High pressure behind a moist winter storm left low level moisture trapped under an inversion. This resulted in areas of dense fog.
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 GJT wrote it up.
High pressure behind a moist winter storm left low level moisture trapped under an inversion. This resulted in areas of dense fog.
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 Dec 12, 9:58 PM MST, 2 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE GRAND JUNCTION CO 958 PM MST SAT DEC 12 2015 .UPDATE... ISSUED AT 932 PM MST SAT DEC 12 2015 LATE THIS EVENING SATELLITE IMAGERY AND ANALYSIS SHOW THE SURFACE LOW WAS MOVING INTO OKLAHOMA WITH THE UPPER LOW ROTATING OVER CENTRAL NEW MEXICO. A PLUME OF DIVERGENT UPLIFT STRETCHED FROM EASTERN NM TO SOUTHERN CO. AS THE UPPER LOW MOVED GRADUALLY EAST THERE APPEARS TO BE A BIT OF RETURN FLOW...TAKING CLOUDS AND SHOWERS TO THE WEST OVER SOUTHERN AND CENTRAL CO. THIS CAN BE SEEN IN THE RADAR RETURNS AS WELL. A SMALL BAND OF ENHANCE PRECIP WAS ALSO MOVING NORTH THROUGH THE EASTERNMOST COUNTIES OF THE FORECAST AREA...BRINGING SOME STRONGER SHOWERS TO GUNNISON AND ASPEN. BELIEVE THIS IS THE LAST GASP FOR WESTERN CO AND SNOWFALL SHOULD END AFTER MIDNIGHT. && .SHORT TERM...(THIS EVENING THROUGH SUNDAY NIGHT) ISSUED AT 130 PM MST SAT DEC 12 2015 LOW PRESSURE HAD CLOSED OFF OVER NORTHWESTERN NM THIS AFTERNOON...PUMPING MOISTURE FROM SOUTH TO NORTH ACROSS CENTRAL COLORADO. WRAP-AROUND ENHANCEMENT WAS DEVELOPING ALONG THE PARACHUTE TO NUCLA AREA. WITH MOST OF THIS SYSTEM'S DYNAMICS SHIFTED EAST OF THE FORECAST AREA...ADDITIONAL SNOWFALL WILL TURN INTO AN OROGRAPHIC EVENT THIS EVENING. DECIDED TO EXTEND NORTHERN SAN JUANS ADVISORY UNTIL MIDNIGHT TONIGHT...WITH A SLIGHT GORGE SIGNATURE ON THE SOUNDINGS. THAT BEING SAID...NOT EXPECTING A GIANT GORGE EVENT...BUT RATHER SOME ENHANCEMENT FROM JUST SOUTH OF OURAY UP TO THE MONUMENT ON HIGHWAY 550 FOR A FEW HOURS THIS EVENING. ALL OTHER WARNINGS AND ADVISORIES WILL END AT 6PM UNLESS OTHERWISE CANCELLED EARLIER. THE SNOW IS EXPECTED TO END FROM NORTH TO SOUTH AS THE CLOSED LOW PROGRESSES EASTWARD THROUGH THE NIGHT. AREAS OF FOG ARE EXPECTED TONIGHT IN THE USUAL LOCATIONS...THE UINTA BASIN...ALONG THE I-70 CORRIDOR BETWEEN GREEN RIVER AND PALISADE...GRAND JUNCTION TO RIDGWAY CORRIDOR...AND THE SOUTHWEST CO VALLEYS. SUNDAY A TRANSIENT RIDGE BUILDS IN FROM THE WEST BACKING THE UPPER WINDS FROM NORTH TO WEST AND BRINGING STRONG WARM ADVECTION TO THE SLOPES. THE VALLEY INVERSIONS WILL REFORM. SUNDAY NIGHT THE NEXT COLDER NORTHERN PACIFIC TROUGH WORKS INTO THE GREAT BASIN. SW GRADIENT WINDS INCREASE ALOFT AND SHOWERS BEGIN OVER THE NE UTAH MTNS TOWARDS MORNING. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 130 PM MST SAT DEC 12 2015 THE SLOWER EC SOLUTION WAS GENERALLY FAVORED FOR THESE PERIODS. MONDAY...THE TROUGH CLOSES OVER NE UTAH WITH 95KT JET SUPPORT INTO THE FOUR CORNERS. THE COLD FRONT WORKS THROUGH THE CWA THROUGH THE AFTERNOON AND EVENING BRINGING DYNAMICAL LIFT. SNOW LEVELS WILL BE INTO THE VALLEY BOTTOMS. SNOW ACCUMULATIONS LOOK WIDESPREAD WITH ONLY SE UTAH LEFT OUT OF THE BETTER ACCUMULATIONS. BY MONDAY EVENING THE STORM EVOLVES INTO A NW-SLOPES OROGRAPHIC EVENT. THE NE UTAH MTNS LOOK TO BE FAVORED INITIALLY WITH PRODUCTIVE NW FLOW MONDAY AFTERNOON THROUGH TUESDAY. 700MB TEMPERATURES DROP TO A COLD AND SNOW-EFFICIENT -12C. WITH SNOW TOTALS RUN FROM QPF AND USING HIGH SNOW RATIOS...THE MTNS LOOK TO GENERALLY GET 6-12 INCHES MONDAY THROUGH TUESDAY. MOST VALLEYS WILL GET SOME SNOW ACCUMULATIONS TOO. THE SOUTHERN AND CENTRAL VALLEYS COULD GET SIGNIFICANT SNOW ON MONDAY WHILE THE NORTHERN VALLEYS MAY SEE THEIR BEST ACCUMULATIONS MONDAY NIGHT INTO TUESDAY. WEDNESDAY-WEDNESDAY NIGHT...AN OPEN COLD WAVE PASSES IN NW FLOW KEEPING SNOW PRODUCTION ALONG NW FACING SLOPES FOR ALL MTNS EXCEPT SE UTAH. IMPRESSIVELY COLD AIR REMAINS OVER THE REGION ON WEDNESDAY THAT MODIFIES ON THURSDAY. NW WINDS INCREASE OVER THE HIGHER TERRAIN ON THURSDAY FOR CONTINUED SENSIBLE COLD CONDITIONS, FRIDAY-SATURDAY...THE NEXT RIDGE BUILDS OVER THE FORECAST AREA BRINGING MILDER CONDITIONS TO THE SLOPES OVER VALLEY INVERSIONS WHERE TEMPERATURES WILL REMAIN COLD WITH NEW SNOW ACCUMULATIONS AND POTENTIAL FOG ALLOWING LITTLE WARMING. SW FLOW DEVELOPS NEXT WEEKEND AS THE NEXT PACIFIC TROUGH MAKES LANDFALL. && .AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT) ISSUED AT 932 PM MST SAT DEC 12 2015 SNOWFALL WILL CONTINUE AT THE HIGHER AIRPORTS UNTIL ABOUT MIDNIGHT THEN CLEAR FAIRLY RAPIDLY FROM THE WEST. KASE IS THE LAST TAF SITE EXPERIENCE HEAVIER SNOWFALL BUT SHOULD SEE THE IFR CIGS AND VSBYS IMPROVE BETWEEN 06Z AND 08Z. MOUNTAINS WILL REMAIN OBSCURED GENERALLY EAST OF A LINE FROM KCEZ TO KGJT TO KCAG...WITH IMPROVEMENT AFTER ABOUT 09Z TONIGHT. FOG AT KDRO SHOULD KEEP IFR VSBYS AND OCCASIONAL IFR CIGS THERE UNTIL ABOUT 14Z. THERE IS A RISK FOR DEGRADED CONDITIONS IN FOG AT KEGE...KRIL...AND KMTJ UNTIL ABOUT 15Z. EXPECT VFR CONDITIONS ACROSS THE AREA SUNDAY AND SUNDAY EVENING. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ018. UT...NONE. && UPDATE...CC SHORT TERM...JM/JOE LONG TERM...JOE AVIATION...CC
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 539 AM MST SAT DEC 12 2015 COZ001>014-017>023-UTZ022>025-027>029-131245- 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-FLAT TOPS- 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- 539 AM MST SAT DEC 12 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT MANY WINTER STORM WARNINGS AND ADVISORIES REMAIN IN PLACE WITH 2 TO 4 INCHES EXPECTED IN MANY VALLEYS AND ANYWHERE FROM 6 TO 12 INCHES EXPECTED IN THE MOUNTAINS. CONDITIONS WILL IMPROVE AS THE DAY PROGRESSES FROM WEST TO EAST WITH THE MOUNTAINS SEEING MOST OF THE PRECIPITATION TODAY. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY ANOTHER STORM SYSTEM WILL MOVE INTO THE AREA MONDAY AND TUESDAY BRINGING ANOTHER CHANCE FOR WIDESPREAD PRECIPITATION. ACCUMULATING SNOWFALL IS EXPECTED FOR MANY AREAS FROM THIS NEXT SYSTEM. ONCE THE STORM PASSES...MUCH COLDER TEMPERATURES WILL FILTER DOWN FROM THE NORTH. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY OR TONIGHT...HOWEVER SPOTTERS ARE ENCOURAGED TO REPORT SNOWFALL AMOUNTS TO THE NATIONAL WEATHER SERVICE IN GRAND JUNCTION.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
418 PM MST SAT DEC 12 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0700 AM SNOW SILVERTON 37.81N 107.66W
12/12/2015 M7.0 INCH SAN JUAN CO TRAINED SPOTTER
&&
EVENT NUMBER GJT1501483
MMSPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
500 PM MST SAT DEC 12 2015
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0330 PM SNOW 3 N KEBLER PASS 38.89N 107.10W
12/12/2015 M3.0 INCH GUNNISON CO SKI AREA
&&
EVENT NUMBER GJT1501484
MMSThe national radar mosaic for the moment the first event began.
2 dense fog. Local standard time, as filed.
Dense fog occurred in some lower elevation areas of La Plata County. Visibilities occasionally dropped down to a quarter mile at the Durango-La Plata County Airport within a seven hour period.
Dense fog occurred in the lower elevation areas surrounding and including the town of Craig. Visibilities occasionally dropped down to a quarter mile at the Craig-Moffat County Airport within a seven hour period.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Colorado in 2015Every state in 2015This day in weather historyWarnings in Colorado, 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: 608485, 608487.