A surge of monsoonal moisture from northern Mexico produced strong thunderstorms across Ventura and Los Angeles counties. Heavy rain from the thunderstorms resulted in flash flooding and mud/debris flows across the area.
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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 LOX wrote it up.
A surge of monsoonal moisture from northern Mexico produced strong thunderstorms across Ventura and Los Angeles counties. Heavy rain from the thunderstorms resulted in flash flooding and mud/debris flows across the area.
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 Los Angeles, CA wrote its last area forecast discussion before the first event at Jul 29, 12:38 PM PST, 3 hours 2 minutes earlier.
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 138 PM PDT WED JUL 29 2015 .SYNOPSIS... APPROACHING HIGH PRESSURE WILL ALLOW FOR SOUTHEASTERLY MONSOONAL FLOW ALOFT THROUGH THE SATURDAY. THUNDERSTORM POTENTIAL WILL SPREAD NORTHWARD ACROSS THE AREA THROUGH THURSDAY. THE POSSIBILITY OF THUNDERSTORMS WILL LINGER UNTIL SATURDAY FOR THE INTERIOR. BY MONDAY DRY SOUTHWEST WINDS WILL LIKELY REMOVE THE THUNDERSTORM THREAT. && .SHORT TERM (TODAY-SAT)... SATELLITE AND RADAR IMAGERY THIS AFTERNOON IS SHOWING A FEW THUNDERSTORMS POPPING FROM EASTERN LA COUNTY AND POINTS SOUTH AND EAST. SO FAR JUST ONE CELL THAT DEVELOPED OVER THE EASTERN SAN GABRIELS AND MOVED NORTHWESTWARD ACROSS THE EASTERN ANTELOPE VALLEY...PRODUCING A COUPLE OF LIGHTNING STRIKES. STORMS SEEM TO BE MOVING FAIRLY QUICKLY DESPITE MODELS SHOWING WEAK SE STEERING WINDS...SO LIKELY WILL NOT HAVE ANY FLASH FLOOD ISSUES TODAY. BASED ON SATELLITE AND RADAR TRENDS...IT LOOKS LIKE ANY THUNDERSTORMS THAT DEVELOP TODAY...WILL STAYED CONFINED TO THE LA MOUNTAINS AND A.V. OVERALL...IT LOOKS LIKE TOMORROW WILL BE THE MOST ACTIVE WITH REGARDS TO THUNDERSTORMS. SLIGHT CHANCE TO CHANCE THREAT OF THUNDERSTORMS WILL SPREAD NORTHWESTWARD ACROSS THE ENTIRE FORECAST AREA TONIGHT THROUGH TOMORROW...REACHING SLO COUNTY BY TOMORROW AFTERNOON. THE BEST CHANCE FOR SHOWERS/T-STORMS FOR THE COASTAL/VALLEY AREAS FROM LA TO SBA COUNTY WILL BE EARLY TOMORROW MORNING THROUGH ABOUT NOON...AS A WEAK SHORT-WAVE MOVES NORTHWESTWARD ACROSS THE AREA. THE MOUNTAINS AND THE A.V. WILL HAVE THE BEST CHANCE OF SHOWERS/T-STORMS...WITH 30-50% POPS TOMORROW AFTERNOON AND EVENING. THE FLASH FLOOD AND DEBRIS FLOW THREAT FOR THE MOUNTAINS AND A.V. LOOKS GREATER TOMORROW WITH PWATS PEAKING AROUND 1.8". HOWEVER...MODELS CONTINUE TO SHOW 15-20 KT SE STEERING WINDS...SO DECIDED TO HOLD OFF ON ANY FLASH FLOOD WATCHES...ALTHOUGH ISOLATED FLASH FLOODING IS POSSIBLE. SHOWER/T-STORM ACTIVITY SHOULD DECREASE TOMORROW NIGHT INTO FRIDAY MORNING...ESPECIALLY FOR THE COAST/VALLEY AREAS. IN FACT...ONLY REAL CHANGE MADE TO THE PREVIOUS FORECAST WAS TO DECREASE POPS FOR THE COASTAL/VALLEY AREAS TOMORROW EVENING AND NIGHT. ON FRIDAY AND SATURDAY ANY THUNDERSTORM ACTIVITY WILL BE CONFINED TO THE MOUNTAINS...INTERIOR VALLEYS...AND DESERT...AS SE FLOW ALOFT SHIFTS TO THE SOUTH ON FRIDAY...THEN THE SW ON SATURDAY...RESULTING A GRADUAL DRYING TREND. ASIDE FROM THE T-STORM THREAT...ONLY OTHER SIGNIFICANT FORECAST UNCERTAINTIES IN THE SHORT-TERM ARE THE COASTAL STRATUS TONIGHT AND THE MAX TEMPS TOMORROW. VISIBLE SATELLITE IMAGERY SHOWS LOW CLOUDS HANGING TOUGH AT MANY BEACHES THIS AFTERNOON...ESPECIALLY FROM VENTURA NORTH. MOST BEACHES SHOULD CLEAR THIS AFTERNOON. THE LOW CLOUD FORECAST TONIGHT WILL BE PROBLEMATIC WITH THE MID-LEVEL MONSOON MOISTURE MOVING IN. BEST CHANCE FOR LOW CLOUDS AND FOG TONIGHT AND TOMORROW MORNING WILL BE ON THE CENTRAL COAST. TOMORROW COULD END UP BEING JUST AS HOT AS TODAY DEPENDING ON HOW MUCH MID AND HIGH CLOUDS THERE AREA. OVERALL...WE ARE FORECASTING SLIGHTLY COOLER CONDITIONS THURSDAY THROUGH SATURDAY AS HEIGHT/THICKNESS VALUES FALL SOMEWHAT...BUT WITH THE ADDED HUMIDITY...IT WON'T FEEL MUCH COOLER. .LONG TERM (SUN-WED)... THE THUNDERSTORM THREAT WILL CONTINUE TO DIMINISH ON SUNDAY AND MONDAY AS DRY SW FLOW ALOFT BECOMES MORE ESTABLISHED...WITH A RIDGE BUILDING OVER THE WESTERN U.S. AND A TROUGH OF LOW PRESSURE OFF THE COAST. ON SUNDAY...A SLIGHT CHANCE OF T-STORMS WILL LINGER OVER THE EASTERN SAN GABRIELS AND EASTERN ANTELOPE VALLEY. BY MONDAY...THUNDERSTORMS ARE NO LONGER MENTIONED IN THE FORECAST. THE BUILDING RIDGE OVER THE INTERIOR WESTERN U.S. WILL RESULT IN A GRADUAL INCREASE IN HEIGHT/THICKNESS VALUES OVER SW CALIFORNIA SUNDAY THROUGH WEDNESDAY...BRINGING SLIGHT WARMER CONDITIONS TO THE REGION. AT THIS POINT...IT JUST LOOKS LIKE SLIGHTLY ABOVE NORMAL TEMPERATURES. && .AVIATION...29/1740Z... MARINE LAYER AROUND 014 THIS MORNING. IFR/MVFR STRATUS SHOULD CLEAR OUT OF ALL AIRPORTS BY 19Z. MODERATE CONFIDENCE OF SIMILAR IFR/LIFR CATS AT KSBP AND KSMX WHEN COMPARED TO YESTERDAY. LOW CONFIDENCE ELSEWHERE AS MID-LEVEL CLOUDS WILL BE MOVING IN FROM THE SOUTH. MODERATE CONFIDENCE THAT THIS MOISTURE WILL BRING THUNDERSTORMS TO MOUNTAINS AND DESERTS THIS AFTERNOON/EVENING AS WELL AS THURSDAY. LOW CONFIDENCE FOR THUNDERSTORMS ELSEWHERE...WITH A 20 PERCENT CHANCE STARTING LATE TONIGHT OVER LOS ANGELES COUNTY...AND STARTING ELSEWHERE ON THURSDAY. KLAX...MODERATE CONFIDENCE IN VFR FROM 19Z TO 24Z TODAY. CIGS NEAR 012 SHOULD BE NEAR COASTLINE...WITH A 30 PERCENT CHANCE OF A CIG ANYTIME TODAY. MID-LEVEL CLOUDS WILL ARRIVE THIS EVENING...BRINGING A 20 PERCENT CHANCE OF A SHOWER OR THUNDERSTORM AFTER 09Z. VERY LOW CONFIDENCE FOR MVFR/IFR CIGS TONIGHT AS MID-LEVEL CLOUDS WILL DISRUPT FORMATION. KBUR...HIGH CONFIDENCE IN VFR FROM 19Z TO 06Z TODAY. THERE IS A 20 PERCENT CHANCE OF A CIGS AFTER 06Z TONIGHT...BUT CONFIDENCE IS VERY LOW AS MID-LEVEL CLOUDS WILL ARRIVE THIS EVENING AND DISRUPT FORMATION. THERE IS A 20 PERCENT CHANCE OF A SHOWER OR THUNDERSTORM AFTER 09Z. && .MARINE...29/900 AM. HIGH CONFIDENCE IN GENERALLY LIGHT WINDS FOR AT LEAST THE NEXT 36 HOURS. FOG WITH SOME VISIBILITIES NEAR 1 MILE WILL CONTINUE THIS MORNING AND MAY FOR AGAIN THURSDAY MORNING...ESPECIALLY NORTH OF POINT CONCEPTION. MODERATE LONG PERIOD SWELL WILL CONTINUE TO IMPACT THE AREA THROUGH THURSDAY. THUNDERSTORMS WILL BE POSSIBLE LATE TONIGHT THROUGH EARLY FRIDAY MORNING. THE BEST CHANCE WILL BE THURSDAY MORNING AS A DISTURBANCE MOVES THROUGH THE AREA FROM THE SOUTH. && .LOX WATCHES/WARNINGS/ADVISORIES... HIGH RIP CURRENT RISK (SEE LAXSRFLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX). SPECIAL WEATHER STATEMENT (SEE LAXSPSLOX). && PUBLIC...SUKUP AVIATION/MARINE...KITTELL SYNOPSIS...RM WWW.WEATHER.GOV/LOSANGELES
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 1209 PM PDT WED JUL 29 2015 CAZ034>041-044>046-051>054-059-087-088-547-548-301300- SAN LUIS OBISPO COUNTY CENTRAL COAST- SANTA BARBARA COUNTY CENTRAL COAST-SANTA YNEZ VALLEY- SAN LUIS OBISPO COUNTY INTERIOR VALLEYS-CUYAMA VALLEY- SANTA BARBARA COUNTY SOUTH COAST-VENTURA COUNTY COAST- LOS ANGELES COUNTY COAST INCLUDING DOWNTOWN LOS ANGELES- VENTURA COUNTY INTERIOR VALLEYS-VENTURA COUNTY COASTAL VALLEYS- SANTA MONICA MOUNTAINS RECREATIONAL AREA- SAN LUIS OBISPO COUNTY MOUNTAINS- SANTA BARBARA COUNTY MOUNTAINS-VENTURA COUNTY MOUNTAINS- LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE- ANTELOPE VALLEY-CATALINA ISLAND-SANTA CLARITA VALLEY- LOS ANGELES COUNTY SAN FERNANDO VALLEY- LOS ANGELES COUNTY SAN GABRIEL VALLEY- 1209 PM PDT WED JUL 29 2015 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA. .DAY ONE... TODAY THERE IS A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON AND TONIGHT IN THE MOUNTAINS OF LOS ANGELES AND VENTURA COUNTIES AND THE ANTELOPE VALLEY...WITH A SLIGHT CHANCE OF THUNDERSTORMS ACROSS ALL OF LOS ANGELES COUNTY BY LATE TONIGHT. ISOLATED FLASH FLOODING IS POSSIBLE. THERE WILL BE A HIGH RISK OF RIP CURRENTS OVER THE LOS ANGELES COUNTY BEACHES TODAY...WITH A MODERATE RISK OVER OTHER BEACHES. * HIGH RIP CURRENT RISK......SEE FZUS56 KLOX - SRFLOX FOR DETAILS * * SPECIAL WEATHER STATEMENT..SEE WWUS86 KLOX - SPSLOX FOR DETAILS * .DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY THERE IS CHANCE OF SHOWERS AND A SLIGHT CHANCE OF THUNDERSTORMS ACROSS MUCH OF THE REGION THURSDAY AND THURSDAY NIGHT. SOME THUNDERSTORMS MAY PRODUCE HEAVY RAIN...ISOLATED FLASH FLOODING POSSIBLE. THERE IS A SLIGHT CHANCE OF THUNDERSTORMS ACROSS INTERIOR SECTIONS OF SAN LUIS OBISPO AND SANTA BARBARA COUNTIES...THE MOUNTAINS OF LOS ANGELES AND VENTURA COUNTIES...AND THE ANTELOPE VALLEY FRIDAY.THERE IS A SLIGHT CHANCE OF THUNDERSTORMS ACROSS THE MOUNTAINS OF LOS ANGELES AND VENTURA COUNTIES...AND THE ANTELOPE VALLEY SATURDAY AND SUNDAY. * SPECIAL WEATHER STATEMENT..SEE WWUS86 KLOX - SPSLOX FOR DETAILS * .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. RK/DB
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE OXNARD CA 318 PM PDT WED JUL 29 2015 CAZ054-059-292315- ANTELOPE VALLEY CA- LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE CA- 318 PM PDT WED JUL 29 2015 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN LOS ANGELES COUNTY UNTIL 415 PM PDT... AT 313 PM PDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR NORTH OF PEARBLOSSOM AND EAST OF PALMDALE AND LANCASTER...MOVING NORTHWEST AT ABOUT 15 MPH. IN ADDITION TO LOCAL FLOODING OF ROADWAYS...HALF INCH HAIL AND WIND GUSTS UP TO 50 MPH WILL BE POSSIBLE WITH THIS STORM. A FLASH FLOOD WARNING OR SEVERE THUNDERSTORM WARNING MAY NEED TO BE ISSUED IF THIS STORM INTENSIFIES. LOCATIONS IMPACTED MAY INCLUDE...LANCASTER...PALMDALE...LAKE LOS ANGELES...PEARBLOSSOM...LAKE PALMDALE...SADDLEBACK BUTTE STATE PARK...AND HIGHWAYS 138 AND 14. LAT...LON 3445 11805 3482 11834 3482 11773 3451 11768 TIME...MOT...LOC 2213Z 240DEG 48KT 3474 11743 SUKUP
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
426 PM PDT WED JUL 29 2015
CAZ054-059-300015-
ANTELOPE VALLEY CA-
LOS ANGELES COUNTY MOUNTAINS EXCLUDING THE SANTA MONICA RANGE CA-
426 PM PDT WED JUL 29 2015
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN LOS ANGELES COUNTY
UNTIL 515 PM PDT...
AT 422 PM PDT...DOPPLER RADAR WAS TRACKING A CLUSTER OF STRONG
AND SLOW MOVING THUNDERSTORMS OVER THE EASTERN PORTION OF THE ANTELOPE
VALLEY AND SAN GABRIEL MOUNTAINS.
IN ADDITION TO FLOODING OF ROADWAYS...HALF INCH HAIL...WIND GUSTS
UP TO 50 MPH...AND FREQUENT LIGHTNING WILL CONTINUE WITH THESE STORMS.
LOCATIONS IMPACTED INCLUDE...
LANCASTER...PALMDALE...LAKE LOS ANGELES...WRIGHTWOOD...PEARBLOSSOM...LLANO...
LITTLEROCK...AND BIG PINES.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.
&&
LAT...LON 3425 11766 3424 11766 3454 11847 3482 11836
3482 11767 3430 11765
TIME...MOT...LOC 2322Z 239DEG 49KT 3466 11769
GOMBERG/SUKUPThe Edwards AFB radar (KEYX), 61 km away, was scanning. The volume nearest the first event began at 23:40 UTC.
6 flash flood. Local standard time, as filed.
Strong thunderstorms producing flash flooding in the community of Lake Los Angeles. At the intersection of 170th Street East and Avenue P8, over eight inches of water flooded the intersection.
Strong thunderstorms formed over north central Los Angeles county, north of the community of Acton. Heavy rain from the thunderstorms generated numerous mud/debris flows across Highway 14 between Red Rover Mine Road and Escondido Canyon Road.
Strong thunderstorms developed in the mountains of Ventura county. Heavy rain from the thunderstorms generated flash flooding near the intersection of Highway 33 and Corral Canyon Road.
Strong thunderstorms developed near Pyramid Lake in Los Angeles county. Heavy rain from the thunderstorms generated flash flooding along Interstate 5 near Vista del Lago Road. Several vehicles were stranded in the flood waters.
Strong thunderstorms developed near the community of Llano. Heavy rain from these thunderstorms produced flash flooding along the intersection of Highway 138 and 165th Street East.
Strong thunderstorms developed near the community of Llano. Heavy rain from these thunderstorms generated flash flooding and mud flows. California Highway Patrol reported 6 to 8 inches of mud across sections of Highway 138.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2015Every state in 2015This day in weather historyWarnings in California, July 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: 596626, 596627, 596632, 596628, 596629, 596634.