A strong low pressure system passed over the central and northern Rockies, directing moisture and cold air to favor accumulating snow across portions of northeast Montana.
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 strong low pressure system passed over the central and northern Rockies, directing moisture and cold air to favor accumulating snow 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 Dec 13, 9:21 PM MST, 3 hours 39 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED NATIONAL WEATHER SERVICE GLASGOW MT 921 PM MST SUN DEC 13 2015 .SHORT TERM...FOR NORTHEAST MONTANA...TONIGHT THROUGH TUESDAY... ...WINTER STORM SET TO IMPACT NORTHEAST MONTANA TONIGHT INTO TUESDAY... RADAR ECHOES ARE DRIFTING INTO SOUTHWEST AREAS OF NORTHEAST MONTANA THIS EVENING AT AROUND 20 DBZ. NO NEARBY STATIONS HAVE REPORTED PRECIPITATION YET. STRONGER ECHOES CAN BE SEEN UPSTREAM. SO THE STORM DEVELOPMENT IS ON TRACK TO BEGIN WITH MINIMAL IMPACTS...WHERE SURFACE TEMPERATURES ARE STILL ABOVE FREEZING. THE STORM SHOULD BEGIN TO WIND UP AFTER MIDNIGHT WHEN FALLING TEMPERATURES COINCIDE WITH STRONGER ECHOES. MAIN CHANGES WERE TO ADJUST MINIMUM TEMPERATURE SINCE A FEW LOCATIONS WERE ALREADY BELOW THE MINIMUMS. FEW OTHERE CHANGES WERE NEEDED TO THE ON- GOING FORECAST. SCT PREVIOUS DISCUSSION... A WET PACIFIC STORM SYSTEM CURRENTLY OVER THE PACIFIC NORTHWEST WILL ADVANCE EASTWARD TONIGHT. AS IT DOES SO IT WILL ADVANCE WARM AND MOIST AIR ALOFT OVER A COLDER AIRMASS AT THE SURFACE... SETTING THE STAGE FOR A FREEZING RAIN EVENT. OVERALL ACCUMULATIONS OF FREEZING RAIN TONIGHT INTO MONDAY MORNING LOOK TO BE ON THE LIGHT SIDE...BUT ANY AMOUNT OF FREEZING RAIN WILL CAUSE TRAVEL ISSUES AS ROADWAYS AND SIDEWALKS BECOME SLIPPERY. THE BEST POTENTIAL FOR ACCUMULATIONS LIES ACROSS SOUTHERN PHILLIPS... PETROLEUM...GARFIELD...AND EXTREME SOUTHWEST VALLEY COUNTIES. A SURFACE COLD FRONT WILL PUSH THROUGH FROM NORTHWEST TO SOUTHEAST MONDAY MORNING...CHANGING THE PRECIP TYPE OVER TO ALL SNOW AS IT PASSES. MOISTURE WILL ALSO CONTINUE TO INCREASE MONDAY MORNING AND AFTERNOON...AND MODERATE TO HEAVY SNOWFALL WILL RESULT...WITH THE AFOREMENTIONED AREAS IN THE CROSSHAIRS. THUS UPGRADED THE CURRENT WATCH TO A WINTER STORM WARNING FOR THE COMBINATION OF FREEZING RAIN AND ACCUMULATING SNOW. MONDAY NIGHT WIDESPREAD SNOW WILL CONTINUE TO SLOWLY WORK ITS WAY EASTWARD ACROSS NORTHEAST MONTANA AS THE SYSTEM DRIFTS THROUGH. WE MAY NEED ADDITIONAL ADVISORIES DURING THIS TIME...BUT DETAILS AT THIS TIME ARE MUDDY ENOUGH THAT WE DECIDED TO HOLD OFF ON ISSUANCE FOR NOW. TUESDAY THE SNOWFALL WILL TAPER OFF FROM NORTHWEST TO SOUTHEAST... WITH THE BIG SHEEP MOUNTAINS SOUTHEAST TOWARD WIBAUX COUNTY RECEIVING THE MOST SIGNIFICANT SNOW. GILCHRIST .LONG TERM...TUESDAY NIGHT THROUGH SUNDAY... AFTERNOON UPDATE... CHANGES TO THE FORECAST OCCURRED MAINLY TOWARDS THE FRONT FOR THE LONG RANGE AROUND TUESDAY NIGHT INTO FRIDAY. TEMPERATURES WERE REDUCED ALONG WITH MODEL GUIDANCE AND IN ACCOUNT OF THE NEW SNOW FALL FROM THE PREVIOUS STORM SYSTEM. TUESDAY NIGHT INTO WEDNESDAY NIGHT ALSO SAY POPS DURING THESE PERIODS RISE AS A SECONDARY SHORTWAVE NOT LONG AFTER THE BIG STORMS THROUGH TUESDAY IS ANTICIPATED. THIS SECONDARY SYSTEM WILL BE A FAST MOVER WITH LIMITED MOISTURE... BUT IS EXPECTED TO PULL ARCTIC AIR IN AND DROP THE TEMPERATURES JUST ENOUGH MORE THAT LIMITED NEW SNOW BANDS WILL POP OUT OF IT. TIMING IS SLIGHTLY OUT OF PHASE AND LIKELY TO CHANGE BY 6-12 HOURS BUT MAIN FOCUS NOW IS WEDNESDAY AFTERNOON AND EVENING. PREVIOUS LONG TERM DISCUSSION... WINTER STORM SYSTEM FOR EARLY IN THE WEEK WILL BE EXITING THE REGION WITH A LITTLE LINGERING SNOW IN THE SOUTHEAST CORNER OF THE STATE TUESDAY NIGHT. AN ARCTIC SHORTWAVE DROPS THROUGH THE CANADIAN PRAIRIES TO FILL IN BEHIND THE EXITING CENTRAL U.S. TROF. THIS WAVE BRINGS A REINFORCING SHOT OF COLDER AIR INTO NORTHEAST MONTANA ALONG WITH A FEW SNOW SHOWERS FOR WEDNESDAY. COLD AIR LINGERS OVER NORTHEAST MONTANA...ENHANCED BY THE FRESH SNOW COVER...EVEN AS AN UPPER RIDGE BEGINS BUILDING INTO THE NORTHERN ROCKIES. THE NEXT UPPER TROF PUSHES ACROSS THE WEST COAST BY THE WEEKEND WITH SOUTHWEST FLOW ACROSS THE DIVIDE TO SPREAD WARMER AIR INTO THE CENTRAL PART OF THE STATE. SO COULD SEE SOME ABOVE FREEZING TEMPERATURES OVER THE HIGHER TERRAIN AREAS NEXT SATURDAY. EBERT && .AVIATION... FLIGHT CATEGORY: VFR DETERIORATING AFTER 09Z. SYNOPSIS: VFR CONDITIONS ARE EXPECTED THIS EVENING AS A WEAK RIDGE PASSES OVER. AFTERWARDS CONDITIONS GET PROGRESSIVELY WORSE AS A WINTER STORM MOVES IN LATE TONIGHT AND LAST THROUGH TUESDAY. FREEZING RAIN: PRECIPITATION WILL BEGIN IMPACTING THE TERMINALS FROM WEST TO EAST STARTING AROUND 09Z AT KGGW AND SPREAD TO THE REMAINING TERMINALS BY 12Z. A BAND OF FREEZING RAIN WILL PRECEDE THE MAIN SYSTEM AND WILL CREATE ICE FOR RUNWAYS MAKING THEM SLICK AND HAZARDOUS FOR LANDING/TAKE-OFF. TRANSITION TO ALL SNOW SHOULD OCCUR BY 18Z IF NOT WELL BEFORE. VSBY AND CEILING OBSTRUCTIONS WILL BE WELL ABOVE IFR AT THIS POINT IN TIME... BUT THAT WILL BE DECEPTIVE WITH ICING. SNOW AND VSBY: TRANSITION TO ALL SNOW SHOULD OCCUR BY 18Z IF NOT WELL BEFORE. AS THE TRANSITION OCCURS VSBYS WILL TYPICALLY DROP DOWN TO 1 TO 2 SM IN IFR WITH SNOW. THE BULK OF THE SYSTEM WILL BE AROUND FOR AWHILE AND NOT EXIT ALL THE TERMINALS UNTIL LATE TUESDAY WINDS: LIGHT AND VARIABLE THIS EVENING EXCEPT FOR EAST AROUND 10 KNOTS AT KGGW AT 5 TO 15 KTS TODAY...WIND BECOMING NORTHEAST LESS THAN 10 KTS OVERNIGHT... AND NORTH 10 TO 15 KTS MONDAY AFTERNOON. GAH/GFF && .GLASGOW WATCHES/WARNINGS/ADVISORIES... WINTER STORM WARNING UNTIL NOON MST TUESDAY FOR CENTRAL AND SOUTHEAST PHILLIPS...CENTRAL AND SOUTHERN VALLEY...GARFIELD... MCCONE...PETROLEUM...PRAIRIE...SOUTHWEST PHILLIPS. && WEATHER.GOV/GLASGOW
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GLASGOW MT 236 PM MST SUN DEC 13 2015 MTZ016-017-021>023-026-060-141200- CENTRAL AND SOUTHEAST PHILLIPS-CENTRAL AND SOUTHERN VALLEY- PETROLEUM-GARFIELD-MCCONE-PRAIRIE-SOUTHWEST PHILLIPS- 236 PM MST SUN DEC 13 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT A WINTER STORM WARNING IS IN EFFECT TONIGHT FOR FREEZING RAIN. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A WINTER STORM WARNING CONTINUES THROUGH TUESDAY MORNING FOR POSSIBLE ACCUMULATING SNOW OF 4 TO 8 INCHES. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. MTZ018>020-024-025-027-059-061-062-141200- DANIELS-SHERIDAN-WESTERN ROOSEVELT-RICHLAND-DAWSON-WIBAUX- NORTHERN PHILLIPS-NORTHERN VALLEY-EASTERN ROOSEVELT- 236 PM MST SUN DEC 13 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHEAST MONTANA. .DAY ONE...THIS AFTERNOON AND TONIGHT PATCHY LIGHT FREEZING RAIN WILL BE POSSIBLE TONIGHT. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY THE THREAT FOR FREEZING RAIN WILL CONTINUE INTO MONDAY MORNING...BEFORE CHANGING OVER TO ALL SNOW. SNOW ACCUMULATIONS ARE EXPECTED THROUGH TUESDAY. .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 winter storm. Local standard time, as filed.
A heavier band of snow lingered longer over southern Petroleum county and resulted in a public report of 12 inches of snow in the town of Winnett. Event times are estimated.
Storm total snowfall reports of 7 inches were received both from a cooperative observer located at the Burke Ranch in the far southwestern corner of Valley County and from a NWS employee at Glasgow. Event times are estimated.
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, December 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: 611591, 611590.