Abundant moisture, favorable southeasterly flow aloft, and terrain influences resulted in isolated showers and thunderstorms across southeast Arizona. Some of the storms produced heavy rainfall and strong winds.
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 TWC wrote it up.
Abundant moisture, favorable southeasterly flow aloft, and terrain influences resulted in isolated showers and thunderstorms across southeast Arizona. Some of the storms produced heavy rainfall and strong winds.
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 Tucson, AZ wrote its last area forecast discussion before the first event at Aug 21, 2:43 PM MST, 4 hours 27 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 243 PM MST SUN AUG 21 2011 .SYNOPSIS...EXPECT ISOLATED SHOWERS AND THUNDERSTORMS THIS EVENING WITH LESS ACTIVITY NEXT WEEK AND HOTTER TEMPERATURES THROUGH THE WEEK. && .DISCUSSION...RADAR INDICATES A FEW ISOLATED THUNDERSTORMS AND SHOWERS OVER CENTRAL PIMA AND EAST CENTRAL COCHISE COUNTIES. TODAYS 12Z SOUNDING INDICATES BOTH WARMING AND DRYING THROUGH 600MB FROM YESTERDAY. GIVEN THE DECREASE IN MOISTURE ANTICIPATE ANY EVENING CONVECTION AND SHOWERS TO SUBSIDE AFTER 8PM. MON-THUR...WITH THE WESTWARD MOVEMENT OF THE 500MB HIGH NUMERICALS INDICATE A SIGNIFICANT CUT OFF OF MOISTURE THROUGH THURS AND THICKNESS RISES INTO FRI. TRENDS POINT TOWARDS RISES OF 6-7 DEGREES ABOVE NORMAL BY TUE INTO THUR. EXPECT FRIDAYS HIGH DROPPING OFF COUPLE OF DEGREES WITH INCREASED CLOUD COVER AND A GREATER CHANCE OF AFTERNOON CONVECTION AS THE HIGH SETS UP CENTERED OVER THE FOUR CORNERS REGION. && .AVIATION...SCT-BKN CLD BASES 12-15KFT AGL. ISOLD SHRA/TS DVLPG AFT 18Z...MAINLY NEAR MTNS. SFC WND MAINLY LESS THAN 10KTS EXCEPT PK WND NR 45KTS WITH TSRA. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...EXPECT ISOLATED TO SCATTERED THUNDERSTORMS TO CONTINUE WITH HOTTER TEMPERATURES DURING THE COMING WEEK. NORMAL DIURNAL WIND TRENDS WILL OCCUR...EXCEPT STRONG AND GUSTY WINDS WILL PREVAIL NEAR THUNDERSTORMS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. MCLEOD WEATHER.GOV/TUCSON
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE TUCSON AZ 940 PM MST SAT AUG 20 2011 AZZ510>515-210600- WHITE MOUNTAINS OF GRAHAM AND GREENLEE COUNTIES- GALIURO AND PINALENO MOUNTAINS-CHIRICAHUA MOUNTAINS- DRAGOON AND MULE AND HUACHUCA AND SANTA RITA MOUNTAINS- CATALINA AND RINCON MOUNTAINS-BABOQUIVARI MOUNTAINS- 940 PM MST SAT AUG 20 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA. .DAY ONE...TONIGHT NO WEATHER HAZARDS EXPECTED. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ARE EXPECTED EACH DAY. THE MAIN THREATS WILL BE LOCALLY HEAVY RAINFALL AND WIND GUSTS OF 40 TO 50 MPH WITH THE STRONGER THUNDERSTORMS. PLEASE NOTE THAT EVEN MODERATE RAINFALL OVER THE RECENT BURN AREAS COULD RESULT IN FLASH FLOODING. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. AZZ503-504-506>509-210600- UPPER SANTA CRUZ RIVER VALLEY/ALTAR VALLEY-TUCSON METRO AREA- SOUTHEAST PINAL COUNTY-UPPER SAN PEDRO RIVER VALLEY-EASTERN COCHISE COUNTY BELOW 5000 FEET-UPPER GILA RIVER VALLEY- 940 PM MST SAT AUG 20 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA. .DAY ONE...TONIGHT NO WEATHER HAZARDS EXPECTED. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY THE CHANCE OF DAILY THUNDERSTORMS WILL CONTINUE INTO NEXT WEEK. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. AZZ501-502-505-210600- WESTERN PIMA COUNTY-TOHONO O'ODHAM NATION- SOUTH CENTRAL PINAL COUNTY- 940 PM MST SAT AUG 20 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST ARIZONA. .DAY ONE...TONIGHT NO WEATHER HAZARDS EXPECTED. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY ONLY A SLIGHT CHANCE OF AFTERNOON EVENING THUNDERSTORMS SUNDAY INTO EARLY NEXT WEEK AS DRIER AIR PUSHES IN FROM THE WEST. HIGH PRESSURE ALOFT WILL BUILD OVER THE AREA NEXT WEEK BRINGING MUCH HOTTER DAYTIME TEMPERATURES. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. WEATHER.GOV/TUCSON
The Tucson radar (KEMX), 93 km away, was scanning. The volume nearest the first event began at 02:08 UTC.
1 thunderstorm wind, 1 flash flood. Local standard time, as filed.
Thunderstorm winds downed power poles on Central Highway between Latimer Road and Hopkins Road in Elfrida.
Heavy rainfall resulted in flash flooding along Central Highway in McNeal. Law Enforcment reported three cars stranded in rushing water at the intersection of Davis Road and Central Highway with two additional cars swept down Davis Road. No injuries were reported.
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, August 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: 343932, 343938.