Thunderstorms developed across the western portions of the Phoenix area during the evening hours as outflows from earlier storms interacted with each other.
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 PSR wrote it up.
Thunderstorms developed across the western portions of the Phoenix area during the evening hours as outflows from earlier storms interacted with each other.
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 Phoenix, AZ wrote its last area forecast discussion before the first event at Aug 12, 9:40 PM MST, 42 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PHOENIX AZ 940 PM MST WED AUG 12 2009 .SYNOPSIS... STRONG HIGH PRESSURE REMAINS OVER NEW MEXICO...WITH A WEAK LOW MOVING ACROSS NORTHERN MEXICO. THIS PATTERN WILL RESULT IN VARIABLE CLOUDINESS AND AN INCREASING CHANCE OF SHOWERS AND THUNDERSTORMS BY THURSDAY OVER SOUTHWEST AND SOUTH-CENTRAL ARIZONA. HIGH TEMPERATURES ARE EXPECTED TO BE COOLER THURSDAY AND FRIDAY. STORM CHANCES WILL CONTINUE FRIDAY BEFORE A LOW PRESSURE SYSTEM MOVING ACROSS THE WESTERN STATES BRINGS MUCH DRIER AIR THIS WEEKEND WITH TEMPERATURES NEAR NORMAL INTO NEXT WEEK. && .DISCUSSION... NOT MUCH HAPPENING THIS EVENING ACROSS THE PHX CWA ASIDE FROM SOME ISOLD CONVECTIVE ACTIVITY OVER THE SCNTRL PORTIONS. EARLIER STORMS DROPPED SOME FAIRLY DECENT RAINFALL AMOUNTS OVER THE HIGHER TERRAIN N OF GLOBE...WITH RADAR ESTIMATES OF OVER 2 INCHES...LIKELY A BIT OVERDONE...BUT STILL PRETTY DECENT. SMALL STREAM FLOOD ADVY WAS ISSUED TO COVER THIS EVENT. MEANWHILE...00Z SOUNDINGS INDICATE THAT A BIT MORE MOISTURE WAS IN PLACE IN THE BOUNDARY/LOWER LAYERS OF THE ATMOS THAN MODELS ARE INITIALLY GIVING CREDIT FOR. KPSR SOUNDING UP TO OVER AN INCH AND A HALF...WITH MEAN BOUNDARY LAYER MIXING RATIOS...SURFACE-H7...IN THE 9 TO 9.5 INCH RANGE. FOR TOMORROW... SOME WEAK TO MODERATE UPPER LEVEL SPEED DIVERGENCE EXPECTED...ALONG WITH A WEAK IMPULSE FROM THE S COULD AID IN CONVECTIVE DEVELOPMENT. POPS ARE ALREADY ABOVE CLIMO FOR THE DAYTIME PERIOD...MAINLY IN THE CHANCE CATEGORY FOR SCNTRL DESERTS...AND THIS LOOKS GOOD FOR NOW. UPCOMING MID SHIFT MAY WANT TO CONSIDER INCREASING POPS A BIT OVER WHAT IS CURRENTLY OUT FOR THURSDAY EVENING FOR THE SCNTRL DESERTS AS SOME POTENTIAL DYNAMICS BEGINS TO COME INTO PLAY FROM APRCHG W COAST TROUGH. FRIDAY LOOKS LIKE IT COULD BE THE LAST REALLY ACTIVE DAY... ESPLY IF THURSDAY TURNS OUT TO BE A DUD AND AMS IS STILL PRIMED... BEFORE THE DRY WLY FLOW SETS IN FOR THE WEEKEND. THIS LOOKS LIKE IT COULD BE YET ANOTHER PROLONGED DRY SPELL...LASTING AT LEAST SEVERAL DAYS. UPDATES HAVE ALREADY BEEN ISSUED FOR THE CURRENT SHORT TERM TRENDS... NO FURTHER CHANGES NEEDED. PREVIOUS DISCUSSION STILL IN ORDER. PREVIOUS DISCUSSION... ISOLATED THUNDERSTORMS OVER THE HIGHER TERRAIN OF ARIZONA THIS AFTERNOON REFLECT PRETTY GOOD MOISTURE AVAILABILITY BUT MODEST INSTABILITY. AN INVERTED TROUGH OVER SONORA MOVING NORTHWESTWARD WILL HELP TO SPREAD ADDITIONAL MOISTURE OVER ARIZONA TONIGHT WITH THE GRADIENT OVER FAR SOUTHEAST CALIFORNIA. MEANWHILE...THERE MAY BE A SECONDARY DISTURBANCE NEAR THE MEXICAN BORDER AIDING STORM ACTIVITY NEAR AND SOUTH OF NOGALES AND DOUGLAS. THE 12Z GFS KEEPS THE MAIN INVERTED TROUGH SOUTH OF THE MEXICAN BORDER BUT TRACKS THE SECONDARY DISTURBANCE...POSSIBLY AND ARTIFACT OF CONVECTION...INTO SOUTHEAST ARIZONA. WITH THE INVERTED TROUGH BRUSHING OUR AREA ALONG WITH THE OTHER DISTURBANCE...KEPT SLIGHT CHANCE POPS GOING OVER THE ARIZONA ZONES OVERNIGHT. A JET STREAK ASSOCIATED WITH AN UPPER LEVEL PERTURBATION WILL TRACK OVER SOUTHERN ARIZONA THURSDAY. THERE MAY BE SOME DIFFLUENCE JUST AHEAD OF THAT WAVE WHICH COULD ALSO AID VERTICAL MOTIONS. FORECAST SOUNDINGS CONTINUE TO SHOW IMPROVED CAPE DUE TO SOME COOLING ALOFT. NUDGED THE POPS UPWARD FOR THE SOUTH-CENTRAL DESERTS THURSDAY. WIND PROFILES DONT LOOK VERY STRONG SO ORGANIZED STORM DEVELOPMENT IS NOT ANTICIPATED. HOWEVER...ANY STORMS THAT FORM WILL BE CAPABLE OF AT LEAST BRIEF HEAVY RAIN AND STRONG WINDS. LINGERING MOISTURE FRIDAY KEEPS THE STORM THREAT GOING OVER THE ARIZONA ZONES AS THE MAIN SYNOPTIC TROUGH MOVES THROUGH THE NORTHWEST STATES. GFS HAS SLOWED DOWN THE EASTWARD RETREAT OF MOISTURE AND THERE WILL BE A LINGERING THREAT SATURDAY OVER ZONE 24. OVERALL...IT APPEARS SOUTHEAST CALIFORNIA WILL BE DRY. COOLER HIGH TEMPERATURES ARE EXPECTED THE NEXT COUPLE DAYS WITH LITTLE CHANGE SATURDAY. SUNDAY THROUGH WEDNESDAY...THE LARGE SCALE UPPER TROUGH/LOW IS STILL EXPECTED TO MOVE ACROSS THE WESTERN STATES THIS WEEKEND AND SCOUR OUT THE MOISTURE. REMOVED POPS ALTOGETHER FROM THE FORECAST AREA SUNDAY ONWARD. HIGHS WILL GRADUALLY REBOUND NEXT WEEK BUT SHOULD STAY CLOSE TO THE AVERAGES FOR MID AUGUST. && .AVIATION... KPHX AND KIWA... ISOLD CONVECTION LIKELY TO AFFECT THE N VALLEY REST OF THIS EVENING UNTIL ABOUT 07Z...WITH ONLY AN OUTSIDE THREAT AT KIWA/KPHX. WILL NOT INCLUDE IN TAFS AT THIS TIME...BUT WILL INCLUDE CB CLOUDS. TOMORROW AFTN/EVENING APPEARS AS IF IT MAY BE MORE ACTIVE WITH BETTER TSTM COVERAGE AS SOME UPPER LEVEL DYNAMICS POTENTIALLY COME INTO PLAY. FOR NOW...WILL JUST INCLUDE CB CLOUDS AS WE ARE TOO UNCERTAIN OF TIMING TO INCLUDE ANY PROB GROUPS. AWAY FROM ANY GUSTY TSTM OUTFLOWS...WINDS WILL BLOW GENERALLY IN TYPICAL DIURNAL PATTERNS. KIPL AND KBLH... TYPICAL DIURNAL WINDS ANTICIPATED THRU 06Z FRI. TSTM THREAT WILL BE MINIMAL ON THU EVENING...WITH PERHAPS A SLIGHTLY HIGHER RISK AT KBLH...TOO LOW AT THIS TIME TO INCLUDE ANY MENTION IN TAF...BUT IT DOES BEAR WATCHING. AVIATION DISCUSSION NOT UPDATED FOR AMENDED TAFS. && .FIRE WEATHER... SATURDAY THROUGH WEDNESDAY... DRY AIR IS EXPECTED TO SPREAD EAST FROM SOUTHEAST CALIFORNIA ACROSS MOST OF THE AREA SATURDAY. ONLY SOME LINGERING CLOUDINESS IS EXPECTED OVER SOUTH-CENTRAL ARIZONA SATURDAY WITH A SLIGHT CHANCE OF LINGERING SHOWERS AND THUNDERSTORMS OVER THE HIGHER TERRAIN EAST OF THE GREATER PHOENIX AREA. SUNNY SKIES ARE EXPECTED OVER SOUTHEAST CALIFORNIA AND SOUTHWEST ARIZONA SATURDAY. DRY AIR WITH MINIMUM RELATIVE HUMIDITY BELOW 15 PERCENT...MOSTLY CLEAR NIGHTS...AND SUNNY DAYS ARE EXPECTED SUNDAY THROUGH WEDNESDAY. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...NONE. CA...NONE. && NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX DISCUSSION...ESTLE/AJ AVIATION...ESTLE FIRE WEATHER...ELLIS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE PHOENIX AZ 535 AM MST WED AUG 12 2009 AZZ020>028-CAZ030>033-131245- LOWER COLORADO RIVER VALLEY AZ-WEST CENTRAL DESERTS- NORTHWEST MARICOPA COUNTY-GREATER PHOENIX AREA- SOUTHERN GILA COUNTY/TONTO NATIONAL FOREST FOOTHILLS- YUMA/MARTINEZ LAKE AND VICINITY-SOUTHWEST DESERTS- SOUTHWEST MARICOPA COUNTY-NORTHWEST AND NORTH CENTRAL PINAL COUNTY- JOSHUA TREE NATIONAL PARK-LOWER COLORADO RIVER VALLEY CA- RIVERSIDE COUNTY/EASTERN DESERTS-IMPERIAL COUNTY- 535 AM MST WED AUG 12 2009 /535 AM PDT WED AUG 12 2009/ THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF EAST-CENTRAL ARIZONA...EXTREME SOUTHWEST ARIZONA...EXTREME WEST-CENTRAL ARIZONA... SOUTH-CENTRAL ARIZONA...SOUTHWEST ARIZONA...WEST-CENTRAL ARIZONA... EXTREME SOUTHEAST CALIFORNIA AND SOUTHEAST CALIFORNIA. .DAY ONE...TODAY AND TONIGHT EXPECT ISOLATED THUNDERSTORMS TO DEVELOP DURING THE LATE AFTERNOON AND EVENING HOURS. MOST OF THE STORMS WILL BE OVER THE HIGHER TERRAIN OF SOUTH CENTRAL ARIZONA. THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING HEAVY RAIN...OCCASIONAL LIGHTNING...STRONG AND GUSTY WINDS WITH AREAS OF DENSE BLOWING DUST. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO DEVELOP THURSDAY AND FRIDAY ACROSS SOUTH CENTRAL ARIZONA...WITH ISOLATED STORMS IN SOUTHWEST ARIZONA. THE STRONGEST STORMS WILL BE CAPABLE OF PRODUCING HEAVY RAIN...OCCASIONAL LIGHTNING...STRONG AND GUSTY WINDS WITH AREAS OF DENSE BLOWING DUST. ISOLATED THUNDERSTORMS WILL BE LIMITED TO THE HIGHER ELEVATIONS OF SOUTH CENTRAL ARIZONA SATURDAY THROUGH TUESDAY. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. SPOTTER ACTIVATION MAY BECOME NECESSARY THURSDAY EVENING IN THE GREATER PHOENIX AREA. NATIONAL WEATHER SERVICE PHOENIX IS ON THE INTERNET AT WEATHER.GOV/PHOENIX
The Phoenix radar (KIWA), 70 km away, was scanning. The volume nearest the first event began at 05:22 UTC.
2 thunderstorm wind. Local standard time, as filed.
Microburst wind speed at Luke AFB was measured at 60 knots. Blowing dust was also reported resulting in 1/4 mile visibility.
Two trees were uprooted at Glendale and Litchfield avenues. The larger tree was about 10 to 12 inches in diameter.
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, August 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: 181679, 181680.