Multicellular thunderstorms were in the area. One produced a quick severe gust.
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.
Multicellular thunderstorms were in the area. One produced a quick severe gust. No damages 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 Glasgow, MT wrote its last area forecast discussion before the first event at May 10, 8:13 AM MST, 3 hours 2 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 913 AM MDT SUN MAY 10 2009 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH TUESDAY... AFTERNOON SHEAR PROFILES LACKING ACROSS MUCH OF THE REGION. HOWEVER... SUFFICIENT CAPE AND LI FOR AFTERNOON PULSE SHOWERS. INVERTED V FORECAST SOUNDINGS ACROSS THE REGION SEEM INDICATE THAT SHOWERS WILL BE LIGHT AS RAIN EVAPORATES IN THE LOWER LEVELS HINTING AT MORE OF A VIRGA EVENT AND MORE RAIN IN THE HIGHER ELEVATIONS THAN ANYWHERE ELSE. WHILE RIDGING IS MOVING INTO THE REGION THERE DOES STILL APPEAR TO BE A WEAK LINGERING FRONTAL BOUNDARY ACROSS THE CENTER OF THE CWA THAT MAY STILL BE FOCAL POINT FOR SHOWER DEVELOPMENT. MOST SHOWERS SHOULD TAPER OFF AFTER SUNSET. GAH PREVIOUS SHORT TERM DISCUSSIONS.... DID A QUICK UPDATE FOR RAIN SHOWERS AFFECTING RICHLAND/EASTERN ROOSEVELT COUNTY ZONES. REST OF FORECAST LOOKED GOOD. JUST MADE CHANGE THROUGH 16Z. JAMBA TODAY AND TONIGHT...AS THE UPPER LOW MOVES SOUTHEAST DOWN THE COAST OF BRITISH COLUMBIA IT WILL AMPLIFY THE UPPER LEVEL RIDGE CURRENTLY OVER THE NORTHERN ROCKIES. EXPECT THE 850 MB TEMPERATURES ACROSS THE CWA TO RANGE BETWEEN OF 7*C TO 11*C ACROSS THE CWA. THE WAA AT THE SURFACE WILL HELP THE TEMPERATURES REACH THE MID 60S. COMBINE THIS WITH LINGERING MOISTURE...SURFACE BASED CAPE OF AROUND 600 J/KG...ACCORDING TO THE LATEST GFS...AND DESCENT LAPSE RATES WILL MAKE THUNDERSTORMS A POSSIBILITY ONCE AGAIN THIS AFTERNOON. MOST THUNDERSTORMS WILL BE ISOLATED AND THIS ACTIVITY IS NOT EXPECTED TO BE SEVERE. MONDAY INTO MONDAY NIGHT... UPPER LEVEL RIDGING WILL BEGIN TO FLATTEN OUT DURING THE DAY AS THE UPPER LOW APPROACHES THE WESTERN PART OF THE STATE. A WEAK UPPER TROFF WITH A SLIGHT NEGATIVE TILT TO IT WILL CROSS NORTHERN MONTANA DURING THE AFTERNOON. SINCE NORTHEAST MONTANA WILL STILL BE UNDER THE INFLUENCE OF A WEAK RIDGE. SURFACE BASED CAPE READINGS WILL STILL BE AROUND 800 J/KG ACROSS CENTRAL MONTANA AND GOOD LAPSE RATES...PLUS MODEL SOUNDING SHOWING AFTERNOON CONVECTIVE TEMPERATURES WILL BE REACHED...THUNDERSTORMS ARE A GOOD BET FOR MONDAY AFTERNOON. THE THUNDERSTORMS THAT FORM ON MONDAY ARE LOOKING LIKE THE PULSE TYPE BUT AN ISOLATED SEVERE STORM IS NOT OUT OF THE QUESTION. MOST OF THESE STORMS WILL FIRE ACROSS CENTRAL MONTANA AND TRACK EASTWARD INTO THE GLASGOW CWA. WESTERN ZONES HAVE A BETTER CHANCE OF SEEING THE THUNDERSTORM ACTIVITY THEN THE EASTERN ZONES. TUESDAY THE UPPER LOW WILL PUSH A SURFACE FRONT THROUGH THE AREA IN THE LATE AFTERNOON. THERE WILL BE ENOUGH INSTABILITY TO PRODUCE ISOLATED THUNDERSTORMS ALONG WITH THE EXPECTED RAIN SHOWERS. BY TUESDAY EVENING THE UPPER LOW WILL BE JUST TO THE WEST OF THE REGION ALONG WITH COLDER AIR. RAS .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... OVERALL TREND OF THE FORECAST TO REMAIN ABOUT THE SAME AS LATEST ROUND OF MODELS HAVE MORE OR LESS HELD COURSE WITH PREVIOUS. LOOKS LIKE A FAIRLY STRONG COLD FRONTAL PASSAGE ROUNDABOUT TUESDAY EVENING WITH SHOWERS AND THE THREAT FOR A FEW THUNDERSTORMS. SOME RATHER COLD AIR THEN ENTERS THE REGION FROM THE NORTH WITH THE THREAT FOR SOME SNOW SHOWERS MIXING IN WITH THE RAIN SHOWERS AFTER MIDNIGHT. WIND TO BE QUITE EXCITED AS WELL...WHICH WILL MAKE FOR A RATHER UNPLEASANTLY COOL MID-MAY NIGHT. COOL AND BREEZY DAY WEDNESDAY BEHIND THE FRONT IN NORTHWEST FLOW ALOFT WITH PERHAPS SOME INSTABILITY SHOWERS...PARTICULARLY IN THE AFTERNOON. WIND BEGINS TO SETTLE WEDNESDAY NIGHT WITH SHOWERS ENDING AND SKY CLEARING AS A WEAK TRANSITORY UPPER RIDGE MOVES ACROSS. WARMING THURSDAY WITH MAINLY ZONAL FLOW ALOFT. RIGHT NOW THURSDAY LOOKING DRY TO ME WITH NOTHING SEEN TO SPUR CONVECTION. THURSDAY NIGHT ANOTHER COLD FRONT BEGINS TO BACK INTO THE NORTHEAST CORNER OF THE CWA FROM THE NORTHEAST BUT APPEARS IS QUICKLY KICKED EAST FRIDAY IN FAST ZONAL FLOW ALOFT WHICH SWEEPS IN A SURFACE TROF FROM THE WEST ATTENDED BY WARMER AIR. A FEW SHOWERS COULD BE HAD ALONG WITH THIS SURFACE TROF AS SOME ENERGY ALOFT IN THE UPPER FLOW IS EXPECTED. WEAK UPPER TROF PASSES FRIDAY NIGHT WHICH PUSHES A WEAK COLD FRONT THRU WHICH COULD RESULT IN A FEW MORE SHOWERS. NEXT WEEKEND THE PATTERN OVER NORTH AMERICA BEGINS TO GET MORE AMPLIFIED ONCE AGAIN AS A RIDGE DEVELOPS ACROSS THE WEST AND WEAK TROF THAT MOVED THRU FRIDAY NIGHT DEEPENS AS IT MOVES INTO THE GREAT LAKES REGION. THIS LEAVES EASTERN MONTANA IN NORTHWEST FLOW ALOFT WITH AN EXPECTED SURFACE RIDGE WHICH IS NOT VERY CONDUCIVE FOR PRECIPITATION IN MOST CASES. THE SURFACE HIGH SLIPS EAST FOR MONDAY SETTING UP A GOOD EASTERLY GRADIENT FOR MONDAY. && .AVIATION... VFR CONDITIONS WILL PREVAIL THRU TONIGHT. SCATTERED TO BROKEN CLOUDS OF 5-8K FEET AGL ARE EXPECTED ONCE AGAIN TODAY WITH A FEW AFTERNOON INTO EARLY EVENING SHOWERS AROUND TOO. CLOUDS SHOULD BE CLEARING OFF TONIGHT. WIND WILL REMAIN ON THE LIGHT SIDE WITH A VERY NEBULOUS SURFACE PRESSURE PATTERN OVER THE AREA. && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && WEATHER.GOV/GLASGOW
The Glasgow radar (KGGW), 188 km away, was scanning. The volume nearest the first event began at 18:17 UTC.
1 thunderstorm wind. Local standard time, as filed.
A thunderstorm cell near Glendive collapsed and produced a single gust of 58 mph. No damages were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Montana in 2009Every state in 2009This day in weather historyWarnings in Montana, May 2009
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: 158169.