Dense Fog, Grand Valley
- When
- December 31, 9:33 AM MST to 11:59 PM MST
- Where
- Grand Valley forecast zone
- Reported by
- AWOS,ASOS,MESONET,ETC
- Coordinates
- 39.308, -108.185 (the zone’s center; the record gives no point)
Dense Fog in Colorado, December 31, 2003
A strong inversion over the Grand Valley created very moist and stable conditions resulting in a prolonged period of dense fog. The Grand Junction ASOS measured visibility at or below 1/4 mile for several hours.
Where it happened
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
- Tornadoes
- Tropical storms and surge
- Floods
- Wind
- Hail
- Winter weather
- Heat and drought
- Cold
- Fire, smoke and dust
- Marine and coastal
- Other
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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.
What happened
The episode as NWS GJT wrote it up.
A strong inversion over the Grand Valley created very moist and stable conditions resulting in a prolonged period of dense fog. The Grand Junction ASOS measured visibility at or below 1/4 mile for several hours. Off-duty National Weather Service employees reported visibility less than 1/4 mile along interstate 70 from Fruita to Grand Junction and visibility less than 1/16 mile in the Redlands. Mesa County sheriff deputies also indicated widespread dense fog in the Grand Valley. Poor visibility also interrupted routine flights at Walker Field Airport. Dense fog continued into the new year. For a continuation on this event see the January, 2004 Storm Data publication.
What forecasters said that day
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 31, 3:25 AM MST, 6 hours 8 minutes earlier.
Area forecast discussion, Dec 31, 3:25 AM MST, 6 hours 8 minutes before
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</html>Hazardous weather outlook, Dec 31, 4:32 AM MST, 5 hours 1 minute before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE GRAND JUNCTION CO 432 AM MST WED DEC 31 2003 COZ001>014-017>023-UTZ022>025-027>029-011230- ANIMAS RIVER BASIN-ARCHES/GRAND FLAT-CANYONLANDS/NATURAL BRIDGES- CENTRAL COLORADO RIVER BASIN- CENTRAL GUNNISON AND UNCOMPAHGRE RIVER BASIN- CENTRAL YAMPA RIVER BASIN-DEBEQUE TO SILT CORRIDOR- EASTERN UINTA BASIN-EASTERN UINTA MOUNTAINS- ELKHEAD AND PARK MOUNTAINS-FLAT TOPS- FOUR CORNERS/UPPER DOLORES RIVER- GORE AND ELK MOUNTAINS/CENTRAL MOUNTAINS-GRAND AND BATTLEMENT MESAS- GRAND VALLEY-LA SAL AND ABAJO MOUNTAINS-LOWER YAMPA RIVER BASIN- NORTHWEST SAN JUAN MOUNTAINS-PARADOX VALLEY/LOWER DOLORES RIVER- ROAN AND TAVAPUTS PLATEAUS-SAN JUAN RIVER BASIN-SOUTHEAST UTAH- SOUTHWEST SAN JUAN MOUNTAINS-TAVAPUTS PLATEAU- UNCOMPAHGRE PLATEAU AND DALLAS DIVIDE-UPPER GUNNISON RIVER VALLEY- UPPER YAMPA RIVER BASIN-WEST ELK AND SAWATCH MOUNTAINS- 432 AM MST WED DEC 31 2003 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EASTERN UTAH AND WESTERN COLORADO. .DAY ONE...TODAY AND TONIGHT... SCATTERED SNOW SHOWERS WILL AFFECT THE MOUNTAINS OF EASTERN UTAH AND WESTERN COLORADO TODAY AND TONIGHT. IN ADDITION TO THE SNOW...GUSTY SOUTHWEST WINDS OF 20 TO 35 MPH WILL BLOW OVER EXPOSED HIGH TERRAIN. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY... SIGNIFICANT SNOWFALL WILL BE POSSIBLE LATE THURSDAY THROUGH SATURDAY WITH THE POTENTIAL FOR HEAVY SNOW AND STRONG WINDS IN THE MOUNTAINS ON FRIDAY. A COLD AIR MASS WILL FOLLOW SUNDAY AND MONDAY WITH SUB- ZERO MORNING LOW TEMPERATURES POSSIBLE FOR THE MOUNTAINS AND HIGH VALLEYS. THE CHANCE OF SNOW WILL INCREASE AGAIN ON TUESDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY OR TONIGHT. HOWEVER... SPOTTERS ARE ENCOURAGED TO REPORT THEIR LATEST SNOWFALL AND SNOW DEPTH. HEFFERNAN
In the hours before
Special weather statement, Dec 31, 5:30 AM MST, 4 hours 3 minutes before
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</html>Special weather statement, Dec 31, 5:39 AM MST, 3 hours 54 minutes before
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</html>The radar
The national radar mosaic for the moment the first event began.
Event by event
1 dense fog. Local standard time, as filed.
What these are
- Dense Fog
- Fog reducing visibility to a quarter mile or less, filed where it caused accidents or disruption.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
More
Every storm in Colorado in 2003Every state in 2003This day in weather historyWarnings in Colorado, December 2003
Sources
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 2026-09-30. Each event’s entry at NCEI: 5331688.