Dense Fog in Utah, December 30, 2002

Name: Dense Fog in Utah, December 30, 2002
Start: 2002-12-30T04:00
End: 2002-12-30T09:00
Location: Utah

December 30, 2002 · NWS GJT · 1 event in 1 county or zone

Widespread dense fog developed across the Colorado River valley in extreme east central Utah. The Canyonlands ASOS indicated visibilities below 1/4 mile.

Where it happened

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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.

Widespread dense fog developed across the Colorado River valley in extreme east central Utah. The Canyonlands ASOS indicated visibilities below 1/4 mile.

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 29, 2:26 PM MST, 13 hours 34 minutes earlier.

Area forecast discussion, Dec 29, 2:26 PM MST, 13 hours 34 minutes before

WESTERN COLORADO & EASTERN UTAH AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
226 PM MST SUN DEC 29 2002

APPROACHING STORM SYSTEM LOOKING UNORGANIZED ON SATELLITE IMAGERY.
MAIN BATCH OF ENERGY IN THE SOUTHERN PORTION OF THE TROUGH IS
TAKING A TRACK FURTHER SOUTH THAN YESTERDAY/S MODELS SUGGESTED.
STRONG SOUTH FLOW AHEAD OF THE COLD FRONT PROVIDING SOME GOOD MIXING
AND A NICE WARMUP FOR MUCH OF THE CWA. 88D VAD WINDS SHOWING 30KTS
AT 11K FEET. SEVERAL MOUNTAINS RAWS SHOWING GUSTS TO AROUND 40 MPH
ACROSS THE NORTHERN CWA. A FEW VALLEY METARS SHOWING SOME GUSTS TO
AROUND 25 MPH BUT LACK OF MIXING IS KEEPING LOWER ELEVATION WINDS
IN CHECK. COLD FRONT WILL MOVE THROUGH THE AREA LATE THIS AFTERNOON
AND EVENING WITH GUSTY WINDS CONTINUING IN THE SOUTH FLOW. BEST
SNOW FOR THE SAN JUANS BETWEEN 00Z AND 06Z WITH GOOD OROGRAPHIC LIFT
AHEAD OF UPPER TROUGH. NW CO MOUNTAINS WILL DO BETTER AS THE WINDS
VEER TO NORTHWEST THIS EVENING. EVENT SHOULD BE WINDING DOWN BY 12Z
MONDAY AS DRIER AND MORE STABLE AIR MOVES IN. DROPPED THE WINTER
WEATHER ADVISORY FOR THE MOUNTAINS EARLIER TODAY. LATEST QPF AND
OROGRAPHIC SNOW MODEL OUTPUT SUPPORT THIS IDEA WITH AMOUNTS BELOW
ADVISORY CRITERIA.

NORTHWEST FLOW GRADUALLY BACKS TO THE WEST AND SOUTHWEST MONDAY
AFTERNOON AND NIGHT AS A SHORTWAVE RIDGE MOVES THROUGH. PROGRESSIVE
FLOW BRINGS ANOTHER WAVE INTO THE AREA TUESDAY AND WEDNESDAY.
MOISTURE AND DYNAMICS LOOK A LITTLE BETTER WITH THIS SYSTEM WITH A
LONGER DURATION OF SNOW POTENTIAL. TAL

EXTENDED...THURSDAY THROUGH SUNDAY...
SEMI ZONAL AND PROGRESSIVE FLOW CONTINUES THROUGH MID WEEK. MODELS IN
GOOD AGREEMENT THROUGH THURSDAY AND THEN BEGIN TO DEVIATE AS THE
FLOW AMPLIFIES INTO THE WEEKEND. THE NEXT PACIFIC STORM FOR THIS
PERIOD IS ON TAP FOR FRIDAY AFTERNOON INTO SATURDAY. THIS SYSTEM
IS VERY SIMILAR TO THE ONE ON TUESDAY/WEDNESDAY BUT NOT AS DEEP AND
TRACKS A BIT FURTHER NORTH. CURRENT FORECAST IN LINE WITH SENSIBLE
WEATHER...SO WILL ADD SUNDAY WITH SLIGHT CHANCE OF SNOW ACCOUNTING
FOR SOME WRAP AROUND FLOW IN NORTHERN MOUNTAINS. DJC/21

.GJT...NONE.

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 dense fog. Local standard time, as filed.

Dense Fog, Grand Flat and Arches

When: December 30, 4:00 AM MST to 9:00 AM MST
Where: Grand Flat and Arches forecast zone
Reported by: AWOS,ASOS,MESONET,ETC
Coordinates: 38.982, -109.570 (the zone’s center; the record gives no point)

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

Every storm in Utah in 2002 Every state in 2002 This day in weather history Warnings in Utah, December 2002

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 2026-09-24. Each event’s entry at NCEI: 5327110.