Flash Flood in Arizona, July 29, 2003

Name: Flash Flood in Arizona, July 29, 2003
Start: 2003-07-29T22:00
End: 2003-07-29T23:55
Location: Arizona

July 29, 2003 · NWS TWC · 1 event in 1 county or zone

A strong thunderstorm over Avra Valley produced heavy rainfall. The radar estimated over 3 inches of rainfall over Silver Bell and Wateman Mountains.

Where it happened

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.

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The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 1

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.

What happened

The episode as NWS TWC wrote it up.

A strong thunderstorm over Avra Valley produced heavy rainfall. The radar estimated over 3 inches of rainfall over Silver Bell and Wateman Mountains. A spotter reported Blanco Wash near bankfull with 8 feet of water, and out of banks downstream near Green Acres RV park. A bridge near El Trio Road was overtopped, with an estimated 7 feet of water.

What forecasters said that day

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 29, 9:40 PM MST, 20 minutes earlier.

Area forecast discussion, Jul 29, 9:40 PM MST, 20 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
940 PM MST TUE JUL 29 2003

.SYNOPSIS...ARIZONA WAS CENTERED BETWEEN TWO SYSTEMS...WITH HIGH
PRESSURE TO OUR NORTH AND AN AREA OF LOW PRESSURE OFF THE NORTHERN
BAJA PENINSULA. THE LOW WILL MOVE WEST TONIGHT AND WEDNESDAY...
SWITCHING THE STEERING FLOW TO A MORE SOUTHERLY DIRECTION. THIS WILL
KEEP THE AIRMASS VERY MOIST THE NEXT FEW DAYS...CONTINUING THE
THREAT OF SCATTERED AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS.
HIGH PRESSURE WILL THEN SHIFT EASTWARD OVER NEW MEXICO BY THE
WEEKEND. THIS WILL LEAD TO A GRADUAL DECREASE IN THUNDERSTORMS OVER
THE FAR WESTERN DESERTS BY THE END OF THE WEEK...AS A DRIER AIR MASS
FILTERS INTO THE REGION.

.DISCUSSION...YET ANOTHER VERY ACTIVE AFTERNOON/EVENING ACROSS
SOUTHEAST ARIZONA WITH NUMEROUS WARNINGS. SITUATION HAS IMPROVED
GREATLY ALTHOUGH AREA RADARS CONTINUE TO INDICATE SOME LIGHT TO
MODERATE ACTIVITY STILL OCCURRING OVER PORTIONS OF SOUTHERN ARIZONA.
MOST OF THE ONGOING SHOWERS/THUNDERSTORMS WERE NORTHWEST OF A LINE
FROM FLORENCE...TO ELOY...TO WHY. HOWEVER...THERE HAS ALSO BEEN SOME
REDEVELOPMENT OVER FAR EASTERN PORTIONS OF THE CWA IN SOUTHERN
GREENLEE/GRAHAM COUNTIES AND IN COCHISE COUNTY. EXPECT THE SHOWERS
AND STORMS ASSOCIATED WITH COMPLEX DEVELOPMENT OVER FAR WESTERN
PORTIONS OF THE CWA TO CONTINUE ADVANCING WESTWARD THIS EVENING...
WHILE THE WEAK ACTIVITY OVER THE EAST WILL HAVE A DIFFICULT TIME
SUSTAINING ITSELF AS IT MOVES INTO AN AREA THAT HAD BEEN WORKED OVER
BY EARLIER CONVECTION. THE STORM DEVELOPMENT TODAY OCCURRED ON THE
CONVERGENT FLOW AXIS BETWEEN AN AREA OF HIGH PRESSURE TO OUR NORTH
AND LOW PRESSURE SITUATED TO OUR SOUTHWEST. IN ADDITION...A VORT
LOBE ROTATING AROUND THE LOW MOVED ACROSS THE AREA DURING MAXIMUM
HEATING...HELPING TO INITIATE AND ENHANCE ACTIVITY ACROSS SOUTHERN
ARIZONA.

THE AREA OF LOW PRESSURE IS EXPECTED TO MOVE WEST/NORTHWEST TONIGHT
AND WEDNESDAY...WHILE THE AREA OF HIGH PRESSURE BEGINS TO SHIFT EAST
TOWARDS THE FOUR CORNERS. THIS WILL KEEP SOUTHERN ARIZONA IN A SOUTH
TO SOUTHEAST FLOW PATTERN WITH SUFFICIENT MOISTURE TO MAINTAIN
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS. ONGOING FORECAST HAS
THIS SITUATION COVERED...HOWEVER WILL UPDATE TONIGHT PERIOD TO
FRESHEN THINGS UP A BIT AND FOR REDEVELOPMENT OVER EASTERN PORTIONS
OF THE CWA.  ZELL

.TWC...FLOOD WARNING FOR CENTRAL PIMA COUNTY/ZONE 32 UNTIL 9 AM MST
WEDNESDAY MORNING.

Hazardous weather outlook, Jul 29, 12:20 PM MST, 9 hours 40 minutes before

AZZ019-029>035-301400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1220 PM MST TUE JUL 29 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...A COOL START TO THE DAY WILL BE OVERCOME THIS AFTERNOON
AS TEMPERATURES CLIMB INTO THE NINETIES OVER THE VALLEYS. SOUTHERN
COCHISE COUNTY AND AREAS SOUTH AND WEST OF TUCSON SEEM THE LIKELY
AREA FOR THE STRONGEST STORMS TODAY.

DISCUSSION...

CONVECTION HAS ALREADY BEGUN THIS AFTERNOON AS MOISTURE CONTINUES TO
BE ADVECTED INTO THE AREA FROM THE SOUTHEAST. UPPER LEVEL HIGH
PRESSURE TO THE NORTHWEST WILL SLOWLY EXPAND TO THE EAST ALLOWING
ADDITIONAL MOISTURE TO BE PULLED INTO THE REGION. ALSO...SOME
COOLING HAS TAKEN PLACE AT THE UPPER LEVELS RESULTING IN ADDITIONAL
CAPE. HOWEVER...AN ELEVATED INVERSION IN THE MID LEVELS WILL NEED TO
BE OVERCOME...WHICH SHOULD NOT BE A PROBLEM DUE TO THE CONVECTIVE
TEMPERATURE BEING 92. ONLY A DELAY TO THE CONVECTION COMPARED TO
YESTERDAY IS EXPECTED. THEREFORE...WITH THE MOISTURE REMAINING OVER
SOUTHERN ARIZONA THE BEST CHANCE OF HEAVY RAIN AND STRONG WINDS WILL
BE WITHIN THE SOUTHERN PORTION OF THE COUNTY WARNING AREA. THIS
WOULD INCLUDE SANTA CRUZ...SOUTHERN COCHISE AND SOUTHERN PIMA
COUNTIES. THE STORMS ARE EXPECTED TO MOVE GENERALLY TOWARD THE WEST
OR NORTHWEST.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

SEASONAL SCATTERED THUNDERSTORMS WITH THE NORMAL IMPLIED THREAT OF
HEAVY RAIN AND STRONG WINDS WILL CONTINUE THROUGH THE WEEK.

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

EVANS

In the hours before

Special weather statement, Jul 29, 4:20 PM MST, 5 hours 40 minutes before

AZZ029>034-300500-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TUCSON AZ
420 PM MST TUE JUL 29 2003

...SEVERE THUNDERSTORM WATCH NUMBER 815 UNTIL 1000 PM...

THE STORM PREDICTION CENTER HAS ISSUED SEVERE THUNDERSTORM WATCH
NUMBER 815 FOR MOST OF SOUTHERN ARIZONA UNTIL 1000 PM MST. THIS
INCLUDES THE FOLLOWING COUNTIES...

PIMA...PINAL...GRAHAM...AND SANTA CRUZ

THUNDERSTORMS CAPABLE OF PRODUCING WIND GUSTS OVER 60 MPH...LARGE
HAIL...AND VERY HEAVY RAIN ARE POSSIBLE ACROSS MOST OF SOUTHERN
ARIZONA THIS EVENING. PAY CLOSE ATTENTION TO LOCAL MEDIA OUTLETS FOR
ADDITIONAL STATEMENTS AND POSSIBLE WARNINGS.

PYTLAK

Local storm report, Jul 29, 5:19 PM MST, 4 hours 41 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
0519 PM MST TUE JUL 29 2003

TIME(MST)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0250 PM    FT. HUACHUCA              AZ   85 MPH TSTORM WIND
07/29/03   COCHISE                        MEASURED AT LIBBY FIELD

0338 PM    SONOITA                   AZ   0.75 IN HAIL
07/29/03   SANTA CRUZ                     REPORTED BY SPOTTER

0420 PM    TUCSON                    AZ   WIND DAMAGE
07/29/03   PIMA                           TREE DOWNED AT RITA RD.
                                          AND OLD VAIL RD.

0435 PM    TUCSON                    AZ   WIND DAMAGE
07/29/03   PIMA                           POWER LINES DOWNED AT
                                          GRANT RD. AND PARK AVE.

0506 PM    TUCSON                    AZ   FLASH FLOOD
07/29/03   PIMA                           STREET FLOODING IN SOUTH
                                          AND CENTRAL PARTS OF THE
                                          CITY.

ESP

Local storm report, Jul 29, 5:41 PM MST, 4 hours 19 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
0541 PM MST TUE JUL 29 2003

TIME(MST)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0455 PM    RYAN FIELD                AZ   65 MPH WIND GUST
07/29/03   PIMA

0529 PM    TUCSON                    AZ   FLASH FLOOD
07/29/03   PIMA                           HEAVY STREET FLOODING NEAR
                                          SWAN AND 29TH ST. 2 1/2
                                          FEET OF WATER IN AN ALLEY
                                          DITCH. REPORTED BY STORM
                                          SPOTTER.

PYTLAK

Local storm report, Jul 29, 5:41 PM MST, 4 hours 19 minutes before

PRELIMINARY LOCAL STORM REPORT...CORRECTED FORMAT
NATIONAL WEATHER SERVICE TUCSON AZ
0541 PM MST TUE JUL 29 2003

TIME(MST)  .....CITY LOCATION.....STATE   ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0455 PM    RYAN FIELD                AZ   65 MPH TSTORM WIND GUST
07/29/03   PIMA                           MEASURED AT RYAN FIELD

0529 PM    TUCSON                    AZ   FLASH FLOOD
07/29/03   PIMA                           HEAVY STREET FLOODING NEAR
                                          SWAN AND 29TH ST. 2 1/2
                                          FEET OF WATER IN AN ALLEY
                                          DITCH. REPORTED BY STORM
                                          SPOTTER.

PYTLAK

Special weather statement, Jul 29, 6:30 PM MST, 3 hours 30 minutes before

AZZ029>034-300500-

SPECIAL WEATHER STATEMENT...UPDATE
NATIONAL WEATHER SERVICE TUCSON AZ
630 PM MST TUE JUL 29 2003

UPDATED TO REMOVE GRAHAM...SANTA CRUZ AND EASTERN PIMA COUNTIES FROM
THE SEVERE THUNDERSTORM WATCH

...SEVERE THUNDERSTORM WATCH NUMBER 815 UNTIL 1000 PM...

SEVERE THUNDERSTORM WATCH NUMBER 815 CONTINUES IN EFFECT FOR
PORTIONS OF SOUTHERN ARIZONA UNTIL 1000 PM MST. THE PORTIONS OF THE
WATCH THAT ARE STILL IN EFFECT INCLUDE...

CENTRAL AND WESTERN PIMA COUNTY...AND SOUTHEAST PINAL COUNTY

THUNDERSTORMS CAPABLE OF PRODUCING WIND GUSTS OVER 60 MPH...LARGE
HAIL...AND VERY HEAVY RAIN ARE POSSIBLE OVER PORTIONS OF SOUTHERN
ARIZONA THIS EVENING. PAY CLOSE ATTENTION TO LOCAL MEDIA OUTLETS FOR
ADDITIONAL STATEMENTS AND POSSIBLE WARNINGS.

Special weather statement, Jul 29, 8:30 PM MST, 1 hour 30 minutes before

AZZ029-031-032-300400-

SPECIAL WEATHER STATEMENT...UPDATE
NATIONAL WEATHER SERVICE TUCSON AZ
830 PM MST TUE JUL 29 2003

UPDATED TO REMOVE THE REST OF SOUTHERN ARIZONA FROM THE SEVERE
THUNDERSTORM WATCH

SEVERE THUNDERSTORM WATCH NUMBER 815 CONTINUES IN EFFECT FOR
PORTIONS OF CENTRAL ARIZONA UNTIL 1000 PM MST. HOWEVER...ALL OF
SOUTHERN ARIZONA HAS NOW BEEN REMOVED FROM THE SEVERE THUNDERSTORM
WATCH. SOUTHEAST PINAL AND CENTRAL AND WESTERN PIMA COUNTIES HAVE
NOW BEEN REMOVED FROM THE SEVERE THUNDERSTORM WATCH.

AT 825 PM MST...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
STRONG THUNDERSTORMS WERE STILL OCCURRING OVER PORTIONS OF FAR
WESTERN PIMA COUNTY. HOWEVER...THE THREAT FOR SEVERE WEATHER HAD
DIMINISHED GREATLY. THEREFORE...THE REST OF SOUTHERN ARIZONA HAS
BEEN REMOVED FROM THE SEVERE THUNDERSTORM WATCH.

The radar

The Tucson radar (KEMX), 112 km away, was scanning. The volume nearest the first event began at 04:59 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Pima

When: July 29, 10:00 PM MST to 11:55 PM MST
Where: Pima County, 12 mi NW of Tucson
Reported by: TRAINED SPOTTER
Coordinates: 32.097, -111.790 (the zone’s center; the record gives no point)

What these are

Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Arizona in 2003 Every state in 2003 This day in weather history Warnings in Arizona, July 2003

Sources

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: 5330438.