Name: Flash Flooding in California, August 1, 2003
Start: 2003-08-01T18:07
End: 2003-08-01T20:00
Location: California

Where it happened

Every event with a place to put it; 2 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: None recorded
Crop damage: None recorded
Events: 2

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.

Excessive rainfall rates of over 1 inch per hour from late summer monsoon thunderstorm activity led to flooding events at several locations in the mountains of Kern County. Moist antecedent conditions existed as thunderstorms with estimated rainfall amounts of 3-6 inches had tracked over the area the previous evening (the 31st of July).

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 Aug 1, 12:55 PM PST, 5 hours 12 minutes earlier.

Area forecast discussion, Aug 1, 12:55 PM PST, 5 hours 12 minutes before

INTERIOR CENTRAL CALIFORNIA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HANFORD CA
155 PM PDT FRI AUG 1 2003

MAIN FORECAST CONCERN CONTINUES TO BE THE THUNDERSTORMS AND THE
POTENTIAL FOR HEAVY RAIN THE REMAINDER OF THIS AFTERNOON AND THIS
EVENING. A LARGE CLOUD MASS COVERS MUCH THE EASTERN CA DESERTS AND
THE SIERRA NEVADA THIS AFTERNOON. THUNDERSTORMS HAVE BEGUN
DEVELOPING ALONG THE WESTERN EDGE IN THE INTERFACE BETWEEN THE VERY
MOIST AIR AND THE LESS MOIST AIR FROM KERN COUNTY SOUTHWARD. WITH
PRECIPITAL WATER VALUES AROUND 1.2 INCHES AND RATHER LIGHT STEERING
WINDS WILL CONTINUE WITH FLASH FLOOD WATCH FOR THE KERN COUNTY
MOUNTAINS AND DESERT. HOWEVER...WITH THUNDERSTORMS EXPECTED TO
CONTINUE THROUGH THE EVENING HOURS...WILL EXTEND WATCH UNTIL 9 PM.

UPPER LOW OFF THE SRN CA COAST EXPECTED TO MOVE SLOWLY NORTHWARD
SATURDAY...WHILE UPPER HIGH OVER UT AND NM SHIFTS FARTHER EAST. THE
CORRESPONDING UPPER LEVEL FLOW SHIFTS TO MORE OF A SOUTH DIRECTION
SATURDAY. BUT WITH THE UPPER LOW BRINGING A VORTMAX OVER CENTRAL
CA...AND PLENTY OF MOISTURE REMAINING...CONVECTION MAY NOT BE
LIMITED TO THE SIERRA NEVADA. HAVE ADDED SLIGHT CHANCE POPS TO THE
VALLEY AND FOOTHILL ZONES FOR SATURDAY AND HAVE INCREASED THE POPS
IN THE MOUNTAIN ZONES SLIGHTLY. THE FLOW ALOFT FINALLY BECOMES
SOUTHWESTERLY SUNDAY AS AN UPPER TROUGH IN THE PACIFIC MOVES
NORTHEAST AND SETS ITSELF UP ALONG THE PACNW COAST. THIS WILL SHUT
OFF THE CONVECTIVE THREAT FOR ALL BUT THE SIERRA CREST SUNDAY.

IN THE EXTENDED PERIOD...TUE THRU FRI...LONG RANGE MODELS IN VERY
GOOD AGREEMENT IN THE 4 TO 6 DAY PERIOD WITH LONG WAVE TROUGH
POSITIONED OFF THE WEST COAST AND UPPER LEVEL RIDGE CENTERED ALONG
THE CONTINENTAL DIVIDE. IMPRESSIVE ONSHORE GRADIENTS DURING MIDWEEK
WOULD CONTINUE TO BRING REINFORCING MARINE PUSHES INTO THE SJ VLY IN
ADDITION TO SYNOPTIC COOLING OVER THE HIGHER ELEVATIONS. IN
ADDITION...WESTERLY WINDS MAY BE LOCALLY GUSTY THRU AND BELOW THE
MOUNTAIN PASSES OF KERN COUNTY DURING MIDWEEK AS WELL AS THE WEST
SIDE OF THE SJ VLY. TEMPS LIKELY TO AVERAGE A FEW DEGREES BELOW
NORMAL IN MOST AREAS. THE LATEST RUN OF THE GFS FORECASTS 850 MB
TEMPS TO COOL INTO THE MIDDLE TEENS (CELSIUS) OVER THE NORTHWEST
PORTION OF THE CWA BY TUE AFTN AND WED AFTN. SUPPLEMENTED WITH A
BRISK ONSHORE FLOW...MAX TEMPS COULD CONCEIVABLY BE ONLY 78 OR 79
DEGREES ON DAYS 3 AND 4 IN WESTERN MERCED CO. EVEN IN THE KERN CO
DESERT...TEMPS MAY PEAK JUST UNDER 90 DEGREES IN PLACES LIKE MOJAVE
BY WED. A WARMING TREND WILL BEGIN THURSDAY AND CONTINUE FRIDAY AS
UPPER LEVEL HIGH BUILDS WESTWARD TOWARD CA. BY FRI PM...THE GFS
WARMS 850 MB TEMPS INTO THE LOWER TO MID 20S (CELSIUS) ACROSS
INTERIOR CENTRAL CA...THUS NUDGING TEMPS TO NORMAL OR SLIGHTLY ABOVE
NORMAL BY THE CLOSE OF THE WORK WEEK. THE GFS GIVES NO INDICATION
THAT THE MONSOON WILL RETURN TO CENTRAL CA BY DAY 7...SO WILL KEEP
THE FORECAST DRY THROUGH THE EXTENDED PERIOD.

.HNX...FLASH FLOOD WATCH THIS EVENING FOR THE KERN COUNTY MOUNTAINS
AND DESERTS (ZONES 95, 98-99).

BEAN/DURFEE

Hazardous weather outlook, Aug 1, 3:30 PM PST, 2 hours 37 minutes before

CAZ089>099-021230-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY - HANFORD CA
430 PM PDT FRI AUG 1 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE CENTRAL CALIFORNIA
INTERIOR.

.DAY ONE...TODAY

SCATTERED THUNDERSTORMS WILL CONTINUE TO DEVELOP OVER THE KERN
COUNTY MOUNTAINS AND DESERTS THIS AFTERNOON AND EVENING. SOME OF THE
STORMS WILL PRODUCE VERY HEAVY RAINFALL LEADING TO POSSIBLE FLASH
FLOODING. A FLASH FLOOD WATCH HAS BEEN ISSUED THROUGH 900 PM. REFER
TO FFAHNX /WGUS66 KHNX/ FOR DETAILS.

THERE IS ALSO A CHANCE FOR THUNDERSTORMS OVER THE REMAINDER OF THE
CENTRAL CALIFORNIA INTERIOR. ANY THUNDERSTORMS MAY CONTAIN BRIEF
HEAVY RAIN...GUSTY WINDS...AND DANGEROUS LIGHTNING.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS TO THEIR LOCAL NATIONAL WEATHER SERVICE OFFICE.

JEB

In the hours before

Local storm report, Aug 1, 4:03 PM PST, 2 hours 4 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SAN JOAQUIN VALLEY CA
0503 PM PDT FRI AUG 01 2003

TIME(PDT)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0409 PM    LAKE ISABELLA             CA   FLOOD
08/01/03   KERN                           1.24 RAIN IN 2 HOURS GAVE
                                          STREET FLOODING

GUDGEL

The radar

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

Open the radar archive at this moment

Event by event

2 flash flood. Local standard time, as filed.

Flash Flood, Kern

When: August 1, 6:07 PM PST to 8:00 PM PST
Where: Kern County, 5 mi NE of Loraine
Reported by: EMERGENCY MANAGER
Coordinates: 35.343, -118.730 (the zone’s center; the record gives no point)

Flash Flood, Kern

When: August 1, 6:07 PM PST to 8:00 PM PST
Where: Kern County, 9 mi WSW of Tehachapi
Reported by: EMERGENCY MANAGER
Coordinates: 35.343, -118.730 (the zone’s center; the record gives no point)

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

More

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: 5333435, 5333436.