A few thunderstorms developed along the leading edge of a dry air mass as it pushed into monsoon moisture. 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 few thunderstorms developed along the leading edge of a dry air mass as it pushed into monsoon moisture. 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 Jul 26, 10:12 AM MST, 3 hours 1 minute earlier.
AREA FORECAST DISCUSSION UPDATE NATIONAL WEATHER SERVICE LAS VEGAS NV 1012 AM PDT TUE JUL 26 2011 .SYNOPSIS...DRIER AIR WILL PUSH IN FROM THE WEST TODAY THROUGH WEDNESDAY. THUNDERSTORM CHANCES WILL MAINLY BE LIMITED TO AREAS EAST OF LAS VEGAS BY THIS AFTERNOON AND TO JUST MOHAVE COUNTY WEDNESDAY. MOISTURE WILL BEGIN TO PUSH BACK IN AS EARLY AS THURSDAY...WITH THUNDERSTORM CHANCES SPREADING AREAWIDE BY SATURDAY. HIGH TEMPERATURES WILL BE NEAR NORMAL THROUGH THE WEEK. && .UPDATE...AN AREA OF WEAK VORTICITY PASSING OVER CLARK AND SOUTHEAST LINCOLN COUNTY IS RESULTING IN SCATTERED SHOWERS. MEANWHILE...LATEST WV IMAGERY INDICATES DRY SOUTHWEST FLOW QUICKLY SPREADING FROM WEST TO EAST ACROSS THE FORECAST REGION...WITH THE LEADING EDGE OF DRIER AIR LOFT JUST OVER EASTERN CLARK AND SOUTH ALONG THE COLORADO RIVER VALLEY. NO MAJOR CHANGES WILL BE NEEDED TO THE CURRENT FORECAST...WITH ANY ACTIVITY DURING THE AFTERNOON STILL EXPECTED TO BE MAINLY OVER MOHAVE COUNTY. -KENNEDY- && .AVIATION...FOR MCCARRAN...SOUTHWEST WINDS AT 8 TO 10 KNOTS WILL ACCOMPANY OCCASIONAL SHOWERS THROUGH EARLY AFTERNOON. SKIES WILL BE BKN TO OVC AT AROUND 14 TO 16KFT WITH SOME LOWERING NEAR SHOWERS. SOME BRIEF ENHANCEMENT/VARIABILITY IN WINDS WILL BE POSSIBLE WITH SHOWERS AROUND BUT GUSTS ARE EXPECTED TO REMAIN BELOW 20KTS. CIGS/VIS ARE NOT EXPECTED TO BE DRAMATICALLY RESTRICTED. SOUTHWEST WIND GUSTS ARE EXPECTED LATER THIS AFTERNOON BUT THE TIMING IS MORE CHALLENGING DUE TO THE EARLY MORNING CLOUD COVER. FOR THE REST OF SOUTHERN NEVADA...NORTHWEST ARIZONA...AND SOUTHEAST CALIFORNIA...BKN TO OVC CLOUD COVER AT 14 TO 16K CAN BE EXPECTED OVER CLARK...LINCOLN...AND MOHAVE COUNTIES TODAY WITH SCATTERED SHOWERS. A WEST TO EAST REDUCTION IN CLOUD COVER IS EXPECTED THIS AFTERNOON. WINDS WILL GENERALLY BE BETWEEN 10 TO 15 KTS WITH GUSTS LIKELY BUILDING IN IN THE AFTERNOON. -GIBBS- && .PREV DISCUSSION... 253 AM PDT TUE JUL 26 2011 .SHORT TERM...QUITE A BIT OF MOISTURE STILL OVER THE EASTERN HALF OF THE FORECAST AREA AND SOME SHOWERS AND THUNDERSTORMS LINGERING OVERNIGHT. THE MOST ACTIVE REGION EARLY THIS MORNING WAS NORTHERN MOHAVE COUNTY DUE TO THE INFLUENCE OF A DISTURBANCE MOVING NORTH/NORTHEAST THROUGH WESTERN ARIZONA. MODELS ACTUALLY DEPICT TWO SEPARATE VORTICES...BOTH OF WHICH WILL MAINLY IMPACT POINTS NORTH AND EAST OF MOHAVE COUNTY TODAY. DRIER AIR WILL CONTINUE TO PUSH EAST INTO THE FORECAST AREA DURING THE DAY PUTTING AN END TO THE SHOWERS OVER MOST OF SOUTHERN NEVADA AND SOUTHEAST CALIFORNIA THIS MORNING. MOHAVE COUNTY AND FAR EASTERN PORTIONS OF LINCOLN...CLARK AND SAN BERNARDINO COUNTY COULD STILL SEE THUNDERSTORMS THIS AFTERNOON AS MOISTURE AND WEAK INSTABILITY LINGER. IF THE GFS VERIFIES HOWEVER...THE DRY AIR WILL PUSH EAST A BIT FASTER...LIMITING ANY THUNDERSTORM CHANCES TO JUST EASTERN MOHAVE COUNTY. I WENT WITH THE SLOWER NAM12. WHILE THE DRY AIR DOES MAKE SOME ADDITIONAL EASTWARD PROGRESS TONIGHT AND WEDNESDAY...MODELS NEVER QUITE FLUSH THE MOISTURE OUT OF MOHAVE COUNTY AND I KEPT A SLIGHT CHANCE OF THUNDERSTORMS IN EASTERN MOHAVE COUNTY AND ALONG THE UTAH BORDER IN LINCOLN COUNTY. STRONG HIGH PRESSURE OVER THE FOUR CORNERS COMBINED WITH THE TROUGH WEAKENING OVER THE PACIFIC NORTHWEST AND NORTHERN ROCKIES WILL ALLOW MOISTURE TO PUSH RIGHT BACK IN BY THURSDAY NOW...FASTER THAN EARLIER THOUGHT SO THERE WILL BE A CHANCE OF THUNDERSTORMS ACROSS MUCH OF MOHAVE COUNTY AND UP ACROSS EASTERN CLARK AND MOST OF LINCOLN COUNTY. .LONG TERM...FRIDAY THROUGH MONDAY...NOT MUCH CHANGE IN THE GRIDS AS THE FLOW LOOKS TO REMAIN SOUTHEAST THROUGH MUCH OF THE PERIOD. THIS SHOULD CONTINUE TO DRAW MOISTURE INTO THE AREA THROUGH THE WEEK AND BRING A CHANCE OF THUNDERSTORMS TO THE AREA EACH AFTERNOON. GFS IS SHOWING A COUPLE OF EASTERLY WAVES APPROACHING THE AREA DURING THE EXTENDED PERIOD AND COULD HELP ENHANCE THUNDERSTORM COVERAGE... ESPECIALLY TO THE WEST...BUT THESE SEEM TO BE WEAK AND AM NOT PUTTING MUCH FAITH IN THESE ACTUALLY DEVELOPING AS OF YET. BOTH THE ECMWF AND GFS ARE SHOWING A DRYING TREND LATE IN THE PERIOD AS A WEAK TROUGH APPROACHES THE WEST. ONCE AGAIN THIS COULD DRIVE MONSOONAL MOISTURE EAST...BUT WILL LEAVE A CHANCE OF THUNDERSTORMS IN FOR THE FAR EASTERN AREAS. TEMPERATURES LOOK TO REMAIN CLOSE TO NORMAL...BUT IF THE DRIER AIR MOVES IN LATE IN THE PERIOD WE COULD SEE TEMPERATURES SEVERAL DEGREES ABOVE NORMAL. && .VEF WATCHES/WARNINGS/ADVISORIES... NV...NONE. AZ...NONE. CA...NONE. && HARRISON/GORELOW HTTP://WEATHER.GOV/LASVEGAS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE LAS VEGAS NV 409 AM PDT TUE JUL 26 2011 AZZ001>003-036-CAZ519>527-NVZ014>022-270700- 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- 409 AM PDT TUE JUL 26 2011 /409 AM MST TUE JUL 26 2011/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTHWEST ARIZONA...CALIFORNIA AND SOUTHERN NEVADA. .DAY ONE...TODAY AND TONIGHT DRY AIR WILL CONTINUE TO PUSH IN FROM THE WEST BUT ENOUGH MOISTURE AND INSTABILITY WILL LINGER TO PRODUCE A CHANCE OF THUNDERSTORMS IN AREAS GENERALLY EAST OF LAS VEGAS. BRIEF HEAVY RAIN AND GUSTY WINDS WILL BE POSSIBLE WITH THE STORMS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY THUNDERSTORMS CHANCES WILL BE LIMITED TO MAINLY EASTERN MOHAVE COUNTY ON WEDNESDAY AS DRY AIR PUSHES A LITTLE FARTHER EAST. THIS PUSH OF DRY AIR WILL BE SHORT LIVED HOWEVER. HIGH PRESSURE STRENGTHENING OVER THE FOUR CORNERS WILL START TO PUSH MOISTURE BACK INTO THE AREA FROM THE SOUTHEAST THURSDAY AND MOST AREAS WILL SEE A CHANCE OF THUNDERSTORMS SATURDAY THROUGH MONDAY. .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.
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1217 PM PDT TUE JUL 26 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1213 PM HEAVY RAIN COLORADO CITY 36.99N 112.98W
07/26/2011 E0.00 INCH MOHAVE AZ LAW ENFORCEMENT
LAW ENFORCEMENT REPORTS STREET FLOODING IN COLORADO CITY
AND SEVERAL BASEMENTS THAT HAVE FLOODED. WATER IS
GENERALLY RECEEDING AT THIS TIME.
&&
JGGThe Cedar City radar (KICX), 68 km away, was scanning. The volume nearest the first event began at 20:13 UTC.
1 flash flood. Local standard time, as filed.
Water flowed out of the mountains northeast of Colorado City, closing several roads and also getting into the basements of several homes.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2011Every state in 2011This day in weather historyWarnings in Arizona, July 2011
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: 316397.