Utah, 2024

Dense Fog in Utah, December 28, 2024

December 28, 2024 · NWS GJT · 1 event in 1 county or zone

The unsettled pattern that characterized the last week of the month of December brought widespread precipitation to eastern Utah and western Colorado with regularity. This precipitation created pools of rich low level moisture trapped in the lower elevation valleys across the region.

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.

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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.

The unsettled pattern that characterized the last week of the month of December brought widespread precipitation to eastern Utah and western Colorado with regularity. This precipitation created pools of rich low level moisture trapped in the lower elevation valleys across the region. As skies cleared and temperatures cooled each night, dense fog then developed in each of these valleys, often widespread. Thanks to the low sun angle, this fog would linger well into the daylight hours before finally lifting.

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 28, 6:13 AM MST, 3 hours 32 minutes earlier.

Area forecast discussion, Dec 28, 6:13 AM MST, 3 hours 32 minutes before
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Hazardous weather outlook, Dec 28, 4:34 AM MST, 5 hours 11 minutes before
Hazardous Weather Outlook
National Weather Service Grand Junction CO
434 AM MST Sat Dec 28 2024

COZ001>014-017>023-UTZ022>025-027>029-291145-
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-
434 AM MST Sat Dec 28 2024

This Hazardous Weather Outlook is for northwest Colorado, southwest
Colorado, west central Colorado, east central Utah, northeast Utah
and southeast Utah.

.DAY ONE...Today and tonight.

High levels of near surface moisture have resulted in areas of fog,
locally dense in some locations, which will persist well into the
morning. Snow will increase again today as the latest disturbance
moves over the area this afternoon through tonight. Significant
snowfall amounts are expected with many mountain areas seeing from 4
to 8 inches with locally higher amounts, and from 8 to 14 inches
with locally higher amounts in the northern mountains.

.DAYS TWO THROUGH SEVEN...Sunday through Friday.

Several clippers in the northwest flow will bring additional snow off
and on over the northern and central Colorado mountains through
Friday. Atmospheric moisture will be decreased so aside from Sunday
night into Monday, additional snowfall amounts will be relatively
light as compared to the past several days.

.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.

In the hours before

Local storm report, Dec 28, 7:26 AM MST, 2 hours 19 minutes before
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Local storm report, Dec 28, 8:45 AM MST, 1 hour before
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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, Eastern Uinta Basin

When
December 28, 9:45 AM MST to 12:00 PM MST
Where
Eastern Uinta Basin forecast zone
Reported by
ASOS
Coordinates
40.125, -109.518 (the zone’s center; the record gives no point)

At around 9:45AM local time, the KVEL ASOS began reporting visibilities of less than 1/2 mile. Satellite imagery, and road cameras provided by the Utah Department of Transportation confirmed the widespread nature of the dense fog in and around the more populated parts of the eastern Uinta Basin. The fog began to lift around 12PM local time. No reports of injuries, damages, or fatalities were received.

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 Utah in 2024Every state in 2024This day in weather historyWarnings in Utah, December 2024

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: 1226698.