A weak easterly wave brought widespread showers and thunderstorms to Southern California with mostly light to moderate rainfall, but heavy in spots. Easterly flow also helped to bring the rainfall to the coast.
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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 weak easterly wave brought widespread showers and thunderstorms to Southern California with mostly light to moderate rainfall, but heavy in spots. Easterly flow also helped to bring the rainfall to the coast. Very heavy rainfall and gusty winds were reported in San Diego, Riverside and San Bernardino Counties.
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 Jul 15, 8:30 AM PST, 4 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 930 AM PDT THU JUL 15 2010 .SYNOPSIS...STRONG HIGH PRESSURE ALOFT WILL BRING HOT DAYS INLAND THROUGH THE WEEKEND. SCATTERED THUNDERSTORMS ARE EXPECTED OVER THE MOUNTAINS AND DESERTS THIS AFTERNOON AND EVENING...WITH A FEW STORMS POSSIBLY DRIFTING INTO THE INLAND VALLEYS OR SAN DIEGO COASTAL AREAS. ONLY A FEW THUNDERSTORMS ARE EXPECTED OVER AND NEAR THE MOUNTAINS FRIDAY THROUGH SUNDAY AS MID LEVEL MOISTURE DECREASES. AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL BRING COOLING AND THE RETURN OF THE MARINE LAYER CLOUDS TO COASTAL AREAS NEXT WEEK. && .DISCUSSION...FOR SOUTHWEST CALIFORNIA INCLUDING SAN DIEGO... ORANGE...SOUTHWEST SAN BERNARDINO AND WEST RIVERSIDE COUNTIES. .SHORT TERM (REMAINDER OF TODAY-SUNDAY)...SKIES WERE MOSTLY CLEAR THIS MORNING BUT MID LEVEL CLOUDS WERE APPROACHING FROM THE SE. THE 12Z NKX SOUNDING WAS MOIST AND UNSTABLE WITH A PW OF 1.72 INCHES AND SE WINDS TO ABOUT 20 KTS NEAR 10000 FT. WEAK OFFSHORE GRADIENTS FROM THE N AND ONSHORE TO THE E WITH ABOUT 4 MB SAN-IPL. THE STRONG UPPER HIGH WILL CONTINUE TO BUILD AND MOVE IN FROM THE E TROUGH SATURDAY AND THEN WEAKEN A LITTLE SUNDAY AS A TROUGH APPROACHES FROM THE NW. THIS WILL BRING HOT WEATHER...ESPECIALLY INLAND. MAX TEMPS WILL BE ABOUT 5 TO 10 DEGREES ABOVE SEASONAL AVERAGES THROUGH SATURDAY. MID LEVEL CLOUDS MAY TAKE A COUPLE DEGREES OFF THE HIGHS IN THE DESERTS TODAY BUT HUMIDITY WILL MAKE IT FEEL JUST AS HOT. IT WILL BE CLOSE TO HEAT WARNING CRITERIA IN THE LOW DESERTS BUT WILL LIKELY NOT QUITE GET HEAT INDICES OF 115 DURING THE DAY AND 90 AT NIGHTS OVER A WIDESPREAD AREA FOR 3 HOURS OR MORE. A LITTLE COOLER IN MOST AREAS SUNDAY...MAINLY MAINLY NEAR THE COAST. HOWEVER...IT WILL STILL BE HOT INLAND SUNDAY. LITTLE OR NOT STRATUS IS EXPECTED THROUGH SATURDAY. A SHALLOW MARINE LAYER MAY REDEVELOP BY LATE SATURDAY NIGHT AND SUNDAY MORNING WITH AREAS OF LOW CLOUDS AND FOG NEAR THE COAST. FOG MAY BE LOCALLY DENSE WHEN THE MARINE CLOUDS RETURN. A WEAK ELY WAVE WILL BRING MORE MID LEVEL MOISTURE TODAY RESULTING IN MORE WIDESPREAD SHOWERS AND THUNDERSTORMS. THE BEST CHANCE OF THUNDERSTORMS WILL BE IN THE MOUNTAINS AND ADJACENT DESERTS BUT A FEW STORMS COULD DRIFT OVER THE INLAND VALLEYS. FLASH FLOODING WILL BE THE MAIN THREAT TODAY IN THE MOUNTAINS AND DESERTS BUT THE RISK IS NOT HIGH ENOUGH FOR A FLASH FLOOD WATCH. THERE WILL ALSO BE A SMALL CHANCE OF LIGHT SHOWERS GETTING TO THE SAN DIEGO COASTAL AREAS TODAY. THE MID LEVEL MOISTURE WILL DECREASE FRIDAY AND SATURDAY WHICH WILL MOSTLY CONFINE ANY CHANCE OF THUNDERSTORMS TO THE MOUNTAINS AND LOCALLY INTO THE DESERTS. && .LONG TERM (MONDAY-THURSDAY)...UPPER TROUGHING WILL BRING DRIER SW FLOW ALOFT...COOLING AND STRONGER ONSHORE FLOW. THERE COULD STILL BE ENOUGH RESIDUAL MID LEVEL MOISTURE FOR AFTERNOON CU OVER THE MOUNTAINS MONDAY. THE MARINE LAYER WILL DEEPEN WITH LOW CLOUDS AND FOG IN THE COASTAL AREAS AND WRN SAN DIEGO INLAND VALLEYS DURING THE NIGHTS AND MORNINGS. && .AVIATION... 151630Z...MOSTLY CLEAR EARLY. AN EASTERLY WAVE AND ASSOCIATED SHOWERS AND THUNDERSTORMS WILL MOVE OVER THE AREA WITH A CHANCE OF SHOWERS AND THUNDERSTORMS INLAND VALLEYS EASTWARD...AND A SLIGHT CHANCE SOUTHERN COASTAL AREAS. THUNDERSTORM BASES AROUND 8000-10000 FEET MSL WITH TOPS TO AROUND 35000 FEET MSL. LOCALLY GUSTY WINDS NEAR THUNDERSTORMS. LESS MOISTURE FRIDAY WITH A LOWER POTENTIAL FOR THUNDERSTORMS. SMALL && .SGX WATCHES/WARNINGS/ADVISORIES... SPECIAL WEATHER STATEMENT FOR THE HEAT. SEE LAXSPSSGX. && PUBLIC...ATKIN AVIATION...SMALL
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE SAN DIEGO CA 400 AM PDT THU JUL 15 2010 CAZ042-043-048-050-057-161200- ORANGE COUNTY COASTAL AREAS-SAN DIEGO COUNTY COASTAL AREAS- SAN BERNARDINO AND RIVERSIDE COUNTY VALLEYS-THE INLAND EMPIRE- SAN DIEGO COUNTY VALLEYS-SANTA ANA MOUNTAINS AND FOOTHILLS- 400 AM PDT THU JUL 15 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR COASTAL AND VALLEY AREAS OF EXTREME SOUTHWESTERN CALIFORNIA. .DAY ONE...TONIGHT HOT TODAY INLAND FROM THE COAST WITH HIGHS FROM 100 TO 109 IN THE INLAND EMPIRE AND 97 TO 102 IN THE FAR INLAND SAN DIEGO COUNTY VALLEYS. ISOLATED THUNDERSTORMS WILL BE POSSIBLE IN THE VALLEYS THIS AFTERNOON AND EARLY EVENING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY HOT DAYS INLAND FROM THE COAST FRIDAY THROUGH SATURDAY WITH HIGHS FROM 96 TO 106 IN THE VALLEYS. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EARLY EVENINGDUE TO THUNDERSTORM ACTIVITY IN THE MOUNTAINS. CAZ055-056-058-060-161200- SAN BERNARDINO COUNTY MOUNTAINS-RIVERSIDE COUNTY MOUNTAINS- SAN DIEGO COUNTY MOUNTAINS-APPLE AND LUCERNE VALLEYS- 400 AM PDT THU JUL 15 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR MOUNTAINS AND UPPER DESERTS OF EXTREME SOUTHWESTERN CALIFORNIA. .DAY ONE...TODAY AND TONIGHT HOT TODAY WITH SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. IN SAN BERNARDINO AND RIVERSIDE COUNTIES...THE FLASH FLOOD POTENTIAL INDEX IS LOW. THE RISK OF FLASH FLOODING IS MINIMAL. IN SAN DIEGO COUNTY MOUNTAINS...THE FLASH FLOOD POTENTIAL INDEX IS MODERATE. THUNDERSTORMS ARE EXPECTED TO DEVELOP AND ISOLATED FLASH FLOODING IS POSSIBLE. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY FOR FRIDAY THROUGH SUNDAY...HOT DAYS WITH ISOLATED AFTERNOON AND EVENING THUNDERSTORMS. THE FLASH FLOOD POTENTIAL INDEX IS LOW. THE RISK OF FLASH FLOODING IS MINIMAL. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EARLY EVENING. CAZ061-062-161200- COACHELLA VALLEY-SAN DIEGO COUNTY DESERTS- 400 AM PDT THU JUL 15 2010 THIS HAZARDOUS WEATHER OUTLOOK IS FOR LOWER DESERTS OF EXTREME SOUTHWESTERN CALIFORNIA. .DAY ONE...TODAY AND TONIGHT VERY HOT WITH DAYTIME HIGHS 111 TO 115...AND OVERNIGHT LOWS 85 TO 90. THERE IS A SLIGHT CHANCE OF AFTERNOON AND EARLY EVENING THUNDERSTORMS. THE FLASH FLOOD POTENTIAL INDEX IS LOW. THE RISK OF FLASH FLOODING IS MINIMAL. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY FOR FRIDAY THROUGH SUNDAY...VERY HOT WITH DAYTIME HIGHS FROM 112 TO 117 EACH DAY...AND OVERNIGHT LOWS FROM 85 TO 90. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EARLY EVENING...MAINLY DUE TO THUNDERSTORM ACTIVITY IN THE MOUNTAINS. MAXWELL
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
1228 PM PDT THU JUL 15 2010
CAZ050-058-152030-
SAN DIEGO COUNTY VALLEYS CA-
SAN DIEGO COUNTY MOUNTAINS CA-
1228 PM PDT THU JUL 15 2010
...SIGNIFICANT WEATHER ADVISORY FOR SOUTHERN SAN DIEGO COUNTY UNTIL
130 PM PDT...
AT 1227 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR WAS TRACKING
A STRONG THUNDERSTORM 24 MILES SOUTHEAST OF TECATE...MOVING NORTH AT
15 MPH.
AREAS AFFECTED BY THIS STORM INCLUDE...LA MESA...MOUNT LAGUNA...PINE
VALLEY...ALPINE...RANCHO SAN DIEGO...TIERRA DEL SOL...LIVE OAK
SPRINGS...BOULEVARD...CAMPO...MORENA VILLAGE...POTRERO...TECATE...
DESCANSO...DULZURA...CUYAMACA PEAK...HARBISON CANYON...JAMUL...
GRANITE HILLS AND CASA DE ORO-MOUNT HELIX.
THE STORM HAS A POTENTIAL FOR HAIL UP TO PENNY SIZE AND BRIEF GUSTY
WINDS TO 40 MPH. ALSO FIRE STARTS ARE POSSIBLE WHERE LIGHTNING
STRIKES OUTSIDE THE RAIN CORE.
LAT...LON 3276 11704 3301 11648 3261 11621 3260 11622
3256 11676
TIME...MOT...LOC 1924Z 163DEG 13KT 3240 11627
PURPURAThe Santa Ana Mts radar (KSOX), 49 km away, was scanning. The volume nearest the first event began at 20:58 UTC.
2 heavy rain, 1 flash flood. Local standard time, as filed.
Heavy rain from a short-lived, intense thunderstorm caused frequent lightning, gusty winds, which downed a few trees, and dumped enough rain to cause minor street flooding. Smoke was also seen from spot fires started by lightning in the mountains near Murrieta.
Around 1855 PDT, local law enforcement reported flooding on Shadow Mountain Road west of Highway 395 and on Highway 395 itself. Estimates of up to two feet of water on the flooded roadways was reported due to very heavy rainfall in the El Mirage, Phelan and Adelanto areas, north of Victorville.
A short, but intense thunderstorm near Borrego Springs caused runoff from heavy rain to enter some stores in town as well as a roof torn off due to gusty winds.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2010Every state in 2010This day in weather historyWarnings in California, July 2010
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: 250198, 251930, 251900.