An upper-level disturbance rotated into southeast Arizona, around a strong ridge of high pressure over the southern plains. As the disturbance moved northwest out of Sonora, Mexico, it interacted with a rich moisture supply to produce scattered thunderstorms across southeast Arizona.
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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 TWC wrote it up.
An upper-level disturbance rotated into southeast Arizona, around a strong ridge of high pressure over the southern plains. As the disturbance moved northwest out of Sonora, Mexico, it interacted with a rich moisture supply to produce scattered thunderstorms across southeast Arizona.
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 Jul 2, 2:40 PM MST, 50 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 240 PM MST THU JUL 2 2009 .SYNOPSIS...ABUNDANT MOISTURE WILL BRING SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ACROSS SOUTHEAST ARIZONA THROUGH INDEPENDENCE DAY. AS A TROUGH PROGRESSES TO THE WEST COAST...DRIER AIR WILL MOVE INTO ARIZONA NEXT WEEK FOR A DECREASE IN MOISTURE AND THUNDERSTORM ACTIVITY. && .DISCUSSION...SYNOPTIC PATTERN HAS A HIGH CENTERED IN NORTHERN NEW MEXICO WITH MOISTURE ROTATING CLOCKWISE FROM MEXICO INTO ARIZONA. THIS SITUATION PROVIDES A WEAK DIVERGENT FLOW ALOFT OVER SOUTHERN ARIZONA WHICH HAS HELPED SUPPORT THE LATE EVENING AND EARLY MORNING RAIN SHOWERS THE PAST TWO DAYS. ADDITIONALLY A WEAK UPPER LEVEL LOW IS LOCATED IN SOUTHERN CHIHUAHUA MEXICO AND MOVING TOWARDS THE NORTHWEST. CONVECTIVE ACTIVITY IS USUALLY NOT ASSOCIATED WITH THE CENTER OF THESE LOWS...BUT IN THE DIVERGENT ZONE AHEAD OF THE SYSTEM. SATELLITE IMAGERY SHOWS THIS CONVECTIVE ACTIVITY BEING ENHANCED AHEAD OF THE SYSTEM NOW AT 2 PM. THE MODELS ARE NOT PICKING UP THE EXACT DETAILS ASSOCIATED WITH THIS LOW...BUT DO HAVE THE GENERAL IDEA OF ORGANIZED CONVECTION MOVING INTO ARIZONA OR NEW MEXICO EARLY FRIDAY MORNING. LIKEWISE MOS POPS ARE IN THE 40-60 RANGE WHICH IS WELL ABOVE NORMAL. GIVEN THE ABOVE SITUATION HAVE SIGNIFICANTLY INCREASED POPS FOR TONIGHT AND TOMORROW MORNING ACROSS EASTERN PIMA...PINAL...SANTA CRUZ...COCHISE...GRAHAM AND GREENLEE COUNTIES. LIKEWISE INCREASED QPF AMOUNTS AND DROPPED HIGH TEMPERATURES SLIGHTLY FOR TOMORROW. AS A MID-LATITUDE TROUGH PROGRESSES TO THE WEST COAST...A WESTERLY FLOW WITH DRIER AIR IS PROGGED TO INFLUENCE ARIZONA EARLY NEXT WEEK. THE HIGH OVER THE SOUTHWEST MOVES SOUTH INTO NORTHERN MEXICO AS THIS TROUGH APPROACHES. THE MODELS VARY ON THE TIMING OF THIS DRY AIR MOVING INTO US. THE GFS IS FASTER IN DRYING US OUT...THE NAM KEEPS THE MOISTURE LONGER. GIVEN LARGE SCALE CHANGES HAPPEN SLOWLY...EXPECT DRIER AIR TO START REDUCING THE CONVECTION ON SUNDAY. DO NOT EXPECT THE ATMOSPHERE TO DRY OUT ENTIRELY...BUT THUNDERSTORMS WILL GO FROM SCATTERED TO MORE ISOLATED. LIKEWISE AS THE ATMOSPHERE DRIES OUT A BIT...MAXIMUM TEMPERATURES WILL INCREASE SLIGHTLY. && .AVIATION...SCATTERED TSRA/SHRA EXPECTED TONIGHT AND EARLY TOMORROW. EXPECTING DEVELOPMENT IN NORTHERN MEXICO WHICH WILL MOVE INTO SOUTHERN ARIZONA. THUNDERSTORMS WILL HAVE ERRATIC WIND GUSTS TO 40 MPH...LIGHTNING AND LOCALLY HEAVY RAIN WITH REDUCED VISIBILITIES DOWN TO 2SM FOR A BRIEF PERIOD OF TIME. CLOUD BASES GENERALLY 8-12K FT AGL WITH CEILINGS NEAR 3K FT AGL AROUND THE THUNDERSTORMS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A MOIST ATMOSPHERE ACROSS SOUTHEAST ARIZONA WILL RESULT IN SCATTERED THUNDERSTORMS THROUGH THE WEEKEND. A TROUGH MOVING TOWARDS THE WEST COAST WILL SHIFT A DRIER WESTERLY FLOW INTO ARIZONA NEXT WEEK. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. GWS WEATHER.GOV/TUCSON
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TUCSON AZ 1130 AM MST THU JUL 2 2009 AZZ019-029>035-031200- NORTHERN GREENLEE COUNTY-SOUTHEAST PINAL COUNTY- UPPER GILA RIVER VALLEY-WESTERN PIMA COUNTY-TOHONO OODHAM NATION- TUCSON METRO/MARANA/GREEN VALLEY-SANTA CRUZ COUNTY-COCHISE COUNTY- 1130 AM MST THU JUL 2 2009 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL ARIZONA AND SOUTHEAST ARIZONA. .DAY ONE...TODAY AND TONIGHT A VERY MOIST AIRMASS OVER SOUTHEAST ARIZONA WILL RESULT IN SCATTERED AFTERNOON AND EVENING THUNDERSTORMS. INITIALLY...STORMS WILL DEVELOP OVER THE LOCATIONS THAT HAVE BEEN RELATIVELY CLOUD FREE THIS MORNING INCLUDING COCHISE...GRAHAM AND GREENLEE COUNTIES...THEN DEVELOP ELSEWHERE DURING THE LATE AFTERNOON. STRONG GUSTY WINDS...SMALL HAIL...AND LOCALLY HEAVY RAIN WILL OCCUR WITH SOME OF THESE STORMS. AN UPPER LEVEL FEATURE MOVING THROUGH NORTHERN MEXICO WILL RESULT IN A LARGE THUNDERSTORM COMPLEX DEVELOPING IN SONORA MEXICO LATE THIS AFTERNOON...AND WILL IN TIME TRACK NORTH INTO AREAS TO THE EAST OF TUCSON THIS EVENING AND OVERNIGHT. THE MAIN THREAT FROM THESE STORMS WILL BE THE POTENTIAL FOR FLASH FLOODING DUE TO HEAVY RAINFALL... WITH LOCALIZED STRONG GUSTY WINDS POSSIBLE NEAR THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY THE UPPER LEVEL HIGH WILL SHIFT EAST THE NEXT COUPLE OF DAYS. ALTHOUGH THIS WILL INTRODUCE DRYING INTO THE AREA FROM THE WEST...ENOUGH MOISTURE WILL BE AROUND FOR ISOLATED TO SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. WEATHER.GOV/TUCSON
The Phoenix radar (KIWA), 148 km away, was scanning. The volume nearest the first event began at 22:30 UTC.
2 thunderstorm wind. Local standard time, as filed.
Thunderstorm winds estimated at 60 mph downed several power poles just north of Ajo.
Severe thunderstorm outflow winds downed power lines near the intersection of Valencia and Mark Rds.
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, July 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: 170953, 170952.