A weakening upper level disturbance over Northern Chihuahua, Mexico moved into Southeast Arizona where plenty of moisture was already in place due to tropical storm Blas. Precipitable water was almost double the normal level for mid-July thanks to these features.
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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.
A weakening upper level disturbance over Northern Chihuahua, Mexico moved into Southeast Arizona where plenty of moisture was already in place due to tropical storm Blas. Precipitable water was almost double the normal level for mid-July thanks to these features. An upper air sounding from late morning showed an increase in the east wind shear causing the initial storms to train. This led to the flooding of areas in Santa Cruz county.
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 14, 9:00 PM MST, 2 hours 50 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 900 PM MST WED JUL 14 2004 SOUTHEAST ARIZONA FORECAST DISCUSSION .SYNOPSIS...HIGH PRESSURE ALOFT CENTERED OVER COLORADO WILL KEEP A MOIST EAST TO SOUTHEAST FLOW INTO ARIZONA THIS WEEK. THE RISK OF THUNDERSTORMS SHOULD DECREASE SOMEWHAT OVER THE WEEKEND AS THE UPPER HIGH MOVES SOUTH AND CUTS OFF SOME OF THE MOISTURE SUPPLY. && .DISCUSSION...MAIN UPPER LEVEL DIFFLUENT AREA TO OUR NORTH FOR EASTERLY IMPULSE MOVING THROUGH. CONVECTION FIRED BY EARLY AFTERNOON OVER HIGH TERRAIN UNDER SUNSHINE IN EASTERN AREAS (GREENLEE GRAHAM AND COCHISE COUNTIES). OUTFLOWS FROM THIS STRONG AND WET ACTIVITY FAILED TO TRIGGER MUCH IN COOLER CLOUD CHOKED AREAS FURTHER WEST. EXCEPTION MAY BE OVERNIGHT TONIGHT WITH CENTRAL AND WESTERN PIMA COUNTY. AS THE IMPULSE MOVES BODILY THROUGH...EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS OVERNIGHT...ESPECIALLY WEST OF TUCSON. WELL HAVE TO CONTINUE TO WATCH FOR HEAVY RAINFALL...BUT IN GENERAL THE AREA OF COVERAGE IS NOT EXPECTED TO BE ENOUGH TO WARRANT A FLASH FLOOD WATCH. THE WATCH WAS CANCELLED AT 7PM. THURSDAY COULD ACTUALLY END UP BEING A BETTER DAY FOR STORMS WITH A BETTER BALANCE BETWEEN MOISTURE AND HEATING. AS STATED BEFORE...BY FRIDAY THE FORECAST CYCLE SHOWS A SLOW DOWNTURN IN ACTIVITY INTO THE WEEKEND. THIS DUE TO THE UPPER HIGH OVER COLORADO MOVING TO THE SOUTH AND REORIENTING THE FLOW MORE FROM THE SOUTH AND EVEN SOUTHWEST. IN ADDITION...SOME DRIER AIR IS WRAPPING INTO PORTIONS OF NEW MEXICO. EVEN SO...WITH THE AMOUNT OF MOISTURE WE HAVE IN PLACE (00Z KTUS SOUNDING SHOWED 1.67...ALMOST TOO HIGH?) WE SHOULD HAVE ENOUGH TO RECIRCULATE FOR AWHILE EVEN IF SOME GETS CHOKED OFF. && .FIRE WEATHER...MONSOON TYPE HUMIDITIES WILL CONTINUE WITH WINDS REMAINING ON THE LIGHT SIDE EXCEPT NEAR THUNDERSTORMS. LOCALLY HEAVY RAINFALL WILL ALSO BE A CONCERN NEAR STORM CORES. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. MEYER
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TUCSON AZ 1154 AM MST WED JUL 14 2004 AZZ019-029-030-033>035-150700- NORTHERN GREENLEE COUNTY-UPPER GILA RIVER VALLEY-COCHISE COUNTY- SOUTHEAST PINAL COUNTY-TUCSON METRO/MARANA/GREEN VALLEY- SANTA CRUZ COUNTY- 1154 AM MST WED JUL 14 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA .DAY ONE...TODAY ...FLASH FLOOD WATCH 200 PM UNTIL 1000 PM... SYNOPSIS...THE RISK OF EXCESSIVE RAINFALL IS HIGH THIS AFTERNOON AND EVENING. A WEAKENING UPPER LEVEL DISTURBANCE OVER NORTHERN CHIHUAHUA WILL MOVE INTO SOUTHEAST ARIZONA TONIGHT WHERE TROPICAL MOISTURE IS IN PLACE. CLOUD COVER AND RATHER WARM TEMPERATURES ALOFT WILL KEEP THE RISK OF SEVERE THUNDERSTORMS BELOW CLIMATOLOGY... HOWEVER ISOLATED SMALL HAIL AND WET MICROBURSTS ARE POSSIBLE WITH THE STRONGEST STORMS. DISCUSSION...TROPICAL MOISTURE MOVED NORTH INTO THE REGION OVER THE PAST 36 HOURS FROM THE GULF OF CALIFORNIA. PRECIPITABLE WATER IS ALMOST DOUBLE THE NORMAL LEVEL FOR MID JULY. ISOLATED THUNDERSTORMS WERE ALREADY DEVELOPING OVER SOUTHEAST ARIZONA...DESPITE CONSIDERABLE CLOUD COVER. THE UPPER AIR SOUNDING FROM LATE THIS MORNING ALSO SHOWED AN INCREASE IN EAST WIND SHEAR...WHICH IS CAUSING THE INITIAL STORMS TO TRAIN. ALL OF THIS STRONGLY SUGGESTS A POTENTIALLY SERIOUS FLASH FLOOD SITUATION. THE LACK OF DAYTIME HEATING SHOULD KEEP STORM UPDRAFTS FROM BECOMING TOO STRONG...BUT THE INCREASE IN MID LEVEL WIND SHEAR AND EXCESSIVE MOISTURE CONTENT IN THE ATMOSPHERE COULD CAUSE A COUPLE OF STORMS TO PRODUCE WET MICROBURSTS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THE RISK OF STRONG THUNDERSTORMS WILL DIMINISH SOMEWHAT BY THE END OF THE WEEK AS HIGH PRESSURE OVER SOUTHERN COLORADO SHIFTS INTO NEW MEXICO. THIS WILL REDUCE EAST FLOW OVER THE REGION AND WILL CAUSE SOME WARMING ALOFT. AN UPSWING IS THEN POSSIBLE EARLY NEXT WEEK AS THE HIGH AGAIN TRIES TO SHIFT BACK TO THE NORTH. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. AZZ031-032-150700- TOHONO OODHAM NATION-WESTERN PIMA COUNTY- 1154 AM MST WED JUL 14 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTH CENTRAL ARIZONA .DAY ONE...TODAY ...FLASH FLOOD WATCH 600 PM UNTIL 300 AM... SYNOPSIS...THE RISK OF EXCESSIVE RAINFALL IS HIGH THIS AFTERNOON AND EVENING. A WEAKENING UPPER LEVEL DISTURBANCE OVER NORTHERN CHIHUAHUA WILL MOVE INTO SOUTHEAST ARIZONA TONIGHT WHERE TROPICAL MOISTURE IS IN PLACE. CLOUD COVER AND RATHER WARM TEMPERATURES ALOFT WILL KEEP THE RISK OF SEVERE THUNDERSTORMS BELOW CLIMATOLOGY... HOWEVER ISOLATED SMALL HAIL AND WET MICROBURSTS ARE POSSIBLE WITH THE STRONGEST STORMS. DISCUSSION...TROPICAL MOISTURE MOVED NORTH INTO THE REGION OVER THE PAST 36 HOURS FROM THE GULF OF CALIFORNIA. PRECIPITABLE WATER IS ALMOST DOUBLE THE NORMAL LEVEL FOR MID JULY. ISOLATED THUNDERSTORMS WERE ALREADY DEVELOPING OVER SOUTHEAST ARIZONA...DESPITE CONSIDERABLE CLOUD COVER. THE UPPER AIR SOUNDING FROM LATE THIS MORNING ALSO SHOWED AN INCREASE IN EAST WIND SHEAR...WHICH IS CAUSING THE INITIAL STORMS TO TRAIN. ALL OF THIS STRONGLY SUGGESTS A POTENTIALLY SERIOUS FLASH FLOOD SITUATION. THE LACK OF DAYTIME HEATING SHOULD KEEP STORM UPDRAFTS FROM BECOMING TOO STRONG...BUT THE INCREASE IN MID LEVEL WIND SHEAR AND EXCESSIVE MOISTURE CONTENT IN THE ATMOSPHERE COULD CAUSE A COUPLE OF STORMS TO PRODUCE WET MICROBURSTS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THE RISK OF STRONG THUNDERSTORMS WILL DIMINISH SOMEWHAT BY THE END OF THE WEEK AS HIGH PRESSURE OVER SOUTHERN COLORADO SHIFTS INTO NEW MEXICO. THIS WILL REDUCE EAST FLOW OVER THE REGION AND WILL CAUSE SOME WARMING ALOFT. AN UPSWING IS THEN POSSIBLE EARLY NEXT WEEK AS THE HIGH AGAIN TRIES TO SHIFT BACK TO THE NORTH. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES. PYTLAK
The Tucson radar (KEMX), 46 km away, was scanning. The volume nearest the first event began at 06:47 UTC.
1 flash flood. Local standard time, as filed.
A county official reported that the Vereda Nebline Road was washed out and was impassable.
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: 5415768.