON THE FORECAST. TEMPERATURES SEEM TO BE FAIRLY NORMAL THROUGH THE PERIOD WITH A WARM UP TOWARDS THE VERY END. PROTON && .AVIATION... VFR WITH LIGHT WINDS. SCATTERED THUNDERSTORMS ARE POSSIBLE OVERNIGHT. && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 321 AM MDT THU JUL 4 2013 MTZ016>027-059>062-050930- 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- 321 AM MDT THU JUL 4 2013 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TODAY AND TONIGHT THUNDERSTORMS ARE EXPECTED TO FORM OVER THE HIGHER ELEVATIONS OF CENTRAL MONTANA TODAY AND DRIFT EASTWARD AND EMERGE OVER THE HIGH PLAINS OF NORTHEAST MONTANA THIS AFTERNOON AND EVENING. GUSTY WINDS...CLOUD TO GROUND LIGHTNING...AND SMALL HAIL WILL BE THE MAIN THREATS NEAR THE STRONGER STORMS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A RE-ENFORCING UPPER LEVEL TROUGH FROM THE CANADIAN ROCKIES WILL ALLOW MARGINALLY STRONG THUNDERSTORMS TO DEVELOP AND SPREAD OVER MOST OF NORTHEAST MONTANA FRIDAY AFTERNOON AND EVENING. GUSTY WINDS...CLOUD TO GROUND LIGHTNING...AND SMALL HAIL WILL BE THE MAIN THREATS NEAR THE STRONGER STORMS. .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
215 PM MDT THU JUL 4 2013
MTZ021-042130-
PETROLEUM-
215 PM MDT THU JUL 4 2013
THE NATIONAL WEATHER SERVICE IN GLASGOW HAS ISSUED A
SIGNIFICANT WEATHER ADVISORY FOR...
SOUTHWESTERN PETROLEUM COUNTY IN NORTHEAST MONTANA...
UNTIL 330 PM MDT.
AT 208 PM MDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM 10 MILES SOUTHEAST OF GRASS RANGE...MOVING EAST
AT 10 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 IN THE ADVISORY INCLUDE...
FLATWILLOW...
LAT...LON 4685 10862 4707 10862 4707 10860 4676 10803
4674 10811 4675 10819 4674 10861 4676 10864
4683 10864
TIME...MOT...LOC 2015Z 291DEG 8KT 4691 10864
RAE
WEATHER.GOV/GLASGOWThe Billings radar (KBLX), 105 km away, was scanning. The volume nearest the first event began at 20:59 UTC.
4 hail, 1 flash flood. Local standard time, as filed.
Public reported mostly pea-sized hail mixed with some quarter and half-dollar sized hail. Brief, heavy rain.
Trained spotter reported penny-sized hail with rain.
NWS Employee reported walnut-sized hail.
Trained spotter reported pea-sized and quarter-sized hail with heavy rain and 35-45 mph wind gusts.
McCone County dispatch office reported flash flooding from strong thunderstorms. Water quickly flowing down the street and up over the sidewalks, approaching the doorways.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2013Every state in 2013This day in weather historyWarnings in Montana, July 2013
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: 468932, 468933, 468934, 468937, 468931.