High pressure east of Arizona forced moisture into the area from the east and south, which led to the development of isolated afternoon and evening thunderstorms.
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.
High pressure east of Arizona forced moisture into the area from the east and south, which led to the development of isolated afternoon and evening thunderstorms.
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 11, 1:45 PM MST, 6 hours 45 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 145 PM MST SUN JUL 11 2004 SOUTHEAST ARIZONA FORECAST DISCUSSION .SYNOPSIS...HIGH PRESSURE EXTENDING THROUGH THE AREA FROM THE EAST WILL GUIDE MORE MOISTURE INTO ARIZONA FROM THE SOUTH AND EAST. EXPECT THE CHANCE OF SHOWERS AND THUNDERSTORMS TO INCREASE THROUGH THE WEEK. COVERAGE AND INTENSITY OF STORMS WILL BE ENHANCED DURING THE MIDDLE OF THE WEEK AS AN UPPER LEVEL DISTURBANCE MOVES IN FROM THE EAST UNDER THE HIGH. && .DISCUSSION...MORNING KTUS SOUNDING SHOWED 1.2 PRECIPITABLE WATER WITH GOES SOUNDER ESTIMATES SHOWING THE SOUTHERN HALF OF THE STATE AT OR ABOVE THIS MARK...EXTENDING INTO EVEN DEEPER MOISTURE THROUGH SONORA. SOME DEBRIS IN THE MORNING...BUT PLENTY OF SOLAR INSOLATION NOW FOR STORMS TO FIRE ON SCHEDULE OVER EASTERN MOUNTAINS. DEWPTS ARE NOT AT THEIR BEST...LOWER TO MID 50S...(COULD BE KIND OF DRY MICROBURSTY) BUT FLOW IS STARTING TO VEER AROUND TO THE FAVORED EASTERLY DIRECTION FOR OUTFLOW FROM THE HIGHER TERRAIN. EARLY AFTERNOON SHOWING A WEAK CELL MOVEMENT FROM THE EAST WHICH SHOULD INCREASE THROUGH THE AFTERNOON AND EVENING HOURS. ALSO...WITH MOISTURE TRENDS AS THEY ARE...LOCALLY HEAVY RAIN IS BY NO MEANS EXCLUDED FROM CONSIDERATION. HIGH CENTER CONSOLIDATING TO OUR NORTHEAST OVER THE NEXT 48 HOURS...GIVING A MORE DEFINITE EASTERLY FLOW AND ALLOWING EASTERLY IMPULSES TO RIDE A LATITUDE CLOSER TO OURS. ONE SUCH ANIMAL CURRENTLY NEAR THE SOUTHERN TIP OF TEXAS COULD MAKE IT BY MID DAY WEDNESDAY THROUGH SONORA...CLIPPING SOUTHERN ARIZONA AND LIKELY HAVING FURTHER INFLUENCE WITH STRONG OUTFLOWS FROM ORGANIZED CONVECTION. IN ADDITION...INCREASING PRESSURE DIFFERENTIAL UP THE GULF OF CALIFORNIA BECOMING SUCH THAT A SURGE INTO THE LOWER DESERTS IS EXPECTED IN THE NEXT 24 TO 36 HOURS. NICE DEEP EASTERLIES IN MEXICAN SOUNDINGS ALONG THE PACIFIC COAST...STARTING TO TURN AND GAIN A SOUTHERLY COMPONENT BY MID GULF. ONE FINAL NOTE OF INTEREST...NAME IOP STARTS AT 00Z. && .FIRE WEATHER...HIGH CENTER STRENGTHENING TO OUR EAST WILL BRING MORE MOISTURE INTO SOUTHEAST ARIZONA FROM THE SOUTH AND EAST WITH A CHANCE OF SHOWERS AND THUNDERSTORMS IMPROVING THROUGH THE WEEK. DIURNAL WIND TRENDS WILL BE COMPLICATED BY THE GUSTY OUTFLOWS FROM THESE THUNDERSTORMS...WHILE RELATIVE HUMIDITIES ARE EXPECTED TO GREATLY INCREASE AS THE ATMOSPHERE MOISTENS UP TO SEASONAL LEVELS. && .CLIMATE...FOR THE 3RD DAY IN A ROW...THE AVERAGE DEWPOINT AT TUCSON INTERNATIONAL AIRPORT WAS AT OR ABOVE 54 DEGREES YESTERDAY. THUS...THE FIRST MONSOON DAY OF 2004 IN TUCSON WAS JULY 8TH. THE AVERAGE 1ST MONSOON DATE IS JULY 3RD. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. MEYER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TUCSON AZ 1127 AM MST SUN JUL 11 2004 AZZ019-029>035-120700- NORTHERN GREENLEE COUNTY-UPPER GILA RIVER VALLEY-COCHISE COUNTY- SOUTHEAST PINAL COUNTY-TUCSON METRO/MARANA/GREEN VALLEY- SANTA CRUZ COUNTY-TOHONO OODHAM NATION-WESTERN PIMA COUNTY- 1127 AM MST SUN JUL 11 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA .DAY ONE...TODAY SYNOPSIS...THE MONSOON MOISTURE BOUNDARY HAS BEGUN TO SHIFT WEST ACROSS SOUTHEAST ARIZONA. ALTHOUGH INSTABILITY AND MID LEVEL STEERING FLOW REMAINS WEAK...THE WESTWARD SHIFT IN THE BOUNDARY SUGGESTS THAT THE STORMS TODAY WILL BE SOMEWHAT BETTER ORGANIZED. THE GREATEST THREAT OF ONE INCH RAINS WILL BE OVER THE MOUNTAINS OF SANTA CRUZ AND COCHISE COUNTIES. THERE IS ALSO A RISK OF AN ISOLATED SEVERE THUNDERSTORM OR TWO TODAY...WITH THE MAIN THREAT FROM STRONG DOWNBURST WINDS. DISCUSSION...THE OVERALL MONSOON PATTERN IS UNDERGOING REALIGNMENT AS THE UPPER LEVEL HIGH SHIFTS TOWARD THE FOUR CORNERS REGION AND A LARGE UPPER LEVEL LOW MOVES ACROSS CENTRAL MEXICO. MID LEVEL WINDS WERE STILL WEAK THIS MORNING BUT THE ONGOING REALIGNMENT WILL INCREASE EAST FLOW TO AROUND 15 MPH BY TONIGHT. THIS WILL CAUSE THE STORMS TODAY TO BECOME SOMEWHAT LONGER-LIVED...ALTHOUGH THEY WILL NOT BE PARTICULARLY ORGANIZED. THE BOUNDARY LAYER REMAINS ON THE DRY SIDE...SO THE STRONGER THUNDERSTORM OUTFLOWS WILL BE CAPABLE OF PRODUCING WINDS GUSTS APPROACHING SEVERE LEVELS AND LOCALIZED BLOWING DUST. THE GRADUAL MOISTURE INCREASE COULD AGAIN CAUSE A FEW HEAVY DOWNPOURS SIMILAR TO WHAT PARTS OF SOUTHEAST PIMA AND SANTA CRUZ COUNTIES HAVE EXPERIENCED SINCE THURSDAY. THE RISK WILL SHIFT WEST OVERNIGHT...WITH OUTFLOWS AND ISOLATED THUNDERSTORMS PROBABLY MAKING IT ALL THE WAY INTO THE WESTERN DESERTS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY. THE RISK WILL INCREASE FOR MORE NUMEROUS AND POSSIBLY STRONG THUNDERSTORMS THROUGH WEDNESDAY. THE LARGE UPPER LEVEL DISTURBANCE OVER CENTRAL MEXICO WILL MOVE TO THE GULF OF CALIFORNIA BY TUESDAY BEFORE TURNING NORTHWEST TOWARD SOUTHERN CALIFORNIA. THIS SYSTEM HAS ALREADY TAPPED INTO A TROPICAL DISTURBANCE ALONG THE SOUTHWEST COAST OF MEXICO...AND CONDITIONS WILL BE FAVORABLE FOR A SURGE OF MOISTURE UP THE GULF OF CALIFORNIA AND INTO THE DESERTS ON MONDAY AND TUESDAY. THERE IS A CHANCE THAT CONSIDERABLE CLOUD COVER WILL HOLD DOWN THE AMOUNT OF INSTABILITY AND THUS REDUCE THE THREAT OF SEVERE THUNDERSTORMS AND FLASH FLOODING ON ANY GIVEN DAY. HOWEVER...THE UPCOMING WEEK GENERALLY LOOKS ACTIVE IN TERMS OF THUNDERSTORM DEVELOPMENT. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. PYTLAK
The Tucson radar (KEMX), 58 km away, was scanning. The volume nearest the first event began at 03:28 UTC.
1 thunderstorm wind. Local standard time, as filed.
A power pole was downed by thunderstorm wind gusts near the intersection of River and Oracle.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2004Every state in 2004This day in weather historyWarnings in Arizona, July 2004
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: 5415714.