From September 1st through the 2nd, monsoonal moisture continued to produce strong thunderstorms across the mountains and deserts. Some thunderstorms reached severe levels, producing wind damage including a weak tornado.
Every event with a place to put it. Tap one for its entry below.
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.
From September 1st through the 2nd, monsoonal moisture continued to produce strong thunderstorms across the mountains and deserts. Some thunderstorms reached severe levels, producing wind damage including a weak tornado. Also, several reports of flash flooding were received.
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 1, 2:26 PM PST, 34 minutes earlier.
SOUTHWEST CALIFORNIA AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA 326 PM PDT SAT SEP 1 2007 .SHORT TERM...(TONIGHT-TUE) EXCESSIVE HEAT WARNING HAS BEEN EXTENDED THROUGH SUNDAY BETWEEN THE HOURS OF 10 AM TO 7 PM BOTH TODAY AND FOR SUNDAY FOR THE MOUNTAINS AND VALLEYS OF LOS ANGELES AND VENTURA COUNTIES. ALSO ADDED THE SAN LUIS OBISPO INTERIOR VALLEYS AS WELL. PASO ROBLES JUST MET GUIDANCE AS TRIPLE DIGIT TEMPS AND DECENT RH VALUES WERE APPARENT AND THEREFORE WAS ADDED THROUGH SUNDAY. TEMPS SHOULD BE SIMILAR TO YESTERDAY IN MANY LOCATIONS. DOWNTOWN LOS ANGELES HAS REACHED 95 AND HAS PROBABLY PEAKED FOR THE AFTERNOON. THE OTHER BIG CONCERN OF THE DAY IS THE RETURN OF CONVECTION ACROSS THE MOUNTAINS OF LOS ANGELES...VENTURA AND POSSIBLY SANTA BARBARA COUNTY MOUNTAINS AND THE ANTELOPE VALLEY. CONVECTIVE PARAMETERS LOOKED GOOD ONCE AGAIN FOR THE LA COUNTY MOUNTAINS AND THE ANTELOPE VALLEY FOR SLOW MOVING TO STATIONARY THUNDERSTORMS TO INITIATE OVER THE LA COUNTY MOUNTAINS AND CONTINUE ACROSS THE ANTELOPE VALLEY ONCE AGAIN TODAY. A FLASH FLOOD WATCH HAS BEEN ISSUED FOR THIS AFTERNOON FOR BOTH LA COUNTY MOUNTAINS AND ANTELOPE VALLEY TODAY. LATEST SATELLITE IMAGERY INDICATES A FEW CELLS DEVELOPING OVER THE SAN GABRIEL RANGE THIS AFTERNOON. EXPECTING A SIMILAR DAY IN REGARDS TO CONVECTION AS YESTERDAY . EXPECTING A FEW ISOLATED SHOWERS AND THUNDERSTORMS FOR THE VENTURA AND SBA COUNTY MOUNTAINS TODAY AS WELL. MONDAY WILL CONTINUE TO BE QUITE HOT AS UPPER LVL HIGH EXPANDS OVER MUCH OF THE INTERMOUNTAIN REGION. HEIGHTS WILL BEGIN TO LOWER SLIGHTLY...AND WITH 950 MB TEMPS DOWN A DEGREE OR TWO...A VERY SLIGHT COOLING TREND WILL BEGIN. HOWEVER...TEMPS WILL REMAIN WELL ABOVE AVERAGE AND THE EXCESSIVE HEAT WARNING MIGHT NEED TO BE EXPANDED FOR LABOR DAY. ANOTHER THREAT OF THUNDERSTORMS SHOULD AFFECT THE SAME AREAS ONCE AGAIN. IN FACT...LATEST WRF/GFS MODELS SHOW DECENT MONSOONAL FRONT...K INDEX AND LIFTED INDEX VALUES BECOMING QUITE IMPRESSIVE ALL ACROSS THE INTERIOR SECTIONS OF THE FORECAST AREA ON MONDAY. POPS IN THE LOCAL MOUNTAINS AND ANTELOPE VALLEY MIGHT HAVE TO BE RAISED TO CHANCE WORDING IF MODELS CONTINUE TO SHOW THIS NEXT INFLUX OF MID LVL MOISTURE STREAMING INTO THE AREA. MID LVL WINDS WILL CONTINUE TO BE FAVORABLE TO KEEP THIS SAME MONSOONAL PATTERN IN PLACE THROUGH TUES. TEMPS WILL CONTINUE TO TREND DOWN ON TUE AS HIGH PRESSURE CONTINUES TO BREAKDOWN AND PUSH FARTHER WEST AND NORTH OVER THE EASTERN PACIFIC. TEMPS WILL STILL BE IN THE LOWER TRIPLE DIGITS IN WARMEST VALLEYS AND ANTELOPE VALLEY. UPPER LVL WINDS WILL BEGIN TO TURN MORE BROADLY SW IN DIRECTION IN THE NORTHERN ZONES...SO SLIGHT CHANCE POPS ONCE AGAIN FOR LA/VTU COUNTY MTNS. .LONG TERM...(WED-SAT) WHAT IS NOW TROPICAL STORM HENRIETTE...AND LIKELY TO BECOME A HURRICANE OVER THE NEXT 24 HOURS WILL MOVE UP THE BAJA PENINSULA THROUGH THE EXTENDED PERIOD. GFS AND ECMWF ARE IN SLIGHT DISAGREEMENT...BUT BOTH AGREE THAT WHAT WILL BE LEFT OVER SHOULD STAY TO THE EAST THROUGH AZ. TEMPS WILL CONTINUE TO TREND COOLER BUT REMAIN ABOVE NORMAL THROUGH THURSDAY. ALTHOUGH REMNANTS FROM WHAT SHOULD BE HURRICANE HENRIETTE SHOULD MOVE EAST OF THE FORECAST AREA...THERE COULD BE ENOUGH MOISTURE IN THE MID LEVELS TO CAUSE A FEW SHOWERS OR THUNDERSTORMS IN THE SOUTHEASTERN SECTIONS OF THE FORECAST AREA. COOLING WILL CONTINUE THROUGH SATURDAY TO MORE NORMAL TEMPS FOR THIS TIME OF YEAR. && .AVIATION...01/1910Z GOOD CONFIDENCE IN ALL LOCATIONS REMAINING CLEAR OVERNIGHT. KPMD AND KWJF MAY STRUGGLE WITH SOME CONVECTION THIS AFTERNOON. KLAX...GOOD CONFIDENCE IN CLEAR SKIES THROUGH SUNDAY WITH NORMAL SEA BREEZES. KBUR...EXCELLENT CONFIDENCE IN CLEAR SKIES THROUGH SUNDAY WITH NORMAL SEA BREEZES. .LOX WATCHES/WARNINGS/ADVISORIES... FLASH FLOOD WARNING (SEE LAXFFWLOX). EXCESSIVE HEAT WARNING (SEE LAXNPWLOX). FLOOD WATCH (SEE LAXFFALOX). SMALL CRAFT ADVISORY (SEE LAXCWFLOX). HIGH RIP CURRENT RISK (SEE LAXSRFLOX). && PUBLIC...KAPLAN AVIATION...SWEET WWW.WEATHER.GOV/LOSANGELES
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
The national radar mosaic for the moment the first event began.
2 flash flood, 1 thunderstorm wind, 1 tornado. Local standard time, as filed.
A trained spotter in the community of Lancaster reported a severe thunderstorm with winds in excess of 60 MPH. The thunderstorm winds knocked down trees and 5-inch diameter branches along the Antelope Valley Freeway between Avenue N and 50th Street East.
A pilot at the Lancaster airport reported a weak tornado on ground to the southeast of the airport. No damage or injuries were reported.
Strong monsoonal thunderstorms produced heavy rain and flash flooding in the community of Palmdale. A trained spotter reported flash flooding near the intersection of Palmdale Boulevard and Avenue J.
Strong monsoonal thunderstorms over the Los Angeles county mountains produced flash flooding between Mountain High ski resort and the community of Wrightwood.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2007Every state in 2007This day in weather historyThe tornado archive for California, 2007Warnings 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: 47291, 47293, 47284, 47288.