66" of rain in 11 minutes in San Felipe Valley. The heavy rain resulted in a rock slide and flash flooding on highway 78 just east of Yaqui Pass.
Every event with a place to put it; 3 filed by county or forecast zone are drawn at its center, in a lighter ring. Tap one for its entry below.
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.
The episode as NWS SGX wrote it up.
A line of thunderstorms dropped 0.63" of rain in 8 minutes just northeast of Julian over Volcan Mountain and 0.66" of rain in 11 minutes in San Felipe Valley. The heavy rain resulted in a rock slide and flash flooding on highway 78 just east of Yaqui Pass. The road was closed for several hours.
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 13, 9:20 AM PST, 3 hours 24 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO 1020 AM PDT FRI AUG 13 2004 .SYNOPSIS...MONSOON FLOW WILL CONTINUE TO BRING CHANCES OF THUNDERSTORMS THROUGH SATURDAY...WITH MOST OF THE ACTIVITY IN THE MOUNTAINS AND DESERTS. A WEAK UPPER TROUGH WILL BUILD SUNDAY AND MONDAY BRINGING COOLER WEATHER AND A DEEPER MARINE LAYER. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES. OUTFLOW BOUNDARY FROM MCS OVER THE INLAND EMPIRE THIS MORNING MOVED NORTH AND TRIGGERED CONVECTION OVER THE SAN BERNARDINO COUNTY MTNS. ANTICIPATED HEAVY RAINFALL RATES IN THE OROGRAPHIC FAVORED SLOPES PROMPTED A FLASH FLOOD WARNING. 1.50 INCHES OF RAIN FELL AT OAK GLEN IN 30 MINUTES. FARTHER SOUTH THE SKIES WERE CLEAR OVER SAN DIEGO COUNTY. AIRMASS QUITE MOIST WITH A PW OF 1.50 ON THE 12Z NKX SOUNDING. DAYTIME HTG WAS ALREADY PRODUCING CONVECTIVE CLOUDS OVER NORTHERN BAJA...WHERE CAPE VALUES WERE ALREADY NEAR 1000 J/KG. SATURDAY LOOKS LIKE IT WILL HAVE QUITE A BIT OF LINGERING MOISTURE SO WILL KEEP THE CHANCES FOR PRECIP GOING TOMORROW. ...NO CHANGES TO REST OF DISCUSSION... GFS HAS MARGINALLY ENOUGH MOISTURE FOR TSTORMS FOR SUNDAY...BUT THE WEST WINDS WILL WORK TO MAKE THINGS DRIER AND MORE STABLE...SO I WILL KEEP SUNDAY DRY FOR NOW. THE MARINE LAYER SHOULD GRADUALLY INCREASE OVER THE WEEKEND AND ALLOW FOR MORE NOCTURNAL PENETRATION OF THE LOW CLOUDS. THE EXTENDED IS RATHER TRICKY SINCE THE RECENT TREND HAS BEEN FOR LESS TROUGHING OFF THE COAST. SO...FOR EARLY NEXT WEEK...THERE WILL BE LITTLE CHANGE IN TEMP AND PROBABLY NO TSTORMS. RIGHT NOW...THE MODELS HAVE THE HIGHEST HEIGHTS AT 500 MB TO OUR SOUTH...BUT THE 500 MB GRADIENTS ARE SO MINIMAL THAT A SMALL CHANGE IN THE 500 MB FLOW COULD BRING A BIG CHANGE WEATHERWISE...ESPECIALLY WITH REGARDS TO TSTORMS. .SGX WATCHES/WARNINGS/ADVISORIES...NONE. && MAXWELL/MOEDE
HAZARDOUS WEATHER OUTLOOK...UPDATE NATIONAL WEATHER SERVICE SAN DIEGO CA 630 AM PDT FRI AUG 13 2004 CAZ042-043-048-057-141300- ORANGE COUNTY COASTAL AREAS- SAN DIEGO COUNTY COASTAL AREAS- SAN BERNARDINO COUNTY AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE- SANTA ANA MOUNTAINS AND FOOTHILLS- 630 AM PDT FRI AUG 13 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ORANGE COUNTY...THE SAN DIEGO COUNTY COASTAL AREAS AND THE INLAND EMPIRE. .DAY ONE... TODAY THROUGH TONIGHT. MOISTURE IN SOUTHERLY FLOW ALOFT WILL CAUSE ISOLATED THUNDERSTORMS TODAY. THUNDERSTORMS HAVE DEADLY LIGHTNING AND MAY HAVE BRIEF HEAVY RAIN...STRONG GUSTY WINDS AND HAIL. .DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY. NO HAZARDOUS WEATHER IS EXPECTED. CAZ050-141300- SAN DIEGO COUNTY VALLEYS- 630 AM PDT FRI AUG 13 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE SAN DIEGO COUNTY VALLEYS .DAY ONE... TODAY THROUGH TONIGHT. FLASH FLOOD WATCH UNTIL 800 PM. MOISTURE IN SOUTHERLY FLOW ALOFT WILL CAUSE SCATTERED THUNDERSTORMS TODAY. THUNDERSTORMS HAVE DEADLY LIGHTNING AND WILL HAVE BRIEF HEAVY RAIN...STRONG GUSTY WINDS AND HAIL. HEAVY RAIN COULD CAUSE FLOODING AND MUD SLIDES...ESPECIALLY IN THE RECENTLY BURNED AREAS. .DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY. NO HAZARDOUS WEATHER IS EXPECTED. CAZ055-056-058-060-061-062-141300- SAN BERNARDINO COUNTY MOUNTAINS- RIVERSIDE COUNTY MOUNTAINS- SAN DIEGO COUNTY MOUNTAINS- APPLE AND YUCCA VALLEYS- COACHELLA VALLEY- SAN DIEGO COUNTY DESERTS- 630 AM PDT FRI AUG 13 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR THE MOUNTAINS AND DESERTS OF EXTREME SOUTHWESTERN CALIFORNIA. .DAY ONE... TODAY THROUGH TONIGHT. FLASH FLOOD WATCH UNTIL 800 PM. MOISTURE IN SOUTHERLY FLOW ALOFT WILL CAUSE SCATTERED THUNDERSTORMS IN THE MOUNTAINS AND DESERTS TODAY INTO THIS EVENING. THUNDERSTORMS HAVE DEADLY LIGHTNING AND WILL HAVE BRIEF HEAVY RAIN...STRONG GUSTY WINDS AND HAIL. HEAVY RAIN COULD CAUSE FLOODING AND MUD SLIDES...ESPECIALLY IN THE RECENTLY BURNED AREAS. .DAYS TWO THROUGH SEVEN... SATURDAY THROUGH THURSDAY. MOIST UNSTABLE AIR WILL CONTINUE ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS IN THE MOUNTAINS AND DESERTS SATURDAY AFTERNOON. THUNDERSTORMS HAVE DEADLY LIGHTNING AND MAY HAVE BRIEF HEAVY RAIN...STRONG GUSTY WINDS AND HAIL. LOCAL HEAVY RAIN COULD CAUSE FLOODING AND MUD SLIDES...ESPECIALLY IN THE RECENTLY BURNED AREAS. DRIER SOUTHWEST FLOW ALOFT WILL DEVELOP EARLY NEXT WEEK. MAXWELL
The San Diego radar (KNKX), 28 km away, was scanning. The volume nearest the first event began at 20:45 UTC.
2 heavy rain, 1 flash flood. Local standard time, as filed.
A line of thunderstorms dropped 0.66" in 11 minutes in San Felipe Valley.
A line of thunderstorms just northeast of Julian dropped 0.63" of rain in only eight minutes on Volcan Mountain.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2004Every state in 2004This day in weather historyWarnings in California, August 2004
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: 5418561, 5418560, 5418562.