Dense Fog in California, December 31, 2003

Name: Dense Fog in California, December 31, 2003
Start: 2003-12-31T02:16
End: 2003-12-31T23:35
Location: California

December 31, 2003 · NWS HNX · 4 events in 4 counties and zones

Dense fog formed in the Central and Southern San Joaquin Valley on the morning of the 31st hindering traffic movement with visibilities lowered to less than 1000 feet. Dense fog reformed briefly and then dissipated in the evening of the 31st in the Southern San Joaquin Valley.

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 4

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 HNX wrote it up.

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 Hanford, CA wrote its last area forecast discussion before the first event at Dec 30, 8:50 PM PST, 5 hours 26 minutes earlier.

Area forecast discussion, Dec 30, 8:50 PM PST, 5 hours 26 minutes before

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Event by event

4 dense fog. Local standard time, as filed.

Dense Fog, E Central S.J. Valley

When: December 31, 2:16 AM PST to 9:00 AM PST
Where: E Central S.J. Valley forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

Dense Fog, Se S.J. Valley

When: December 31, 3:35 AM PST to 11:35 PM PST
Where: Se S.J. Valley forecast zone
Reported by: LAW ENFORCEMENT

Dense Fog, Sw S.J. Valley

When: December 31, 4:19 AM PST to 10:35 PM PST
Where: Sw S.J. Valley forecast zone
Reported by: AWOS,ASOS,MESONET,ETC

Dense Fog, W Central S.J. Valley

When: December 31, 5:30 AM PST to 9:00 AM PST
Where: W Central S.J. Valley forecast zone
Reported by: OFFICIAL NWS OBS.

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 California in 2003 Every state in 2003 This day in weather history Warnings in California, 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 2026-10-01. Each event’s entry at NCEI: 5332370, 5332372, 5332371, 5332369.