A Pacific cold front helped lift deep subtropical moisture seeping north from the remnants of Hurricane Jimena, triggering severe storms and flash flooding in the Mojave Desert.
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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 VEF wrote it up.
A Pacific cold front helped lift deep subtropical moisture seeping north from the remnants of Hurricane Jimena, triggering severe storms and flash flooding in the Mojave Desert.
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 Las Vegas, NV wrote its last area forecast discussion before the first event at Sep 4, 9:05 AM PST, 2 hours 1 minute earlier.
AREA FORECAST DISCUSSION UPDATE NATIONAL WEATHER SERVICE LAS VEGAS NV 1005 AM PDT FRI SEP 4 2009 .SYNOPSIS...A WEATHER DISTURBANCE WILL SLOWLY MOVE FROM THE CENTRAL CALIFORNIA COAST INTO THE SOUTHERN GREAT BASIN TODAY AND TONIGHT. THIS WILL COMBINE WITH MOIST AND UNSTABLE AIR TO PRODUCE ISOLATED TO SCATTERED THUNDERSTORMS ACROSS MUCH OF THE REGION THIS AFTERNOON AND EVENING. DRIER AIR WILL BEGIN TO SPREAD ACROSS THE AREA SATURDAY AND SUNDAY LEADING TO DECREASING THUNDERSTORM COVERAGE ALONG WITH A SLIGHT COOLING TREND. && .UPDATE...12Z MODELS SEEM TO HAVE A BETTER HANDLE ON THE SHORTWAVE PROGGED TO PASS OVER THE AREA TODAY AND TONIGHT...BUT THINK THEY STILL COME UP A LITTLE SHORT ON HOW MUCH DYNAMIC SUPPORT THEY WILL ADD TO THE MIX OVER THE NEXT 18 HOURS. WITH SUFFICIENT MOISTURE IN PLACE AND CLEAR SKIES AT MOST LOCATIONS...EXPECT TO SEE THUNDERSTORM DEVELOPMENT BY NOON OVER HIGHER TERRAIN JUST FROM THERMODYNAMICS. BY THIS AFTERNOON...EXPECT TO SEE SOME ENHANCEMENT/ORGANIZATION AS THE SHORTWAVE MOVES OVER AND INCREASES DYNAMICS. BUFFER SOUNDINGS ARE SHOWING AN INCREASE IN BOTH DIRECTIONAL AND SPEED SHEAR OVER THE COURSE OF THE AFTERNOON...WITH LOW LEVEL WINDS GENERALLY FROM THE SOUTH TAPPING HIGHER PW AIR THEN VEERING WITH HEIGHT FROM THE WEST. THE CURRENT AFTERNOON/EARLY EVENING FORECAST WAS PRETTY MUCH ON TRACK...BUT DID SIGNIFICANTLY BUMP UP POPS OVERNIGHT...ESPECIALLY ACROSS THE EASTERN HALF OF THE FORECAST AREA...AS THE SHORTWAVE KEEPS CONVECTION GOING THROUGH THE NIGHT. && .PREV DISCUSSION...FROM 405 AM PDT. THE MAIN FEATURE TO WATCH TODAY IS THE WEAK SHORTWAVE TROUGH CURRENTLY OFF THE CENTRAL CALIFORNIA COAST. THIS COULD BE CLEARLY SEEN ON WATER VAPOR IMAGERY AND IS FORECAST TO MOVE OVER THE SOUTHERN SIERRA BY THIS AFTERNOON THEN MAKE ITS WAY ACROSS THE SOUTHERN GREAT BASIN TONIGHT. DYNAMIC LIFT AND SLIGHT COOLING SHOULD COMBINE WITH MODERATELY MOIST AND UNSTABLE AIR ALREADY IN PLACE TO ENHANCE CONVECTIVE DEVELOPMENT TODAY. ALSO...FORECAST SOUNDINGS SHOW INCREASING VERTICAL WIND SHEAR WILL DEVELOP THIS AFTERNOON AS THE BASE OF THE TROUGH MOVES IN. THIS SHOULD HELP ORGANIZE AND SUSTAIN SOME THUNDERSTORMS THIS AFTERNOON AND EVENING. ALSO...ISOLATED STORMS MAY CONTINUE THROUGH THE NIGHT ACROSS LINCOLN AND MOHAVE COUNTIES. DRIER AIR IS FORECAST TO MOVE IN BEHIND THIS UPPER LOW SATURDAY WHICH WILL KEEP THUNDERSTORMS CONFINED TO SOUTHEAST NEVADA AND NORTHWEST ARIZONA. FURTHER DRYING OCCURS SUNDAY AS DRY WESTERLY FLOW CONTINUES TO SPREAD OVER THE REGION. ENOUGH MOISTURE AND INSTABILITY MAY LINGER OVER EASTERN MOHAVE COUNTY SUNDAY AFTERNOON TO JUSTIFY A MENTION OF THUNDERSTORMS. THIS PATTERN WILL BRING INCREASING AFTERNOON WINDS...ESPECIALLY BY SUNDAY. HIGH TEMPERATURES WILL LOWER 2-3 DEGREES EACH DAY OVER THE WEEKEND. .LONG TERM...MONDAY THROUGH THURSDAY...STARTS OUT WITH BROAD AND SHALLOW TROUGH OVER THE REGION. FLOW WILL BE WEAK WESTERLY THAT WILL HELP DRY OUT THE WESTERN PART OF THE FORECAST AREA BUT MOISTURE IS PROGGED TO REMAIN OVER THE EAST PART. BY WEDNESDAY THE TROUGH WILL BE WELL PAST AND IN THE NORTHERN PLAINS WITH VERY BROAD RIDGING BUILDING BACK IN FROM THE EAST. HAVE KEPT THE AFTERNOON CONVECTION IN MOHAVE AND LINCOLN COUNTIES WHICH WILL LIKELY BE RECYCLED IN A DIURNAL PATTERN. OF CONCERN IS THE MODELS KEEPING GREATER MOISTURE CONTENT SUPPRESSED JUST TO THE SOUTH OF THE AREA THAT COULD BRING MORE CHANCES OF POPS IN THE EXTENDED TO THE REST OF THE AREA IF THE FLOW SHIFTS TO MORE SOUTHEASTERLY. FOR NOW HAVE KEPT THE DRY FORECAST FOR THE WESTERN PART OF THE AREA. TEMPERATURES WILL BE NEAR NORMAL LEVELS. && .AVIATION...FOR MCCARRAN...PRETTY MUCH A REPEAT OF YESTERDAYS CONDITIONS. FEW TO SCT CLOUDS IN THE MORNING WITH AFTERNOON AND EVENING THUNDERSTORMS TO DEVELOP PRIMARILY OVER LOCAL MOUNTAINS WITH A CHANCE OF A STORM IN THE VALLEY....BUT THAT IS A LOW PROBABILITY. WINDS WILL BE LIGHT AND VARIABLE TODAY WITH THE OUTFLOWS FROM NEARBY THUNDERSTORMS BEING THE MAIN WIND FORECAST PROBLEM. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...TODAY STARTS OUT WITH LITTLE CLOUD COVER THE AREA AND LIGHT WINDS. AFTERNOON AND EVENING THUNDERSTORMS WILL FORM AGAIN TODAY BEGINNING MAINLY OVER MOUNTAIN AREAS BEFORE MOVING INTO VALLEYS. OUTSIDE OF THUNDERSTORM OUTFLOWS WINDS WILL BE GENERALLY LIGHT. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...NONE. AZ...NONE. CA...NONE. && ADAIR/JACQUES HTTP://WEATHER.GOV/LASVEGAS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LAS VEGAS NV 630 AM PDT FRI SEP 4 2009 AZZ001>003-036-CAZ519>527-NVZ014>022-050700- NORTHWEST PLATEAU-LOWER COLORADO RIVER VALLEY-NORTHWEST DESERTS- LAKE MEAD NATIONAL RECREATION AREA-EASTERN SIERRA SLOPES- OWENS VALLEY-WHITE MOUNTAINS OF INYO COUNTY- DEATH VALLEY NATIONAL PARK-WESTERN MOJAVE DESERT- EASTERN MOJAVE DESERT-MORONGO BASIN-CADIZ BASIN- SAN BERNARDINO COUNTY-UPPER COLORADO RIVER VALLEY- ESMERALDA AND CENTRAL NYE COUNTY-LINCOLN COUNTY- NORTHEAST CLARK COUNTY-WESTERN CLARK AND SOUTHERN NYE COUNTY- SHEEP RANGE-SPRING MOUNTAINS-LAS VEGAS VALLEY- SOUTHERN CLARK COUNTY- 630 AM PDT FRI SEP 4 2009 /630 AM MST FRI SEP 4 2009/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST ARIZONA...SOUTHEAST CALIFORNIA AND SOUTHERN NEVADA. .DAY ONE...TODAY AND TONIGHT ISOLATED TO SCATTERED THUNDERSTORMS WILL DEVELOP OVER MUCH OF THE AREA TODAY. ISOLATED HAZARDS SUCH AS SEVERE THUNDERSTORM WIND GUSTS OR FLASH FLOODING WILL BE POSSIBLE WITH SOME STORMS THIS AFTERNOON AND EVENING. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY DRIER AIR MOVING IN FROM THE WEST SATURDAY AND SUNDAY WILL DECREASE THUNDERSTORM COVERAGE SIGNIFICANTLY DURING THE LABOR DAY WEEKEND. ISOLATED THUNDERSTORMS WILL MAINLY BE CONFINED TO NORTHWEST ARIZONA BEYOND SUNDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED TODAY. HOWEVER...SPOTTERS ARE ENCOURAGE TO REPORT SIGNIFICANT WEATHER ACCORDING TO STANDARD OPERATING PROCEDURES. JA
The Las Vegas radar (KESX), 63 km away, was scanning. The volume nearest the first event began at 19:03 UTC.
5 flash flood, 1 hail. Local standard time, as filed.
Heavy rain washed debris onto I-15 between Bailey Rd. and Nipton Rd. The Highway Patrol had to escort vehicles through.
Water and debris flowed across Nipton Rd. at the Nipton Trading Post.
Extensive flooding occurred on Cedar Canyon Road near Lanfair Road.
Ivanpah Rd. was washed out south of New York Mountain Rd.
U.S. Highway 95 was closed from Interstate 40 to mile marker 60 due to flooding. At least one vehicle was stuck.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in California in 2009Every state in 2009This day in weather historyWarnings in California, September 2009
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: 192027, 192030, 192031, 192032, 192033, 192034.