As western Colorado transitioned from fall to winter the storm track became more favorable for precipitation across the eastern Great Basin and northern Rockies, especially during the latter half of the month. Half of the climate reporting systems over western Colorado collected above normal precipitation for the first time in many months.
Every event with a place to put it; 21 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 GJT wrote it up.
As western Colorado transitioned from fall to winter the storm track became more favorable for precipitation across the eastern Great Basin and northern Rockies, especially during the latter half of the month. Half of the climate reporting systems over western Colorado collected above normal precipitation for the first time in many months. The central and southern mountain ranges and adjacent valleys however continued to receive below normal precipitation through November. Overall the precipitation was not enough to ease drought conditions and little change was seen in the severe to extreme categories in place across western Colorado.
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 Grand Junction, CO wrote its last area forecast discussion before the first event at Nov 30, 9:59 PM MST, 2 hours 1 minute earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 959 PM MST FRI NOV 30 2012 .UPDATE... ISSUED AT 722 PM MST FRI NOV 30 2012 MOIST SHORT WAVE IS MARCHING ACROSS THE GREAT BASIN WITH THE LEADING EDGE OF THE DEEPER CLOUD MASS JUST REACHING WRN COLORADO. THIS SHORT WAVE CONTAINS GOOD MOISTURE BUT MOVES VERY QUICKLY. HIGHER RESOLUTION MODELS SUCH AS THE HRRR INDICATING SOME PCPN AS FAR SOUTH AS THE LA SAL AND THE NRN SIDE OF THE SAN JUAN MOUNTAINS. BUT THE NRN MOUNTAINS STAND THE BEST CHANCE OF SNOW WITH 3-5 INCH ACCUMULATION POSSIBLE ABOVE 9000 FEET. WARM AIR MASS RESULTS IN HIGH SNOW LEVELS AND APPEARS WILL RANGE FROM 7500 TO 8000 FEET OVERNIGHT. BOOSTED VALUES IN THE POP GRIDS...PRIMARILY OVER NW COLORADO. BY DAYBREAK...THIS SHORT WAVE WILL HAVE CROSSED THE DIVIDE WITH A CLEARING TREND FROM THE WEST. && .SHORT TERM...(THIS EVENING THROUGH SATURDAY NIGHT) ISSUED AT 317 PM MST FRI NOV 30 2012 MID AND HIGH LEVEL CLOUDS CONTINUE TO STREAM INTO THE FORECAST AREA AS AN UPPER LEVEL LOW PRESSURE SYSTEM OFF THE PACIFIC NORTHWEST COAST CONTINUES TO SPIN...BRINGING IN A STEADY STREAM OF MOISTURE. 700MB WINDS ARE IN THE 35 TO 45 KT RANGE WITH AN UPPER LEVEL JET OF 80 KTS OVERHEAD IN A SOUTHWEST TO WEST FLOW. VISIBLE SATELLITE AND VISUAL OBSERVATIONS INDICATE MOUNTAIN WAVE CLOUDS ALREADY FORMING OVER THE UNCOMPAHGRE PLATEAU AND ON THE LEE SIDE OF SOME RIDGES...WHICH WOULD INDICATE A STABLE ATMOSPHERE. SOME GUSTS ARE REACHING THE SURFACE AT CRAIG AND MEEKER WHICH HAVE BEEN GUSTING ANYWHERE FROM 20 TO 30 KTS. THIS IS ALL OUT AHEAD OF AN EMBEDDED DISTURBANCE THAT WILL MOVE THROUGH THIS EVENING THROUGH SATURDAY MORNING. THE BEST DYNAMICS LIE NORTH OF THE FORECAST AREA AS THIS DISTURBANCE TRACKS FROM NORTHERN NEVADA THROUGH NORTHERN UTAH INTO SOUTHERN IDAHO AND WYOMING. AREAS NORTH OF I-70 WILL PRIMARILY BE AFFECTED BY THIS DISTURBANCE AS IT CLIPS THESE ZONES. WHEN ANALYZING TIME HEIGHTS OVER SEVERAL POINTS ACROSS THESE AFFECTED AREAS...700MB TEMPERATURES WERE ANYWHERE FROM -1C TO -3C WHICH WOULD PUT SNOW LEVELS AT ABOUT 7000 TO 8000 FT. WHILE THERE IS MOISTURE AND INSTABILITY...THE FORCING IS NOT ALL THAT STRONG AND THE SATURATED MOISTURE LAYER IS FAIRLY SHALLOW. MUCH OF THE FORCING IS CAPPED BY A FAIRLY STABLE LAYER OVERHEAD. WITH THAT BEING SAID...IT LOOKS LIKE THE EASTERN UINTAS...PARK AND GORE MOUNTAINS AS WELL AS THE ELKHEADS AND FLATTOPS WILL BE FAVORED FOR ACCUMULATING SNOWFALL IN THE 1 TO 2 INCH RANGE WITH SOME SPOTS SEEING AS MUCH AS 3. PRIMARILY LIGHT RAIN WILL OCCUR IN THE NORTHERN VALLEYS. THE BULK OF THE PRECIPITATION LOOKS TO OCCUR AFTER MIDNIGHT TO AROUND SUNRISE. THE REST OF THE FORECAST AREA WILL SEE LITTLE IF ANY PRECIPITATION...JUST SOME INCREASED CLOUD COVER. LEANED TOWARDS THE WARMER SIDE OF GUIDANCE TONIGHT FOR LOW TEMPERATURES DUE TO INCREASED CLOUD COVER. SHOWERS WILL TAPER OFF AFTER SUNRISE AND WILL BE LIMITED TO THE HIGHER PEAKS OF THE NORTHWEST COLORADO MOUNTAINS THROUGH ABOUT NOON AS MOISTURE AND CLOUDS WILL HUG THE TERRAIN. ALTHOUGH PRECIP WILL COME TO AN END AND CLOUD HEIGHTS WILL RISE SATURDAY AFTERNOON...SOME HIGH CLOUDS WILL CONTINUE TO MOVE THROUGH AS THE UPPER LEVEL LOW FEEDS MORE MOISTURE INTO THE AREA. EVEN THOUGH THERE WILL BE A SLIGHT COOL DOWN ON SATURDAY FROM FRIDAYS HIGHS PARTICULARLY UP NORTH...AFTERNOON HIGH TEMPERATURES WILL STILL REMAIN SOME 10 TO 15 DEGREES ABOVE NORMAL FOR EARLY DECEMBER. .LONG TERM...(SUNDAY THROUGH FRIDAY) ISSUED AT 317 PM MST FRI NOV 30 2012 HIGH CLOUDS OUT AHEAD OF THE NEXT PACIFIC WAVE WILL BEGIN TO SPREAD OVER THE FORECAST AREA EARLY SUNDAY...THEN THICKEN AND LOWER DURING THE AFTERNOON. MODELS CONTINUE TO SHOW A WEAKENED SYSTEM AS COMPARED TO WHAT WAS PROGGED SEVERAL DAYS AGO. SO IN LIGHT OF THAT EARLIER PROMISE AND BECAUSE WE REALLY NEED THE MOISTURE...THIS STORM IS LOOKING LIKE IT WILL BE A DISAPPOINTMENT. THAT SAID...WINDS WILL STRENGTHEN SUNDAY AFTERNOON...AND PRECIPITATION WILL INCREASE THROUGH THE EVENING HOURS...BOTH FAVORING THE NORTH. I HAVE SPLIT THE EVENING GRID INTO 3 HOUR BLOCKS TO ADDRESS THIS PRECIPITATION TREND. THERE ALSO CONTINUES TO BE SOME MODEL TIMING DIFFERENCES. THE ASSOCIATED COLD FRONT WILL REACH THE NORTHWEST CORNER LATE IN THE EVENING INTO THE OVERNIGHT PERIOD...DEPENDING ON THE MODEL. THE FRONT WILL QUICKLY WEAKEN AS IT HEADS SOUTH...MOSTLY WASHING OUT BY THE TIME IT REACHES SAN JUAN MOUNTAINS MON MORNING. THE GFS IS THE FASTER MODEL WITH THE NAM AND ECMWF LAGGING BY JUST A FEW HOURS. THE LOW AMPLITUDE UPPER TROUGH AXIS FOLLOWS NOT FAR BEHIND FRONT...SO THE BEST PRECIPITATION WILL BE FROM LATE IN THE EVENING THROUGH THE OVERNIGHT HOURS. THE GFS SHOWS SHOWERS QUICKLY DIMINISHING BY MID MORNING ON MON. THE EC AND NAM KEEP THINGS GOING THROUGH THE MORNING AT LEAST...WITH MOUNTAIN SHOWERS LINGERING THROUGH THE AFTERNOON. THINK THE GFS IS TOO FAST IN AGREEMENT WITH HPC...SO HAVE EXTENDED BETTER POPS INTO MON. THIS STORM DOES NOT PACK MUCH COLD AIR SO SNOW LEVELS WILL REMAIN RELATIVELY HIGH. EXPECT RAIN TO CHANGE OVER TO SNOW ACROSS MOST OF THE NORTHERN AND HIGHER VALLEYS. BUT PRECIPITATION IN THE OTHER VALLEYS COULD REMAIN LIQUID...OR MIXED PHASE AT BEST. HIGHS ON MON WILL STILL BE IN THE 50S ACROSS THE SOUTHERN AND CENTRAL VALLEYS AT THE MID-LOWER ELEVATIONS. ONCE THE STORM HAS EXITED TO THE EAST...STORM TOTAL SNOW AMOUNTS OVER THE MOUNTAINS SHOULD REACH A FEW INCHES...WITH THE NORTH SEEING THE BEST ACCUMULATIONS. ADVISORY AMOUNTS MAY BE POSSIBLE FOR THE NORTH AND CENTRAL MOUNTAINS. BUT THE SHORT DURATION AND WARM NATURE OF THE STORM...ARE LIMITING FACTORS. DRIER AND WARMER CONDITIONS FOLLOW TROUGH MIDWEEK. THEN ANOTHER PACIFIC TROUGH AND COLD FRONT IS PROGGED TO PASS OVER THE REGION WED NIGHT-THU NIGHT. THE MODELS HAVE AGAIN TRENDED WEAKER WITH THIS SYSTEM COMPARED TO WHEN IT WAS FIRST ADVERTISED A COUPLE OF DAYS AGO. ALSO THERE CONTINUES TO BE SOME TIMING DIFFERENCES WITH THE GFS STILL THE FASTER MODEL. SO FAR THIS SYSTEM PACKS A COLDER CORE THAN THE ONE ON SUN NIGHT/MON. AND IF MODELS DO NOT WEAKEN IT TOO MUCH...THIS STORM SHOULD AGAIN BRING A ROUND OF MOUNTAIN SNOW...WITH A CHANCE OF VALLEY RAIN AND/OR SNOW SHOWERS. MODEL INCONSISTENCIES GROW BEYOND THIS WAVE...BUT COOLER TEMPERATURES SHOULD FOLLOW WITH DRIER CONDITIONS ON FRIDAY. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT) ISSUED AT 959 PM MST FRI NOV 30 2012 LOWER CIGS THROUGH 15Z BUT MAINTAINING VFR FOR MOST AREAS. MOUNTAIN AIRPORTS MAY HAVE CIGS LOWERING TO BELOW AIRPORT MINIMUMS FOR BRIEF PERIDS FROM PASSING -SHRA/-SHSN SNOW LEVEL NEAR 075-080. MOUNTAIN TOPS WILL BE PARTIALLY OBSCURED IN SNOW AND FOG. EXPECT MECHANICAL TURBULENCE ACROSS THE REGION. AFTER 15Z...IMPROVING CONDITIONS WITH LOCAL -SHSN ENDING AND DISSIPATING CIGS. VFR EXPECTED AT ALL TAF SITES. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...NONE. UT...NONE. && UPDATE...PF SHORT TERM...MDA LONG TERM...EH AVIATION...PF
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 424 AM MST FRI NOV 30 2012 COZ001>014-017>023-UTZ022>025-027>029-011130- LOWER YAMPA RIVER BASIN-CENTRAL YAMPA RIVER BASIN- ROAN AND TAVAPUTS PLATEAUS-ELKHEAD AND PARK MOUNTAINS- UPPER YAMPA RIVER BASIN-GRAND VALLEY-DEBEQUE TO SILT CORRIDOR- CENTRAL COLORADO RIVER BASIN-GRAND AND BATTLEMENT MESAS- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAIN VALLEYS- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- WEST ELK AND SAWATCH MOUNTAINS-FLATTOPS- UPPER GUNNISON RIVER VALLEY-UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE- NORTHWEST SAN JUAN MOUNTAINS-SOUTHWEST SAN JUAN MOUNTAINS- PARADOX VALLEY/LOWER DOLORES RIVER- FOUR CORNERS/UPPER DOLORES RIVER-ANIMAS RIVER BASIN- SAN JUAN RIVER BASIN-SOUTHEAST UTAH-EASTERN UINTA MOUNTAINS- EASTERN UINTA BASIN-TAVAPUTS PLATEAU-ARCHES/GRAND FLAT- LA SAL AND ABAJO MOUNTAINS-CANYONLANDS/NATURAL BRIDGES- 424 AM MST FRI NOV 30 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT SNOW IS LIKELY ACROSS THE EASTERN UINTA MOUNTAINS AND THE MOUNTAINS AROUND STEAMBOAT SPRINGS TONIGHT. SNOW AMOUNTS WILL BE ONLY AN INCH OR TWO...BUT WIND GUSTS UP TO 40 MPH OVER THE HIGHER TERRAIN OF THESE MOUNTAINS WILL PRODUCE PERIODS OF BLOWING SNOW AND LOWER VISIBILITY FOR TRAVELERS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY SNOWFALL OVER THE NORTHERN AND CENTRAL COLORADO AND UTAH MOUNTAINS WILL DECREASE SATURDAY...PRODUCING LOCALLY HAZARDOUS DRIVING CONDITIONS FROM DECREASED VISIBILITY. THE NEXT PACIFIC STORM SYSTEM WILL AFFECT THE AREA SUNDAY NIGHT AND MONDAY...WITH HAZARDOUS WINTER CONDITIONS POSSIBLE IN THE MOUNTAINS AND HIGH PASSES. ANOTHER PACIFIC SYSTEM MAY BRING MORE WINTER WEATHER TO THE AREA THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT...HOWEVER SPOTTERS ARE ENCOURAGED TO REPORT ANY SNOWFALL AMOUNTS TO THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION. JAD/CJC
The national radar mosaic for the moment the first event began.
21 drought. Local standard time, as filed.
Extreme drought conditions remained unchanged across the lower Yampa River basin and the northwest Colorado plateau region through December.
Extreme drought conditions remained unchanged across the central Yampa River basin and the northwest Colorado plateau region through December.
Extreme drought conditions remained unchanged across the high plateaus of west central Colorado through December.
Extreme drought conditions remained unchanged across the Park and Elkhead Mountains of northwest Colorado, while severe drought condition remained in place across the Gore Mountain Range.
Extreme drought conditions remained unchanged across the upper Yampa River basin through the month of December.
Extreme drought conditions remained unchanged across the Grand valley in west central Colorado through the month of December.
Severe to extreme drought conditions remained unchanged along the central Colorado River basin in west central Colorado through the month of December.
Severe drought conditions remained unchanged along the central Colorado River basin in west central Colorado through the month of December.
Severe drought conditions remained unchanged over the high mesa region of west central Colorado through the month of December.
Severe drought conditions remained unchanged over the central Colorado mountains through the month of December.
Severe drought conditions remained unchanged along the lower Gunnison and Uncompahgre river basins through the month of December.
Severe to extreme drought conditions remained unchanged over the West Elk and western Sawatch mountain ranges through the month of December.
Severe to extreme drought conditions remained unchanged over the upper Gunnison River valley through the month of December.
Severe to extreme drought conditions remained unchanged over the Uncompahgre Plateau region through the month of December.
Severe drought conditions remained unchanged over the San Juan Mountains through the month of December.
Severe drought conditions remained unchanged over the San Juan Mountains through the month of December.
Severe drought conditions remained unchanged throughout the Animas River basin during the month of December.
Severe drought conditions remained unchanged over the San Juan River basin during the month of December.
Severe drought conditions remained unchanged over the extreme southwest corner of Colorado during the month of December.
Severe to extreme drought conditions remained unchanged over the Flat Top Mountains through the month of December.
Extreme to severe drought conditions remained unchanged over the Paradox Valley and lower Dolores River basin in southwest Colorado through the month of December.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2012Every state in 2012This day in weather historyWarnings in Colorado, December 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: 423719, 423720, 423721, 423722, 423723, 423724, 423725, 423726, 423727, 423728, 423729, 423730, 423731, 423732, 423733, 423734, 423735, 423736, 423737, 423793, 423825.