Wildfire in California, August 20, 2003

Name: Wildfire in California, August 20, 2003
Start: 2003-08-20T15:45
End: 2003-08-20T18:36
Location: California

August 20, 2003 · NWS SGX · 1 event in 1 county or zone

Named the Mormon Rocks Fire, it burned 10 acres and caused Highway 138 to be closed for about one hour. Property damage was confined to a power line.

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

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $20,000
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.

Named the Mormon Rocks Fire, it burned 10 acres and caused Highway 138 to be closed for about one hour. Property damage was confined to a power line.

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 Aug 20, 1:30 PM PST, 2 hours 15 minutes earlier.

Area forecast discussion, Aug 20, 1:30 PM PST, 2 hours 15 minutes before

EXTREME SOUTHWESTERN CALIFORNIA AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SAN DIEGO CALIFORNIA
230 PM PDT WED AUG 20 2003

.SYNOPSIS...MONSOONAL MOISTURE WILL BRING THUNDERSTORMS TO THE
MOUNTAINS AND DESERTS THROUGH FRIDAY...MAINLY DURING THE AFTERNOON
AND EARLY EVENING...AND DECREASE OVER THE WEEKEND. OTHERWISE...SKIES
WILL BE PARTLY CLOUDY AT TIMES WITH ONLY PATCHY LOW CLOUDS AT THE
COAST. TEMPERATURES WILL BE SEASONAL WITH SOME DECREASE IN HUMIDITY
OVER THE WEEKEND. THE CHANCE OF MOUNTAIN THUNDERSTORMS WILL CONTINUE
NEXT WEEK.

.DISCUSSION...CONVECTION STARTED UP IN THE LATE MORNING AS EXPECTED
AND FLOODING TSTORMS ARE ALL OVER THE MTNS AND DESERTS. WARNINGS AND
WATCHES WILL DETAIL THOSE AREAS. A VERY MOIST AND UNSTABLE
ENVIRONMENT WILL KEEP SOME TSTORMS GOING INTO THIS EVE. THE TSTORMS
SHOULD END OVERNIGHT AS THE DYNAMICS MOVE OUT AND THE SUN GOES DOWN.
MOISTURE DECREASES SLOWLY THU THROUGH FRI SO TSTORMS WILL NOT BE SO
WIDESPREAD...BUT STILL POSSIBLE IN MTNS AND ADJACENT DESERTS.
COASTAL CLOUDS WILL BE MINIMAL AT BEST...BUT THE CLOUD DECK IS NOT
DISRUPTED YET BY THESE OTHER FORCES...SO WILL KEEP THEM IN THE
COASTAL AREAS. THE MOISTURE REACHES ITS MINIMUM OVER THE WEEKEND AS
THE UPPER HIGH MOVES EASTWARD AND FLOW TURNS SOUTHWEST. THEN
INCREASES AGAIN MON AND BEYOND AS THE UPPER HIGH BUILDS WESTWARD
AGAIN. SOME MENTION OF MTN TSTORMS WILL BE IN THE EXTENDED FORECAST.
TEMPS WILL NOT CHANGE MUCH.

SAN...FLASH FLOOD WATCH AND WARNING...SEE LAXFLSSGX.

Hazardous weather outlook, Aug 20, 5:00 AM PST, 10 hours 45 minutes before

FLUS46 KSGX 181011
HWOSGX
CAZ042-043-048-050-055>058-060>062-211300-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN DIEGO CA
600 AM PDT WED AUG 20 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR
EXTREME SOUTHWESTERN CALIFORNIA.

.DAY ONE... TODAY THROUGH TONIGHT

FLASH FLOOD WATCH FOR THE MOUNTAINS AND DESERTS FOR
THIS AFTERNOON AND EVENING.

SKYWARN ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.

.DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY

CHANCE OF THUNDERSTORMS OVER THE MOUNTAINS AND DESERTS EACH
AFTERNOON AND EVENING. COVERAGE WILL BE LEAST OVER THE WEEKEND.

The radar

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

Open the radar archive at this moment

Event by event

1 wildfire. Local standard time, as filed.

Wildfire, San Bernardino

When: August 20, 3:45 PM PST to 6:36 PM PST
Where: San Bernardino County, Cajon
Property damage: $20,000
Reported by: NEWSPAPER
Coordinates: 34.841, -116.178 (the zone’s center; the record gives no point)

What these are

Wildfire: A fire burning in wildland vegetation, with its acreage and damage where known.

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, August 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 2026-09-24. Each event’s entry at NCEI: 5369453.