Flash Flood in Arizona, August 26, 2003

Name: Flash Flood in Arizona, August 26, 2003
Start: 2003-08-26T16:50
End: 2003-08-26T18:30
Location: Arizona

August 26, 2003 · NWS TWC · 1 event in 1 county or zone

A severe thunderstorm produced heavy rain while it moved west through Tucson. Automated gages recorded rainfall rates of half of an inch in 10 minutes.

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.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

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 severe thunderstorm produced heavy rain while it moved west through Tucson. Automated gages recorded rainfall rates of half of an inch in 10 minutes. Numerous streets were flooded in central Tucson. Sabino Creek rose three feet in 15 minutes and Alamo wash rose three feet in 20 minutes, which both flooded several roads.

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 Aug 26, 2:55 PM MST, 1 hour 55 minutes earlier.

Area forecast discussion, Aug 26, 2:55 PM MST, 1 hour 55 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
255 PM MST TUE AUG 26 2003

.SYNOPSIS...ABUNDANT MOISTURE WILL PROVIDE SCATTERED TO NUMEROUS
SHOWERS AND THUNDERSTORMS TONIGHT AND WEDNESDAY. LOCALLY HEAVY RAINS
WILL OCCUR WITH THE STRONGER STORMS. A GRADUAL DECREASE IN SHOWERS
AND THUNDESTORMS IS EXPECTED THURSDAY INTO THE WEEKEND.

.DISCUSSION...KEMX WSR-88D DETECTED SCATTERED-NUMEROUS MOSTLY LESS
THAN 50 DBZ ECHOES GENERALLY E OF A GLOBE-ORACLE-KOLS LINE AT 2145Z.
THE STRONGEST STORMS WERE MAINLY FROM THE RINCONS-HUACHUCA MTNS.
CELLS WERE MOVING W AROUND 10 KTS. VISIBLE SATELLITE IMAGERY
INDICATED GENERALLY CLEAR SKIES ACROSS CENTRAL/WRN PIMA/SE PINAL
COUNTIES WITH EXTENSIVE CUMULIFORM/CIRRIFORM CLOUDINESS ELSEWHERE.
VERY MOIST AIRMASS IN PLACE AS EVIDENCED IN 26/12Z TUS SOUNDING WITH
PRECIP WATER VALUE NEAR 1.60 INCH. GOES PRECIP WATER IMAGERY INDICATED
VALUES RANGING FROM 1.40 E - 1.90 INCH W. HAVE ALREADY ISSUED FLASH
FLOOD WATCH FOR TONIGHT THROUGH WED FROM TUS VICINITY WWD AS
EXPECTED HEAVY RAINS WILL EXACERBATE FLOODING FROM MON NIGHT STORMS.
ETA/GFS SIMILAR WITH REGARD TO GRADUAL DECREASE IN MOISTURE ACROSS
SE AZ BEGINNING THUR. THUS SCENARIO ACCEPTED SOMEWHAT THOUGH HAVE
SEEN SOME DIFFERENCES IN MODEL CONTINUITY. AT ANY RATE WILL CONTINUE
PREVIOUS FORECASTS OF MAINLY AFTERNOON AND EVENING THUNDERSTORMS
THUR-LABOR DAY. DAYTIME MAX TEMPS WED-THUR EXPECTED TO BE BELOW
SEASONAL NORMALS FOR LATE AUG WITH A GRADUAL WARMING TREND FRI-LABOR
DAY.  BF

.TWC...FLASH FLOOD WATCH ZONES 029>031-034>WRN 035 UNTIL 28/00Z.

Hazardous weather outlook, Aug 26, 12:10 PM MST, 4 hours 40 minutes before

AZZ019-029>035-271400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1210 PM MST TUE AUG 26 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...HIGH PRESSURE ALOFT CENTERED TO OUR NORTH WILL BRING AN
EASTERLY FLOW ALOFT TODAY AND THEN MORE OF A SOUTHERLY DIRECTION ON
WEDNESDAY AS THE HIGH BEGINS TO SHIFT EAST. THERE WILL ALSO BE AN
INCREASE IN MOISTURE INTO WEDNESDAY FROM THE REMNANTS TO HURRICANE
IGNACIO...WHICH IS EXPECTED TO MOVE SLOWLY NORTHWEST UP THE BAJA
COAST. IN ADDITION...AN UPPER LEVEL INVERTED TROUGH ACROSS FAR WEST
TEXAS AND NEW MEXICO WILL SHIFT WESTWARD INTO THE REGION TONIGHT AND
WEDNESDAY. THE COMBINATION OF THESE FACTORS WILL BRING INCREASING
CHANCES OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON...CONTINUING
THROUGH TONIGHT AND INTO WEDNESDAY. HEAVY RAIN WILL BE POSSIBLE
DURING THIS TIME FRAME. THUS...A FLASH FLOOD WATCH HAS BEEN ISSUED
FOR A GOOD PORTION OF SOUTHEAST ARIZONA...STARTING THIS AFTERNOON
AND CONTINUING THROUGH TONIGHT AND INTO WEDNESDAY.

DISCUSSION...MANY FACTORS ARE COMING TOGETHER TODAY/TONIGHT AND EVEN
INTO WEDNESDAY THAT IS EXPECTED TO BRING A SIGNIFICANT ROUND OF
SHOWERS AND THUNDERSTORMS TO MOST OF SOUTHEAST ARIZONA DURING THIS
TIME FRAME. ABUNDANT MOISTURE CONTINUES IN PLACE...WITH AREA RAOBS
AND GOES PWAT IMAGERY INDICATING 1.2 TO 2.1 INCHES OF PRECIPITABLE
WATER ACROSS THE FORECAST AREA. IN ADDITION...MORNING SOUNDINGS ALSO
INDICATE MODERATE INSTABILITY VALUES...WITH AN UNMODIFIED LIFTED
INDEX OF MINUS 4.5 AND A POSITIVE ENERGY VALUE OF 1941 J/KG. IN
ADDITION...THE REMNANTS OF HURRICANE IGNACIO NEAR THE SOUTHERN TIP
OF BAJA CONTINUES TO MOVE VERY SLOWLY TO THE NORTHWEST...WITH
COPIOUS AMOUNTS OF MOISTURE BEING PUSHED NORTH OVER MEXICO AND INTO
SOUTHERN ARIZONA. AN INVERTED TROUGH TO OUR EAST IS FORECASTED TO
MOVE WEST INTO ARIZONA TONIGHT AND WEDNESDAY...WITH STRETCHING AND
DEFORMATION IN THE UPPER WIND FIELDS AHEAD OF THIS FEATURE AIDING
STORM DEVELOPMENT.

THE COMBINATION OF THESE FACTORS IS EXPECTED TO BRING A SIGNIFICANT
ROUND OF SHOWERS AND THUNDERSTORMS THIS AFTERNOON/TONIGHT AND INTO
WEDNESDAY...WITH THE MAIN THREAT FOR HEAVY RAINS THAT MAY LEAD TO
FLASH FLOODING. THERE WILL ALSO BE A MINIMAL RISK FOR SEVERE WEATHER
ACROSS THE AREA MAINLY DURING THE AFTERNOON HOURS. THEREFORE...THE
CHANCE OF SEVERE THUNDERSTORMS WILL BE SLIGHTLY BELOW CLIMATOLOGY
TODAY AND TONIGHT. HOWEVER...THE CHANCE FOR GREATER THAN ONE INCH OF
RAINFALL TODAY AND TONIGHT WILL BE ABOVE CLIMATOLOGY...ESPECIALLY
WEST OF A LINE FROM SIERRA VISTA...TO WILLCOX...TO MAMMOTH...TO
WINKELMAN. THE MOVEMENT OF THE SHOWERS AND STORMS WILL BE TO THE
WEST AROUND 15 MPH.

A FLASH FLOOD WATCH IS IN EFFECT FROM 200 PM THIS AFTERNOON THROUGH
TONIGHT FOR THE FOLLOWING LOCATIONS...WESTERN COCHISE...SANTA
CRUZ...SOUTHEAST PINAL AND PIMA COUNTIES. THE WATCH INCLUDES THE
FOLLOWING CITIES...GREEN VALLEY...MARANA...NOGALES...ORO VALLEY...
SELLS...SIERRA VISTA...BISBEE...WILLCOX AND THE TUCSON METRO AREA

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY.

ON WEDNESDAY...MOISTURE FROM FORMER HURRICANE IGNACIO WILL CONTINUE
TO MOVE NORTH INTO THE REGION...KEEPING A VERY MOIST ATMOSPHERE IN
PLACE ACROSS SOUTHEAST ARIZONA. THE MAIN THREAT FROM THE STORMS THAT
DEVELOP ON WEDNESDAY WILL AGAIN BE HEAVY RAIN THAT MAY LEAD TO FLASH
FLOODING.

A FLASH FLOOD WATCH CONTINUES IN EFFECT WEDNESDAY FOR THE FOLLOWING
LOCATIONS...WESTERN COCHISE...SANTA CRUZ...SOUTHEAST PINAL AND PIMA
COUNTIES. THE WATCH INCLUDES THE FOLLOWING CITIES...GREEN VALLEY...
MARANA...NOGALES...ORO VALLEY...SELLS...SIERRA VISTA... BISBEE...
WILLCOX AND THE TUCSON METRO AREA

SCATTERED SHOWERS AND THUNDERSTORMS ARE STILL EXPECTED ACROSS
EASTERN PORTIONS OF SOUTHERN ARIZONA IN THE THURSDAY THROUGH MONDAY
TIME FRAME...WHILE SOME DRYING IS EXPECTED OVER FAR WESTERN PORTIONS
OF THE STATE OVER THE WEEKEND AS A DRIER SOUTHWEST FLOW ALOFT BEGINS
TO DEVELOP ALONG THE WEST COAST AND PUSH EASTWARD.

.SPOTTER INFORMATION STATEMENT...

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

FOR MORE INFORMATION...SEE THE LATEST WEATHER BULLETINS:
                                AWIPS ID        WMO ID
FLASH FLOOD WATCH               PHXFFATWC       WGUS65 KTWC

ZELL

In the hours before

Local storm report, Aug 26, 4:27 PM MST, 23 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
0427 PM MST TUE AUG 26 2003

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

0425 PM    TUCSON                    AZ   WIND DAMAGE
08/26/03   PIMA                           POWER LINE DOWNED ON
                                          VEHICLE AT FT. LOWELL PARK

PYTLAK

The radar

The Tucson radar (KEMX), 112 km away, was scanning. The volume nearest the first event began at 23:51 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Pima

When: August 26, 4:50 PM MST to 6:30 PM MST
Where: Pima County, 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, August 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: 5377142.