A Pacific storm system triggered a few thunderstorms over the Mojave Desert. One storm produced flash flooding.
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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 storm system triggered a few thunderstorms over the Mojave Desert. One storm produced flash flooding.
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 12, 2:30 PM MST, 2 hours earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE LAS VEGAS 230 PM PDT SAT SEP 12 2009 .SYNOPSIS...SOUTHWEST FLOW WILL CONTINUE OVER THE REGION AHEAD OF A PACIFIC LOW PRESSURE SYSTEM CURRENTLY APPROACHING THE WEST COAST. THIS SYSTEM WILL APPROACH THE AREA SUNDAY PRODUCING STRONGER WINDS ALONG WITH CONTINUING THE THREAT FOR MAINLY AFTERNOON AND EVENING THUNDERSTORMS FOR THE SOUTHERN GREAT BASIN AND MOHAVE COUNTY AS WELL AS THE CLARK COUNTY MOUNTAINS. AS THE LOW PRESSURE SYSTEM MOVES THROUGH THE AREA MONDAY AND INTO TUESDAY...MOISTURE WILL BE SWEPT EASTWARD ENDING THE THUNDERSTORM THREAT...BUT CAUSING TEMPERATURES TO COOL TO NEAR OR SLIGHTLY BELOW SEASONAL NORMALS. HIGH TEMPERATURES WILL THEN SLOWLY RISE AFTER WEDNESDAY TOWARD THE WEEKEND. && .SHORT TERM...SATELLITE IMAGERY SHOWING INITIAL DISTURBANCE MOVING OVER THE RENO REGION WITH THE DEFORMATION ZONE SETTING UP FROM NORTHWEST TO SOUTHEAST ACROSS THE FORECAST AREA. ISOLATED TO SCATTERED THUNDERSTORMS ARE FIRING ALONG THE DEFORMATION ZONE IN THE EASTERN PART OF THE FORECAST AREA WHERE MOISTURE IS DEEPEST. ADDITIONAL STORMS ARE FIRING UNDER THE DISTURBANCE ALONG THE SIERRA CREST AS WELL. EXPECT THIS ACTIVITY TO DIE DOWN THIS EVENING AFTER SUNSET WITH CLOUD REMNANTS LINGERING OVERNIGHT. MAIN LOW PRESSURE SYSTEM CONTINUES TO DIVE ALONG THE WEST COAST AND WILL SWING ONSHORE SUNDAY NIGHT AND SWEEP ACROSS THE FORECAST AREA MONDAY INTO TUESDAY. AHEAD OF THE SYSTEM...SOUTHWEST WINDS WILL INCREASE AND BECOME GUSTY SUNDAY INTO MONDAY. WIND GUSTS AND MIN RH VALUES CLOSE TO RED FLAG CRITERIA ACROSS ISOLATED AREAS OF SOUTH CENTRAL NEVADA...BUT AT THIS POINT LOOKS MARGINAL AND WINDS MAY NOT REACH THE REQUIRED DURATION CRITERIA. OTHERWISE...DEEPER MOISTURE WILL REMAIN CONFINED TO EASTERN SECTIONS OF THE FORECAST AREA WITH A CONTINUED THREAT FOR MAINLY AFTERNOON AND EVENING THUNDERSTORMS SUNDAY AND AGAIN ON MONDAY. MODELS CONTINUE TO ADVERTISE SOME ARIZONA MOISTURE MOVING NORTHWEST TOWARD THE LOW WITH AN INCREASE IN MOISTURE VALUES IN LINCOLN AND MOHAVE COUNTIES SUNDAY NIGHT INTO MONDAY BEFORE THE SYSTEM MOVES THROUGH AND DRIER AND STABLE AIR MOVES INTO THE AREA. HAVE KEPT WITH HIGHER POPS IN THIS AREA DURING THIS PERIOD. TEMPERATURES EXPECTED TO COOL MONDAY AND TUESDAY WITH THIS SYSTEM. .LONG TERM...WEDNESDAY MORNING THROUGH SATURDAY...NOT MUCH CHANGE IN OUTLOOK AS MODELS STILL HAVE THE CLOSED LOW CLOSE TO SOUTHERN UTAH TO THE FOUR CORNERS AREA WEDNESDAY MORNING UNDER A STRONG RIDGE. THERE ARE DIFFERENCES AS THE REST OF THE WEEK PROGRESSES ON THE DEVELOPMENT OF A RIDGE TO BUILD IN FROM THE PACIFIC. THEY PRETTY MUCH AGREE ON THE PACIFIC NORTHWEST TROUGH MOVING THROUGH WELL TO THE NORTH ON THURSDAY AND WILL ASSIST IN MOVING THE UTAH/FOUR CORNERS LOW FURTHER EAST. THE GFS IS MORE BULLISH IN THE EXTENT AND STRENGTH OF THE PACIFIC RIDGE BUILDING IN. WENT WITH THIS WAY IN THE FORECAST BUT NOT AS STRONG AS THE GFS. AS A RESULT HAVE RAISED THE TEMPERATURE FORECAST A DEGREE OR TWO OVER THE PREVIOUS FORECAST WHICH WILL KEEP US IN ABOVE NORMAL TEMPERATURES. IF GFS VERIFIES NEXT WEEKEND COULD BE WARMER IF THE FORECAST UPPER HIGH SETS UP OVER NEVADA. ASIDE FROM TEMPERATURES PRETTY MUCH LEFT THE PREVIOUS FORECAST INTACT...MOSTLY DRY AND LITTLE IN THE WAY OF CLOUD COVER. && .AVIATION...FOR MCCARRAN...THUNDERSTORM CHANCES ARE SLIM AT KLAS BUT IT IS NOT OUT OF THE QUESTION FOR OUTFLOW BOUNDARIES FROM NEARBY STORMS TO AFFECT THE VALLEY/KLAS WINDS. OUTSIDE OF OUTFLOWS...WINDS WILL BE LIGHT AND FOLLOW DIURNAL PATTERNS. SUNDAY AFTERNOON WILL SEE STRONGER SOUTH TO SOUTHWEST WINDS AS A SYSTEM APPROACHES FROM THE WEST COAST. FOR NOW THINKING KLAS WILL SEE GUSTS IN THE 25 TO 30 KNOT RANGE. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...THERE IS A SLIGHT CHANCE OF THUNDERSTORMS INTO THIS EVENING AND AGAIN TOMORROW AFTERNOON...MAINLY OVER HIGHER TERRAIN. SURFACE WINDS WILL REMAIN RELATIVELY LIGHT OUTSIDE OF ANY THUNDERSTORMS...FOLLOWING TYPICAL DIURNAL TRENDS. GUSTY SOUTHWEST WINDS ARE EXPECTED SUNDAY AND MONDAY AS A LOW PRESSURE SYSTEM APPROACHES THE AREA FROM THE WEST. -KENNEDY-&& .FIRE WEATHER...SOUTHWEST FLOW WILL INCREASE SUNDAY INTO MONDAY WITH LOCALLY BREEZY CONDITIONS. AT THIS TIME IT LOOKS MARGINAL FOR WIDESPREAD RED FLAG CONDITIONS AS MANY AREAS WILL HAVE MINIMUM RELATIVE HUMIDITY VALUES REMAINING ABOVE 15 PERCENT BUT WIDESPREAD WIND GUSTS OVER 35 MPH MAY NOT REACH THE REQUIRED DURATION CRITERIA. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...NONE. AZ...NONE. CA...NONE. && STAUDENMAIER/JACQUES HTTP://WEATHER.GOV/LASVEGAS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LAS VEGAS NV 511 AM PDT SAT SEP 12 2009 AZZ001>003-036-CAZ519>527-NVZ014>022-130600- 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- 511 AM PDT SAT SEP 12 2009 /511 AM MST SAT SEP 12 2009/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST ARIZONA...CALIFORNIA AND SOUTHERN NEVADA. .DAY ONE...TODAY AND TONIGHT A WEAK DISTURBANCE MOVING THROUGH CENTRAL CALIFORNIA INTO NORTHERN NEVADA WILL COMBINE WITH AN INCREASE IN MID LEVEL MOISTURE TO PRODUCE A SLIGHT CHANCE OF THUNDERSTORMS THIS AFTERNOON AND EVENING OVER THE HIGHER TERRAIN...MAINLY IN THE SIERRA AND MOHAVE COUNTY. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY A STRONGER DISTURBANCE APPROACHING THE AREA WILL BRING INCREASING WINDS SUNDAY WHILE ISOLATED THUNDERSTORMS WILL STILL BE POSSIBLE ACROSS MOHAVE AND EASTERN LINCOLN COUNTY. THIS DISTURBANCE WILL MOVE THROUGH CALIFORNIA INTO NEVADA MONDAY BRINGING A CHANCE OF THUNDERSTORMS TO THE SOUTHERN GREAT BASIN...MOHAVE COUNTY AND THE MOUNTAINS IN CLARK COUNTY. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME. HOWEVER, SPOTTERS ARE ENCOURAGED TO REPORT ANY SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
The Las Vegas radar (KESX), 76 km away, was scanning. The volume nearest the first event began at 23:27 UTC.
1 flash flood. Local standard time, as filed.
Over a foot of flowing water covered the intersection of Pierce Ferry Rd. and Charles Dr.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2009Every state in 2009This day in weather historyWarnings in Arizona, 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: 192035.