Monsoon moisture and some instability from an easterly wave resulted in scattered thunderstorms over the mountains and lower deserts. Most notable of these was a severe thunderstorm that occurred near Mecca in the southern Coachella Valley during the evening.
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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.
Monsoon moisture and some instability from an easterly wave resulted in scattered thunderstorms over the mountains and lower deserts. Most notable of these was a severe thunderstorm that occurred near Mecca in the southern Coachella Valley during the evening. This storm produced a copious amount of lightning and very strong, damaging winds (over 100 power poles damaged or destroyed). While the precipitation did not hit many gages, the Kent Sea Farms gage, near Mecca, recorded 0.32 inches of rain with this storm. After storm damage surveys, it was concluded that the most likely cause of the damage was a brief, nearly-stationary, EF1 tornado.
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 6, 1:00 PM PST, 5 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE SAN DIEGO CA 200 PM PDT THU AUG 6 2015 .SYNOPSIS... MONSOON MOISTURE AND SOME INSTABILITY WILL CONTINUE TO BRING ISOLATED SHOWERS AND THUNDERSTORMS THIS AFTERNOON. ANY RAINFALL THAT OCCURS WILL BE LIGHT. A TROUGH OF LOW PRESSURE WILL MOVE OUT THE MONSOON MOISTURE AND BRING COOLER WEATHER FRIDAY AND SATURDAY. IT WILL ALSO BRING BACK MORE COASTAL CLOUDS NIGHTS AND MORNINGS. FAIR AND SEASONAL SUMMER WEATHER WILL CONTINUE NEXT WEEK. && .DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE... SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO COUNTIES... ISOLATED SHOWERS AND THUNDERSTORMS HAVE BEEN MOVING NORTHWARD MAINLY THROUGH A CORRIDOR OFF THE COAST...INTO ORANGE COUNTY...THE NORTHWEST INLAND EMPIRE...AND NORTH ALONG THE SAN BERN - LA COUNTY LINE INTO THE DESERT. ONLY A COUPLE PLACES HAVE ACTUALLY MEASURED RAINFALL...WITH ADELANTO TOPS AT 0.09 INCH. THERE HAVE BEEN A FEW TSTORMS ELSEWHERE...BUT ISOLATED WITH NO MEASURABLE REPORTS YET. ISOLATED DRY LIGHTNING IN THE MOUNTAINS IS A CONCERN...BUT WILL NOT BE WIDESPREAD. THE PRECIP WILL DIMINISH AFTER SUNSET...IF NOT BEFORE THEN...AS MOISTURE DECREASES FROM SOUTHWEST TO NORTHEAST. A LOW PRESSURE TROUGH OFF THE CALIFORNIA COAST WILL PUSH EAST ACROSS THE STATE TONIGHT INTO FRIDAY. THIS WILL PUSH ASIDE THE MONSOON MOISTURE FOR QUICK DRYING OF THE ATMOSPHERE. IT WILL ALSO DEEPEN UP OUR MARINE LAYER TO PRODUCE MORE EXTENSE COASTAL CLOUDS...PROBABLY ENOUGH TO SNEAK INTO PARTS OF THE INLAND EMPIRE BY SUNRISE FRIDAY. A SIMILAR DEPTH AND EXTENT TO COASTAL CLOUDS ARE EXPECTED SATURDAY. COOLER WEATHER WILL COME TO THE ENTIRE REGION FRIDAY AND SATURDAY WITH TEMPS CLOSE TO SEASONAL AVERAGE. SOME HIGH PRESSURE TRIES TO REBUILD NEXT WEEK SO SLIGHTLY WARMER WEATHER IS EXPECTED...BUT A NEW LOW PRESSURE TROUGH OFF THE COAST WILL DAMPEN THAT TREND. SOUTHERN CALIFORNIA WILL REMAIN IN BETWEEN THE WESTERN TROUGH AND THE EASTERN RIDGE WITH SOME SEASONAL WEATHER. SOME GUIDANCE SHOWS A FAVORABLE POSITION OF THE HIGH PRESSURE RIDGE THAT WOULD BRING IN SOME MONSOON MOISTURE AGAIN NEXT WEDNESDAY OR THURSDAY AND SMALL CHANCES OF THUNDERSTORMS IN THE MOUNTAINS. && .AVIATION... 062030Z...COAST/VALLEYS... A WEAK DISTURBANCE IS MOVING ACROSS THE REGION NOW AND CREATING A FEW THUNDERSTORMS. THEY WILL CONTINUE THIS AFTERNOON...BUT VERY SCATTERED ACROSS THE AREA. LOW CLOUDS...WITH SLIGHTLY HIGHER TOPS AND BASES THAN LAST NIGHT WILL REDEVELOP ALONG THE COAST AND COASTAL VALLEYS THIS EVENING... BUT BREAK OUT ON FRIDAY 0716-1900Z. CONFIDENCE IN STRATUS HEIGHTS AND TIMING IS MODERATE TO HIGH. MTNS/DESERTS...SCT-BKN 10K FT MSL AND A SLIGHT CHC OF -TSRA THROUGH THIS EVENING OTHERWISE UNRESTRICTED VIS AND VFR. FRIDAY OUTLOOK IS A FEW HIGH CLOUDS AOA 10000 FT MSL AND UNRESTRICTED VIS. FORECAST CONFIDENCE HIGH. && .MARINE... 130 PM...A DISTURBANCE MOVING ACROSS THE AREA WILL CREATE A SLIGHT CHANCE OF THUNDERSTORMS UNTIL JUST AFTER SUNSET. GUSTY WINDS...CLOUD TO WATER LIGHTNING...BRIEF HEAVY RAIN AND CHOPPY SEAS MAY DEVELOP NEAR STORMS. OTHERWISE...NO OTHER HAZARDOUS MARINE WEATHER IS EXPECTED FRIDAY THROUGH MONDAY. FORECAST CONFIDENCE MODERATE TO HIGH. && .BEACHES... 130 PM...A DISTURBANCE MOVING ACROSS THE AREA WILL CREATE A SLIGHT CHANCE OF THUNDERSTORMS TODAY. GUSTY WINDS...CLOUD TO WATER/GROUND LIGHTNING AND BRIEF HEAVY RAIN MAY DEVELOP NEAR STORMS. CONDITIONS WILL IMPROVE BY THIS EVENING. && .SKYWARN... SKYWARN ACTIVATION IS NOT REQUESTED. HOWEVER WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS. && .SGX WATCHES/WARNINGS/ADVISORIES... CA...NONE. PZ...NONE. && PUBLIC...MM AVIATION/MARINE/BEACHES...RP
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SAN DIEGO CA
718 PM PDT THU AUG 6 2015
CAZ062-070315-
SAN DIEGO COUNTY DESERTS CA-
718 PM PDT THU AUG 6 2015
AT 715 PM PDT...DOPPLER RADAR WAS TRACKING A LINE OF STRONG
THUNDERSTORMS ALONG THE SAN DIEGO-IMPERIAL COUNTY BORDER FROM
HIGHWAY 78 NEAR OCOTILLO WELLS NORTH TO HIGHWAY S22. THE STORMS WERE
MOVING NORTHEAST AT 25 MPH. STRONG WIND GUSTS TO 50 MPH WILL BE
POSSIBLE WITH THIS STORM...ALONG WITH HEAVY RAINFALL WHICH COULD
PRODUCE LOCAL FLOODING...AND DANGEROUS LIGHTNING. THE STORMS SHOULD
DISSIPATE SHORTLY AFTER 800 PM.
LOCATIONS IMPACTED INCLUDE... HIGHWAY 78 NEAR OCOTILLO WELLS...AND
HIGHWAY S22 ABOUT 10 MILES EAST OF BORREGO SPRINGS NEAR THE IMPERIAL
COUNTY LINE.
LAT...LON 3308 11609 3307 11610 3304 11610 3306 11622
3340 11612 3339 11609 3320 11608
TIME...MOT...LOC 0215Z 183DEG 42KT 3323 11611
MAXWELLThe San Diego radar (KNKX), 115 km away, was scanning. The volume nearest the first event began at 02:29 UTC.
1 thunderstorm wind, 1 tornado. Local standard time, as filed.
Law enforcement reported two large palm trees fell onto the road at 77th and Harrison, as well as a power pole that fell onto a vehicle near 70th and Pierce Streets.
The damage was west of Highway 111 between 64th and 66th Avenues, paralleling Highway 86 towards the mountains, or approximately 3 1/2 miles. An emergency manager for the Imperial irrigation water district (IID) reported a total of 140 poles damaged, 30 of which were steel.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2015Every state in 2015This day in weather historyThe tornado archive for California, 2015Warnings in California, August 2015
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: 599387, 599391.