A large and expanding upper level disturbance swept southward from the Canadian Rockies bringing heavy rain and heavy snow to portions of northeast Montana. Just enough atmospheric mixing was present to allow some higher wind speeds to mix down to the surface.
Every event with a place to put it; 2 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 large and expanding upper level disturbance swept southward from the Canadian Rockies bringing heavy rain and heavy snow to portions of northeast Montana. Just enough atmospheric mixing was present to allow some higher wind speeds to mix down to the surface.
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 Feb 21, 9:23 AM MST, 3 hours 37 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GLASGOW MT 923 AM MST TUE FEB 21 2012 .SHORT TERM...FOR NORTHEAST MONTANA...TODAY THROUGH THURSDAY... GOING FORECAST APPEARS TO BE IN GOOD SHAPE THROUGH THE NEXT 12-18 HOURS. A WEAK TROUGH OR WARM FRONT LOOKS TO MOVE EAST THROUGH THE AREA AND POSSIBLY TRIGGER A SPRINKLE OR FLURRY WITH IT. GOING FORECAST HAS MAINLY SLIGHT CHANCE POPS FOR THIS AND LOOKS GOOD. OTHERWISE...NOT MUCH WAS TWEAKED AT THIS TIME. JAMBA PREVIOUS DISCUSSION... THE BASE OF THE UPPER TROUGH HAS MOVED EAST OF MONTANA...WHICH HAS SHIFTED WINDS ALOFT TO THE NORTHWEST. THE STATIONARY BOUNDARY WHICH STRADLES THE DIVIDE WILL BEGIN TO ADVANCE EAST AS A WARM FRONT. OVERRUNNING MOISTURE IN THE NORTHWEST FLOW ALONG THIS BOUNDARY WILL MOVE LOW TO MID LEVEL OVERCAST ACROSS EASTERN MONTANA LATER TODAY. INHERITED SMALL POPS STILL LOOK GOOD FOR LIGHT MIXED PRECIPITATION IN THE AFTERNOON AND EVENING. THICKNESS HEIGHTS INCREASE FROM AROUND 525DM AT 00Z TUESDAY TO 535DM AT 00Z WEDNESDAY. THEREFORE EXPECT HIGHS TODAY TO BE A BIT WARM THAN MONDAY. TONIGHT...THE WARM FRONTAL BOUNDARY BECOME MORE DISTINCT ACROSS NEMONT AFTER MIDNIGHT. AN UPPER LEVEL SHORTWAVE DISTURBANCE... CURRENTLY SOUTH OF THE ALASKA PENINSULA...WILL INTRODUCE PACIFIC MOISTURE INTO THE UPPER FLOW. THIS INCREASED OVERRUNNING MOISTURE INTRODUCES A SUBSTANTIAL AMOUNT OF QPF ALONG THE FRONT. THE GFS...NAM AND EC ALL AGREE WITH AROUND 0.10 TO 0.15 INCH OF QPF OVER THE WESTERN ZONES FROM 06Z-12Z. THERE ARE SOME DIFFERENCES IN TEMPERATURE PROFILES. BUT GENERALLY THE PRECIPITATION SHOULD BE MOSTLY RAIN IN THE SOUTHWEST AND MOSTLY SNOW IN THE NORTHWEST. MINIMUM TEMPERATURES WILL BE TRICKY WITH THICKNESS HEIGHTS RAMPING UP TO 545DM BY 12Z WEDNESDAY. THERE WILL NOT BE MUCH FALL OFF OF TEMPERATURES OVERNIGHT IN THE WEST. WEDNESDAY...AS THE WARM FRONT MOVES EAST ACROSS NEMONT A COLD FRONT...ASSOCIATED WITH THE ARRIVING SHORTWAVE DISTURBANCE... PUSHES SOUTH OUT OF CANADA...SENDING WHAT WAS THE WARM FRONT TO THE SOUTH. THIS SIGNIFICANTLY INCREASE THE COMPLEXITY OF THE TEMPERATURE PROFILES RESULTING IN MOSTLY RAIN IN THE SOUTHERN ZONES AND MOSTLY SNOW IN THE NORTHERN ZONES. THE MODELS RAMP UP THE QPF...RANGING FROM 0.15 TO 0.25 FROM 12Z TO 18Z SPREAD ACROSS THE ENTIRE CWA. A STRONG SURFACE PRESSURE GRADIENT FROM THE LEE TROUGH...ALONG WITH STRONG WINDS ALOFT MIXING TO THE SURFACE WILL PRODUCE STRONG NW WINDS OF AROUND 30 KTS THAT WILL BE MOSTLY ASSOCIATED WITH AREAS OF RAIN. WINDS WILL BE MUCH WEAKER IN THE EASTERN ZONES. WINDS COULD CAUSE SOME DRIFTING AND BLOWING SNOW IN THE AREAS OF SNOWFALL. TEMPERATURE SHOULD BE THE WARMEST ON WEDNESDAY UNTIL THE COLD FRONT DROPS TEMPERATURES IN THE AFTERNOON. SNOW AMOUNTS WILL BE DIFFICULT TO DETERMINE SINCE THEY WILL DEPEND OF THE TEMPERATURE PROFILES ALOFT AND NEAR THE SURFACE. CURRENT THOUGHTS FOR STORM TOTALS WILL BE IN A RANGE OF AROUND 1 TO 3 INCHES. THE WAY THE MODELS ARE COMING TOGETHER... THIS UNCERTAINTY SHOULD DIMINISH IN THE NEXT FEW MODEL RUNS. BY LATE AFTERNOON THE COLD FRONT WILL HAVE PUSHED ALL THE WAY SOUTH THROUGH NEMONT CHANGING ALL PRECIPITATION OVER TO SNOW. AFTERNOON QPF WILL BE MUCH REDUCED TO AROUND 0.05 TO 0.10 INCH. NORTHWEST WINDS WILL CONTINUE STRONG AT AROUND 20 KTS. WEDNESDAY NIGHT AND THURSDAY...THE COLD FRONT CONTINUES FARTHER SOUTH REACHING COLORADO BY THURSDAY MORNING. NORTHWEST WINDS REINFORCED BY CAA WILL NOT LET UP THROUGH THURSDAY. GENERAL TROUGHINESS AND INSTABILITY WILL SUSTAIN LIGHT SNOW SHOWERS THROUGH THURSDAY AFTERNOON. THICKNESS HEIGHTS FALL ALL THE WAY TO AROUND 520DM BY 00Z FRIDAY BUT WINDS WILL HELP MODERATE HIGH TEMPERATURES WHICH SHOULD BE NEAR NORMAL. SCT .LONG TERM...THURSDAY NIGHT THROUGH TUESDAY... THURSDAY NIGHT AND FRIDAY LOOK RELATIVELY QUIET ALTHOUGH WEAK WAVES ON NORTHWEST FLOW COULD BRING A FEW FLAKES OF SNOW. WILL MENTION A SLIGHT CHANCE IN MOST AREAS FOR NOW. THE GFS AND GEM ARE FASTER THAN THE ECMWF WITH BRINGING A WINTER STORM WITH AN ARCTIC COLD FRONT ACROSS MONTANA FOR THE WEEKEND. GFS HAS SHOWN BETTER RUN TO RUN CONSISTENCY IN FORECASTING THIS STORM WITH THE HEAVY SNOW BAND TRACKING ACROSS MONTANA WITH SLIGHT VARIATIONS. THE ECMWF HAS VARIED THE FORECAST OF THE MAIN SNOW BAND FROM ACROSS THE HI LINE OF MONTANA IN LAST NIGHT'S RUN TO SOUTH OF THE FORECAST AREA IN THE 12Z RUN AND SOUTHERN ALBERTA AND SASKATCHEWAN IN ITS CURRENT RUN. THE GEM CURRENTLY TRACKS THE HEAVIEST SNOW ALONG THE MT/CANADA BORDER. GIVEN THAT THIS STILL HAS A GOOD POSSIBILITY OF BEING A HIGH IMPACT EVENT...WILL MAINTAIN A HIGH CHANCE OF SNOW FOR SATURDAY AND SUNDAY. ARCTIC HIGH PLUNGING SOUTH INTO THE SASKATCHEWAN SATURDAY NIGHT AND SUNDAY MAY END THE SNOW SOONER THAT CURRENTLY FORECASTED. WITH MODELS VARYING ON WHEN THE SNOW WILL EXIT THE REGION...WILL WAIT ANOTHER MODEL RUN OR TWO BEFORE SIGNIFICANTLY LOWERING THE CHANCE OF SNOW SATURDAY NIGHT AND SUNDAY. WILL CONTINUE TO HIGHLIGHT IT IN A HAZARDOUS WEATHER OUTLOOK. MODELS DIFFER ON THE DEPTH OF THE UPPER TROUGH THAT FOLLOWS THIS SYSTEM EARLY NEXT WEEK. EITHER WAY...TEMPERATURES WILL BE COLDER THAN NORMAL WITH NIGHTTIME LOWS BELOW ZERO AT TIMES. A WEAK SHORTWAVE COULD BRING A FEW SNOW SHOWERS ON MONDAY. WILL MENTION A SLIGHT CHANCE FOR NOW. TUESDAY LOOKS DRY AND COLD. FORRESTER && .AVIATION... VFR. MID LEVEL CLOUDS WILL MOVE INTO THE AREA THIS MORNING WITH SOUTH TO SOUTHWEST WINDS UNDER 10 KNOTS. CEILINGS WILL LOWER TO 4000 TO 5000 FEET THIS AFTERNOON WITH ISOLATED RAIN OR SNOW SHOWERS AND WEST WINDS 10 TO 15 KNOTS. EXPECT MAINLY LOW VFR LEVEL CLOUDS TONIGHT. A WIDESPREAD BAND OF RAIN AND SNOW BEGINS TO MOVE INTO THE AREA AROUND 06Z WEDNESDAY. /GAH && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 320 AM MST TUE FEB 21 2012 MTZ016>027-059>062-221000- 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- 320 AM MST TUE FEB 21 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY AFTER MIDNIGHT TONIGHT THROUGH WEDNESDAY NIGHT... A STRONG AND COMPLEX WINTER STORM SYSTEM CONSISTING OF A WARM FRONT QUICKLY FOLLOWED BY A COLD FRONT WILL BRING RAIN TO SOME AREAS AND ACCUMULATING SNOW TO OTHER AREAS OF NORTHEAST MONTANA. SOME AREAS WILL HAVE PERIODS OF RAIN AND PERIODS OF ACCUMULATING SNOW. BY WEDNESDAY EVENING ALL PRECIPITATION WILL BECOME SNOW. ALTHOUGH PRECIPITATION AMOUNTS AND TEMPERATURES REMAIN UNCERTAIN...RAIN AMOUNTS UP TO A QUARTER INCH AND SNOW AMOUNTS UP TO 3 INCHES ARE POSSIBLE BY WEDNESDAY EVENING. STRONG NORTHWEST WINDS OF 20 TO 35 MILES PER HOUR WITH GUSTS TO AS HIGH AS 50 MILES PER HOUR WILL BE POSSIBLE WITH THIS STORM. THE STRONGEST WINDS WILL BE SOUTH OF THE MISSOURI RIVER. THERE IS A POSSIBILITY OF A SIGNIFICANT WINTER STORM SATURDAY AND SUNDAY ACROSS EASTERN MONTANA. THERE IS UNCERTAINTY WITH REGARD TO THE STRENGTH AND TRACK OF THE STORM AT THIS TIME. IT WILL BE MONITORED THROUGHOUT THE WEEK FOR POSSIBLE WINTER WEATHER HIGHLIGHTS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The national radar mosaic for the moment the first event began.
2 high wind. Local standard time, as filed.
Sustained winds of 40 to 50 mph were reported at the Buckhorn Store in Zortman. A mobile RAWS site just over the county line also confirmed high winds across the area with a reported 68 mph gust in northeastern Fergus County.
Cooperative observer at 13NE Grass Range reported wind gusts up to 50 mph downing tree limbs up to 5-inches in diameter, blowing away loose objects, and peeling up corners of 3 tin roofs.
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, February 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: 364917, 364920.