An unseasonably cold early season storm moved south from western Canada, bringing significant weather to sections of Southern California between the 20th and 22nd. Most areas received between one quarter and one inch of rainfall with locally higher amounts associated with thunderstorms.
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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.
An unseasonably cold early season storm moved south from western Canada, bringing significant weather to sections of Southern California between the 20th and 22nd. Most areas received between one quarter and one inch of rainfall with locally higher amounts associated with thunderstorms. In fact, some thunderstorms produced rainfall rates up to 0.70 inches in 20 minutes. With such intense showers, numerous reports of flash flood and debris flows were received in and around recent burn areas. In addition, some gusty thunderstorms winds knocked down power poles across sections of Los Angeles county.
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 Sep 21, 8:00 PM PST, 50 minutes earlier.
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 900 PM PDT FRI SEP 21 2007 .SHORT TERM (TONIGHT THROUGH MONDAY)... ALL EYES ON UPPER LOW CURRENTLY SPINNING AND WOBBLING NEAR 33/122. THERE IS ONE MAIN CONVECTIVE BAND WRAPPED AROUND THE LOW EXTENDING SOUTH OF CATALINA ISLAND AND THEN TURNING INTO MALIBU AND THROUGH EASTERN VENTURA COUNTY. THIS LINE IS GROWING MORE CONVECTIVE WITH TIME AND COULD WELL CREATE ENOUGH RAINFALL TO CAUSE FLASH FLOODING IN GRIFFITH PARK AND THE SHEKELL BURN AREAS. ALSO CONVECTION IS BEGINNING TO INCREASE AROUND THE CORE OF THE LOW WHICH WILL THREATEN MARINE INTERESTS OVERNIGHT. THE 00Z WRF INITIALIZED QUITE WELL (ALTHOUGH WITH THIS STORM GOOD INITIALIZATION HAS NOT TRANSLATED INTO QUALITY FORECASTS) STILL SATELLITE DOES SHOW THE LOW BEGINNING TO NUDGE TO THE NNE WHICH IS ALSO IN LINE WITH THE WRF SOLN AS WELL AS THE 18Z GFS RUN AND THINK THIS IS GOOD ENOUGH TO HAVE MODERATE CONFIDENCE IN THE MDLS. SO...PER THE WRF...EXPECT THE UPPER LOW TO MOVE TO THE NNE OVERNIGHT. REACHING POINT CONCEPTION AT 12Z AND THE EASTERN SLO/MRY COUNTY LINE AT 18Z. THIS WILL SHIFT THE RAIN BAND TO THE NORTH AND OUT OF THE AREA A LITTLE AFTER 12Z. THIS WILL ALLOW THE FOCUS OF THE ACTIVITY TO SHIFT TO THE CORE OF THE LOW ITSELF WHICH WILL BE ALONG THE CENTRAL COAST. THERE WILL BE SOME ENERGY WRAPPING AROUND THE LOW AND OVER VTA AND LA COUNTIES SO A CHANCE OF SHOWERS WILL CONTINUE THERE. WITH ALL THE MOISTURE AND INSTABILITY MOST AREAS WILL BE UNDER MOSTLY CLOUDY SKIES. THE CLOUDS SHOULD DIMINISH OVERNIGHT AS THE SUN SETS AND THE LOW MOVES AWAY. RAINFALL WILL BE LIGHT IN AREAS AWAY FROM THE MAIN RAINBAND...AREAS AFFECTED BY THUNDERSTORMS ALSO WILL HAVE SIGNIFICANTLY MORE RAINFALL. WITH THE CONVECTIVE NATURE OF THE RAINBAND AND THE FACT THAT IT WILL BE TRAINING OVER AN AREA FOR A FEW MORE HOURS EXPECT UP TO AN INCH OF RAIN WITH AN OUTSIDE CHANCE OF UP TO 2 INCHES. AGAIN THESE RAINFALL AMOUNTS WILL AFFECT THE SANTA MONICA MOUNTAIN AREA THE FAR WESTERN VLYS OF L.A. COUNTY...THE EASTERN VALLEYS OF VENTURA COUNTY AND THE MOUNTAINS OF VENTURA COUNTY. LESS ROBUST BUT STILL WORRISOME RAIN BANDS ARE FORMING TO THE SIDES OF THE MAIN RAINBAND AND THESE WILL PUSH INTO CENTRAL L.A. COUNTY AND WESTERN VTA COUNTY OVERNIGHT WITH A HALF INCH POSSIBLE. BY LATE SATURDAY AFTERNOON NW FLOW SHOULD PREVAIL OVER THE AREA AND THIS SHOULD ALLOW SKIES TO CLEAR AND ELIMINATE THE THREAT OF SHOWERS. ...FROM PREVIOUS DISCUSSION... FOR SUNDAY AND MONDAY...EXPECT DRY AND WARMING CONDITIONS FOR ALL AREAS IN THE WAKE OF THE UPPER LOW. BY MONDAY MORNING...SOME WEAK OFFSHORE GRADIENTS ARE FORECASTED TO DEVELOP. SO...THESE OFFSHORE GRADIENTS SHOULD TEMPS TO WARM UP NICELY. AT THIS TIME THE UPPER SUPPORT IS NOT GREAT...SO WILL ONLY EXPECT SOME WEAK AND LOCALIZED CANYON WINDS. .LONG TERM (TUESDAY THROUGH FRIDAY)... ON TUESDAY/WEDNESDAY...THE WEAK OFFSHORE FLOW IN THE MORNINGS IS FORECAST TO REMAIN. SO...WILL EXPECT CONTINUED WARM TEMPS WITH SOME LOCAL CANYON WINDS. FOR THURSDAY/FRIDAY...EXPECT SLIGHTLY COOLER CONDITIONS AS THE WEAK OFFSHORE FLOW ENDS. HOWEVER...DRY CONDITIONS WILL STILL PREVAIL. && .AVIATION... 21/2358Z BANDED PRECIPITATION PRECIPITATION IS STRETCHING FROM KLGB NORTHWEST TO POINT CONCEPTION AND PUSHING TOWARDS THE NORTHWEST. ONE TO THREE HOURS OF PRECIPITATION SHOULD BE EXPECTED AT MOST TERMINALS IN THE LOS ANGELES...VENTURA...AND SANTA BARBARA COUNTIES. PRECIPITATION SHOULD TAPER BY 06Z WITH ANOTHER BAND OF PRECIPITATION POSSIBLE START AT THE COASTAL SITES BY 09Z. IFR TO MVFR CEILINGS AND VISIBILITIES SHOULD BE EXPECTED IN RAIN. A 20 PERCENT CHANCE OF A THUNDERSTORM IS POSSIBLE THROUGH 04Z THIS EVENING IN RAIN SHOWERS. KLAX...IFR TO MVFR CEILINGS AND VISIBILITIES IN RAIN WILL DEVELOP WITHIN THE NEXT 15 MINUTES OR SO. IFR TO MVFR CONDITIONS WILL PERSIST OVER THE NEXT TWO HOURS OR SO...WITH CONDITIONS IMPROVING BETWEEN 0330Z AND 0430Z. A SLIGHT CHANCE OF THUNDERSTORMS WITH VARIABLE AND GUSTY WINDS ARE POSSIBLE THIS EVENING. ANOTHER CHANCE OF IFR TO MVFR CEILINGS AND VISIBILITIES IN RAIN IS POSSIBLE AFTER 09Z. IF IFR TO MVFR DEVELOP...CONDITIONS SHOULD IMPROVE AFTER 16Z. KBUR...IFR TO MVFR CEILINGS AND VISIBILITIES IN RAIN WILL DEVELOP WITHIN THE BETWEEN AROUND 0115Z...PLUS OR MINUS 20 MINUTES. IFR TO MVFR CONDITIONS WILL PERSIST THROUGH 0430Z...TO 0600Z AT THE LATEST. A SLIGHT CHANCE OF THUNDERSTORMS WITH VARIABLE AND GUSTY WINDS ARE POSSIBLE THIS EVENING. ANOTHER CHANCE OF IFR TO MVFR CEILINGS AND VISIBILITIES IN RAIN IS POSSIBLE AFTER 10Z. IF IFR TO MVFR DEVELOP...CONDITIONS SHOULD IMPROVE AFTER 17Z. .LOX WATCHES/WARNINGS/ADVISORIES... FLOOD WATCH (SEE LAXFFALOX). SMALL CRAFT ADVISORY (SEE LAXCWFLOX). MARINE WEATHER STATEMENT (SEE LAXMWSLOX). && PUBLIC...ASR/THOMPSON AVIATION...HALL WWW.WEATHER.GOV/LOSANGELES
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
The Santa Ana Mts radar (KSOX), 85 km away, was scanning. The volume nearest the first event began at 04:50 UTC.
4 flash flood, 1 thunderstorm wind. Local standard time, as filed.
Strong thunderstorms dumped heavy rain over the Island burn area on Santa Catalina Island. The heavy rain produced flash flooding in Avalon Canyon with a school house and a horse stable flooded out. The mud and debris flow prompted the evacuation of Avalon Canyon and Quail Canyon.
California Highway Patrol reported significant flooding at the intersection of Highway 101 and Los Feliz Boulevard.
A severe thunderstorm knocked down seven power poles near Hollywood.
California Highway Patrol reported flash flooding near the community of Gardena along the 110 Freeway north of Highway 91. Numerous vehicles were stuck in several feet of water.
Strong thunderstorms dumped heavy rain over the Barham burn area. The heavy generated a significant mud and debris flow below the burn area. Nearly two feet of mud covered a hundred yard stretch of Forest Lawn Drive. A dozen parked cars were buried by the mud and debris. No injuries were reported.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2007Every state in 2007This day in weather historyWarnings in California, September 2007
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: 52550, 52551, 52558, 52552, 52557.