Flash Flood, San Diego
- When
- August 26, 6:40 AM PST to 7:40 AM PST
- Where
- San Diego County, Escondido to San Pasqual
- Cause
- Heavy Rain
- Property damage
- $5,000
- Reported by
- Trained Spotter
- Coordinates
- 33.130, -117.070
Flash Flooding and Hail in California, August 26, 2007
The remnants of Hurricane Dean brought numerous thunderstorms to many areas of Southern California. Thunderstorms erupted in northern San Diego County shortly before sunrise near Escondido.
Where it happened
Every event with a place to put it. 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
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- $20,000
- Crop damage
- None recorded
- Events
- 3
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.
The remnants of Hurricane Dean brought numerous thunderstorms to many areas of Southern California. Thunderstorms erupted in northern San Diego County shortly before sunrise near Escondido. Within a couple hours, the thunderstorms had expanded along a line that extended from near Oceanside to Julian. Several spotters in Escondido reported just under 2.00 inches of rain in an hour and half. Just east of Escondido, an alert rain gage at Lake Wohlford measured 2.13 inches of rain. Some flash flooding was reported in the Escondido area.
Another cluster of thunderstorms off the coast moved onshore at San Clemente later that morning. The beach was evacuated just prior to the arrival of the storm due to frequent cloud to ground lightning. There was one report of a waterspout but that report was never confirmed.
Very large thunderstorms rapidly developed over the Anza Borrego Desert that afternoon. Radar indicated a 60k ft echo top with one of those thunderstorms. Flash flooding was reported along highway S22 east of Borrego Springs and several people were trapped in washes in the Borrego Badlands.
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 26, 3:00 AM PST, 3 hours 40 minutes earlier.
Area forecast discussion, Aug 26, 3:00 AM PST, 3 hours 40 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 400 AM PDT SUN AUG 26 2007 .SYNOPSIS... MONSOONAL MOISTURE WILL BRING A CHANCE OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND EVENING...MAINLY OVER THE MOUNTAINS AND DESERTS. OTHERWISE...PARTLY CLOUDY WEATHER WILL DOMINATE THE REST OF THE WEEKEND WITH PATCHY LOW CLOUDS AT THE COAST. RESIDUAL MID LEVEL MOISTURE IN SOUTH FLOW ALOFT COULD BRING SOME AFTERNOON CLOUDS TO THE MOUNTAINS AT TIMES FOR MONDAY THROUGH THE REST OF THE WEEK. BUILDING HIGH PRESSURE OVER ARIZONA WILL BRING TEMPERATURES A LITTLE ABOVE SEASONAL AVERAGES THE LATTER HALF OF THE WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... .SHORT TERM (TODAY THROUGH TUESDAY)... WATER VAPOR IMAGERY SHOWS A CYCLONIC CIRCULATION CENTER OFF THE COAST CENTERED NEAR 31N/121W. THIS CENTER CONTINUES TO MOVE SLOWLY NORTHWARD. SATELLITE AND RADAR IMAGERY SHOWS ENHANCED MID LEVEL CLOUDINESS AND WIDELY SCATTERED SHOWERS IN THE DIFLUENT AREA TO THE NORTH AND EAST OF THE CENTER. A FEW OF THESE SHOWERS COULD GRAZE PORTIONS OF THE OUTER COASTAL WATERS THROUGH SUNRISE. OTHERWISE... HIGHER PWS WILL REMAIN ACROSS SOUTHWEST CALIFORNIA TODAY WITH STEERING LEVEL FLOW TRANSITIONING FROM THE SOUTHEAST TO THE SOUTH. CANT RULE OUT THE POSSIBILITY OF ISOLATED THUNDERSTORMS WITH FLASH FLOOD PRODUCING RAINFALL IN THE MOUNTAINS AND ADJACENT DESERT AREAS THIS AFTERNOON THROUGH EARLY EVENING. HOWEVER...GIVEN THE SUBPAR NATURE OF THE MONSOON THIS SUMMER...NOT ENOUGH CONFIDENCE THAT THERE WILL BE SUFFICIENT COVERAGE OF ANY FLASH FLOOD PRODUCING THUNDERSTORMS TO JUSTIFY A FLASH FLOOD WATCH FOR THIS AFTERNOON AND EVENING. IF THE 12Z NKX SOUNDING SHOWS SOMETHING SIGNIFICANTLY DIFFERENT THAN EXPECTED...THE DAY SHIFT COULD RECONSIDER. NO CHANGE TO TREND FOR DRYING MONDAY AND TUESDAY WITH GREATLY REDUCED POPS FOR MONDAY AND LESS FOR TUESDAY. NAM DOES SHOW AN INCREASE IN STRATUS COVERAGE FOR TONIGHT THROUGH MONDAY MORNING....BUT BY MONDAY NIGHT AND TUESDAY IS BACK TO THE IDEA OF MINIMAL STRATUS FOR MUCH OF THE WEEK. && .LONG TERM (WEDNESDAY THROUGH SATURDAY)... HIGH PRESSURE OVER ARIZONA WILL BUILD AND EXPAND WITH TEMPERATURES RISING TO A LITTLE ABOVE SEASONAL AVERAGES. MINOR INTRUSIONS OF MID LEVEL MOISTURE FROM THE SOUTH COULD BRING SOME AFTERNOON CLOUDS TO THE MOUNTAINS AT TIMES...BUT IS MARGINAL FOR THUNDERSTORM DEVELOPMENT. LOW POPS ARE IN THE GRIDS...BUT NOT ENOUGH FOR PRECIPITATING WEATHER. && .AVIATION... 261030Z...MARINE LAYER ABOUT 1500 FT TODAY AND ABOUT 1200 FT MONDAY. BASES ABOUT 1200 FT MSL TODAY AND 900 FT MSL MON. EXPECT JUST PATCHY STRATUS AND FOG NEAR THE COAST NIGHT AND MORNING THROUGH MONDAY. LOCAL VSBY 3-5SM WITH ISOLATED BELOW 3SM ON THE MESAS IN THE MORNINGS. STRATUS WILL CLEAR OUT ABOUT 17Z AND RETURN LOCALLY ABOUT 03Z. SUBTROPICAL MOISTURE CONTINUES OVER THE AREA WITH WIDELY SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS OVER THE MOUNTAINS...DESERTS AND INLAND VALLEYS. TOPS OF THUNDERSTORMS 40K-50K. LIGHT SOUTHEAST FLOW THIS MORNING...BECOMING SOUTH TO SOUTHWEST THIS AFTERNOON THROUGH MONDAY...BECOMING WEST MONDAY AFTERNOON. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && PUBLIC...MARTIN AVIATION/MARINE...WHITLOW NWS ON THE WEB AT WEATHER.GOV/SANDIEGO
Hazardous weather outlook, Aug 26, 4:00 AM PST, 2 hours 40 minutes before
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN DIEGO CA 500 AM PDT SUN AUG 26 200 CAZ055-056-058-270100- SAN BERNARDINO COUNTY MOUNTAINS-RIVERSIDE COUNTY MOUNTAINS- SAN DIEGO COUNTY MOUNTAINS- 500 AM PDT SUN AUG 26 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR MOUNTAINS OF EXTREME SOUTHWESTERN CALIFORNIA. .DAY ONE...TODAY AND TONIGHT MONSOONAL MOISTURE WILL BRING A CHANCE OF THUNDERSTORMS THIS AFTERNOON AND EVENING. THE FLASH FLOOD POTENTIAL IS MODERATE... THUNDERSTORMS ARE EXPECTED TO DEVELOP AND ISOLATED FLASH FLOODING IS POSSIBLE. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY NO WIDESPREAD HAZARDOUS WEATHER IS EXPECTED. .SPOTTER INFORMATION STATEMENT... SKYWARN ACTIVATION IS REQUESTED FOR THIS AFTERNOON THROUGH EARLY EVENING. WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. CAZ048-050-060>062-270100- SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE- SAN DIEGO COUNTY VALLEYS-APPLE AND LUCERNE VALLEYS- COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS- 500 AM PDT SUN AUG 26 2007 THIS HAZARDOUS WEATHER OUTLOOK IS FOR DESERTS AND VALLEYS OF EXTREME SOUTHWESTERN CALIFORNIA. .DAY ONE...TODAY AND TONIGHT MONSOONAL MOISTURE WILL BRING A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON AND EVENING. THE FLASH FLOOD POTENTIAL IS LOW...THE RISK OF FLASH FLOODING IS MINIMAL. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY NO WIDESPREAD HAZARDOUS WEATHER IS EXPECTED. .SPOTTER INFORMATION STATEMENT... SKYWARN ACTIVATION IS REQUESTED FOR THIS AFTERNOON THROUGH EARLY EVENING. WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. MARTIN
The radar
The San Diego radar (KNKX), 24 km away, was scanning. The volume nearest the first event began at 14:39 UTC.
Event by event
2 flash flood, 1 hail. Local standard time, as filed.
Hail, San Bernardino
- When
- August 26, 11:53 AM PST
- Where
- San Bernardino County, Big Bear City
- Measured
- 0.75 in hail
- Reported by
- Amateur Radio
- Coordinates
- 34.270, -116.850
Flash Flood, San Diego
- When
- August 26, 12:45 PM PST to 2:38 PM PST
- Where
- San Diego County, 5 mi E of Borrego Spgs Arpt to 10 mi W of Ocotillo Wells
- Cause
- Heavy Rain
- Property damage
- $15,000
- Reported by
- Park/Forest Service
- Coordinates
- 33.180, -116.184
Very large thunderstorms with 60k ft echo tops rapidly developed over the Anza Borrego Desert during the afternoon hours. Flash flooding along highway S22 in the badlands east of Borrego Springs stranded or trapped several park visitors. On Highway 78, flash flooding was observed in and near several washes west of Ocotillo Wells. South of Highway 78, Split Mountain Road was said to be impassible due to flash flooding and debris.
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.
- Hail
- Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Tornadoes and Hail in North Dakota, August 26, 2007
- Damaging Winds and Lightning Strikes in Georgia, August 26 to 27, 2007
- Tornadoes and Hail in Minnesota, August 26, 2007
- Tornadoes and Hail in North Dakota, August 26, 2007
- Hail and Damaging Winds in North Carolina, August 26, 2007
- Flash Flooding and Damaging Winds in North Carolina, August 26, 2007
- Hail and Damaging Wind in Kansas, August 26, 2007
- Marine Thunderstorm Winds in Gulf of Mexico, August 26 to 27, 2007
- Flash Flood and Hail in California, August 26, 2007
- Hail in Utah, August 26, 2007
- Damaging Winds in South Carolina, August 26, 2007
- Hail in Louisiana, August 26, 2007
More
Every storm in California in 2007Every state in 2007This day in weather historyWarnings in California, August 2007
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: 59440, 59491, 59441.