California, 2001

Dense Fog in California, May 30 to 31, 2001

May 30 to 31, 2001 · NWS SGX · 1 event in 1 county or zone

Dense fog formed over the inland valleys. A 27 year old man drove off Interstate 8 in La Mesa and into a tree.

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 SGX wrote it up.

Dense fog formed over the inland valleys. A 27 year old man drove off Interstate 8 in La Mesa and into a tree. He was ejected from the vehicle. his body was not found until after the fog cleared the next morning.

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 San Diego, CA wrote its last area forecast discussion before the first event at May 30, 8:30 PM PST, 1 hour 30 minutes earlier.

Area forecast discussion, May 30, 8:30 PM PST, 1 hour 30 minutes before
EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CA
930 PM PDT WED MAY 30 2001

                             ...SYNOPSIS...
HIGH PRESSURE ALOFT WILL BRING HOT WEATHER TO THE INLAND
EMPIRE...THE MOUNTAINS AND DESERTS THURSDAY...WITH SOME COOLING IN
THE INLAND EMPIRE FRIDAY. THE MARINE LAYER WILL BE PERSISTENT AT THE
COAST WITH LOW CLOUDS AND AREAS OF FOG...EXTENDING INLAND AT NIGHT.
SOME COOLING WILL OCCUR OVER THE WEEKEND AS THE MARINE LAYER DEEPENS
AND A WEAK TROUGH OF LOW PRESSURE MOVES BY TO THE NORTH.

                            ...DISCUSSION...
LOW CLOUDS HAVE BEEN SURGING INLAND THIS EVENING AS ONSHORE PRESSURE
AND DENSITY GRADIENTS ARE WELL-DEFINED. THE HEAT IN THE BAY AREA HAS
RESULTED IN LOWER PRESSURES UP THERE WHICH HAVE KILLED THE NW FLOW
AROUND PT CONCEPTION...SO NO EDDY IS EXPECTED TONIGHT.
HOWEVER...WITH A MARINE LAYER DEPTH OF 1300 FEET...THAT SHOULD BE
SUFFICIENT FOR LOW CLOUDS AND FOG TO MAKE IT INTO THE SAN DIEGO
COUNTY VALLEYS AND MARGINALLY SO FOR THE FAR W AND S INLAND EMPIRE
WHERE SOME DENSE FOG COULD OCCUR...ESPECIALLY GIVEN THE DEW POINTS
OF 60 OR GREATER AND THE FACT AT LOW CLOUDS ARE ALREADY TOUCHING THE
SW CORNER OF RIVERSIDE COUNTY AND ARE NOT TOO FAR FROM THE SW TIP OF
SBD COUNTY. IT IS A GIVEN THAT LOW CLOUDS WILL NOT CLEAR VERY MANY
COASTAL AREAS...IF ANY...AS THE INVERSION STRENGTH SHOULD BE GREATER
THAN 10 DEG C.

IN THE UPDATE...I HAVE PULLED BACK A BIT WITH TEMPS DUE TO THE
MARINE LAYER...THOUGH THE AREAS ADJACENT TO THE FOOTHILLS IN THE
INLAND EMPIRE SHOULD STILL BE OVER 100 THURSDAY. ONSHORE FLOW
INCREASES BOTH AT THE SURFACE AND AT 850 MB FRIDAY FOR WIDESPREAD
COOLING...ESPECIALLY IN THE VALLEYS. ONCE THE HEAT WANES IN THE BAY
AREA...WHICH WILL OCCUR ABRUPTLY FRIDAY...WE WILL BE ABLE TO RESUME
NW FLOW AROUND PT CONCEPTION...AND THAT WILL COMBINE WITH MORE
EDDY-FRIENDLY 850 MB WINDS TO ALLOW THE EDDY TO REDEVELOP OVER THE
WEEKEND AND BRING COOL WEATHER WITH EXTENSIVE LOW CLOUDS OVER THE
WEEKEND. THE DESERTS SHOULD COOL ONLY SLIGHTLY AS THE TROUGH WILL
MOSTLY REMAIN TO THE NORTH.

SAN 0000

.SAN...NONE.

MAXWELL

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, San Diego County Valleys

When
May 30, 10:00 PM PST to May 31, 7:00 AM PST
Where
San Diego County Valleys forecast zone
Reported by
NEWSPAPER
Coordinates
33.028, -116.770 (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

More

Every storm in California in 2001Every state in 2001This day in weather historyWarnings in California, May 2001

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: 5243338.