Flash Flood and Hail in Arizona, July 23, 2003

Name: Flash Flood and Hail in Arizona, July 23, 2003
Start: 2003-07-23T18:30
End: 2003-07-23T21:00
Location: Arizona

July 23, 2003 · NWS TWC · 2 events in 1 county or zone

A severe thunderstorm developed over Tubac during the evening, which produced large hail and flash flooding. 75 inch diameter in size hail at 630 pm MST.

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: $30,000
Crop damage: None recorded
Events: 2

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 developed over Tubac during the evening, which produced large hail and flash flooding. A spotter reported 1.75 inch diameter in size hail at 630 pm MST. This storm also produced 1.75 to 2.10 inches of precipitation in the Palo Parado Estates and Tubac Country Club respectively. Most washes experienced heavy flow rates based on high water marks. The Tubac was had 5 feet of water and the Puerto Canyon was over topped banks along East Frontier Road and Camino Esplendido. Camino Esplendido had 5.5-6.0 feet of water crossing the road with damage to three properties. One house had 2-3 inches of water in the garage, but had no substantial damage. Another home had considerable damage with the water inside the house.

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 23, 3:05 PM MST, 3 hours 25 minutes earlier.

Area forecast discussion, Jul 23, 3:05 PM MST, 3 hours 25 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
305 PM MST WED JUL 23 2003

.SYNOPSIS...HIGH PRESSURE CENTERED OVER NEVADA WILL SLOWLY MOVE
TOWARD THE FOUR CORNERS REGION BY FRIDAY. WEAK DISTURBANCES ROTATING
AROUND THE HIGH WILL PROVIDE SCATTERED AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS THROUGH FRIDAY. AN INCREASE IN SHOWERS AND
THUNDERSTORMS IS EXPECTED BY SUNDAY AS A STRONGER DISTURBANCE MOVES
TOWARD SOUTHEAST ARIZONA.

.DISCUSSION...KEMX WSR-88D DETECTED SCATTERED MOSTLY LESS THAN 40
DBZ ECHOES MAINLY NEAR THE ERN MOUNTAINS MOVING SLOWLY NWWD AT
2140Z. CELL E BENSON APPROACHED 60 KG/M2 WORTHY OF SEVERE TSTM
WARNING. VISIBLE SATELLITE IMAGERY INDICATED GENERALLY CLEAR SKIES
ACROSS WRN SECTIONS WITH CUMULIFORM CLOUDINESS OVER CENTRAL/ERN
LOCALES. DEWPOINTS WERE IN THE LOWER-MID 50S F ERN SECTIONS WHILE
REMAINING AROUND 60 F TUS VICINITY WWD. BELIEVE SHOWERS/TSTMS WILL
DEVELOP DURING THE NEXT FEW HOURS BUT WILL BE SLOW TO MOVE TOWARD
VALLEYS. BEST CHANCE PRECIP TUS VICINITY SHOULD BE AFTER 01-02Z OR
SUCH PER LATEST MESO-ETA/MM5 OUTPUT. WILL OPT FOR SCATTERED EVENING
SHOWERS/THUNDERSTORMS WITH EXPECTATION OF ACTIVITY WANING EARLY ERN
SECTIONS THOUGH PERHAPS LINGERING ACROSS CENTRAL LOCALES. ONLY
ISOLATED EVENING THUNDERSTORMS EXPECTED ZONES 31/32. 23/12Z NWP
MODELS WERE WELL INITIALIZED PER PMDHMD. ETA/GFS CONCUR THAT AN
INCREASE IN CONVECTIVE DEVELOPMENT TO OCCUR THUR AFTERNOON/NIGHT AS
DEPICTED BY H5-H3 OMEGA/DIVERGENCE/TOTAL DEFORMATION FIELDS. THUS
WILL TREND POPS UPWARD MAINLY THUR EVENING TO REFLECT THIS SCENARIO.
UPPER HIGH TO MOVE TOWARD SRN CO BY SAT. AVN DEPICTS INVERTED TROF
TO ROTATE AROUND SE PERIPHERY OF HIGH ACROSS TX SAT AND TOWARD SE AZ
BY SUN. PER COORD WITH WFO/S PSR/FGZ WILL ADJUST POPS UPWARD SUN AND
TREND DOWNWARD SLIGHTLY MON AS SYSTEM MOVES WWD. LOW CONFIDENCE WITH
REGARD TO GFS/MRF TUE-WED SOLUTION PERTAINING TO SWRN CONUS/NRN BAJA
TROF. SO WILL MAINTAIN GENERIC POP SCENARIO FOR THE MOMENT. WILL
TREND DAYTIME MAX TEMPS DOWNWARD STARTING FRI WITH EXPECTATION THAT
SUN WILL BE COOLEST DAY GIVEN PROGGED PRECIPITATION.  BF

.TWC...NONE.

Hazardous weather outlook, Jul 23, 12:30 PM MST, 6 hours before

AZZ019-029>035-241400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1230 PM MST WED JUL 23 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...THUNDERSTORMS LAST NIGHT COOLED THE LOWER LAYERS OF THE
ATMOSPHERE WHICH GENERALLY LEADS TO LESS ACTIVITY ON THE FOLLOWING
DAY. THIS SHOULD CONFINE THE THUNDERSTORM ACTIVITY TO MAINLY THE
MOUNTAINS THIS AFTERNOON WITH THUNDERSTORMS MOVING INTO THE VALLEYS
THIS EVENING. NUMERICAL MODELS DO NOT INDICATE SIGNIFICANT ORGANIZED
CONVECTION TODAY...ALTHOUGH STORMS WILL PRODUCE LOCALLY HEAVY RAIN
DUE TO THE HIGH MOISTURE CONTENT OF THE ATMOSPHERE.

.DISCUSSION...TUCSON SOUNDING SIMILAR TO YESTERDAY ALTHOUGH LOW
LEVELS COOLED SOMEWHAT...ESPECIALLY PHOENIX SOUNDING WHICH DOES NOT
APPEAR ABLE TO SUPPORT SURFACED BASED STORMS. THE ONLY FACTOR THAT
MAY PUSH STORMS OFF THE MOUNTAINS IS FAIRLY STRONG MID LEVEL WINDS
OF 20 KNOTS OR SO. FIRST STORMS WILL DEVELOP...RAIN...AND MOVE OFF
MOUNTAINS AND THEN DISSIPATE AFTER THEY MOVE INTO VALLEYS. BY
EVENING...STORMS SHOULD BE ABLE TO MOVE INTO VALLEYS. AT THIS TIME
IT DOES NOT LOOK LIKE STORMS WILL PUSH MUCH FARTHER OUT IN THE
DESERTS THAN MARANA...BUT THE TUCSON VALLEY AS WELL AS THE I-19
CORRIDOR SEEM TO HAVE THE BEST POTENTIAL FOR THE HEAVIEST RAINS.

STORM MOTION WILL BE TO THE WEST TO NORTHWEST AT 15 MPH.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH WEDNESDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

SUFFICIENT MOISTURE WILL BE IN PLACE FOR A STANDARD SUMMERTIME
THUNDERSTORM SEASON FORECAST. EXPECT 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.

In the hours before

Local storm report, Jul 23, 5:21 PM MST, 1 hour 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE TUCSON AZ
0521 PM MST WED JUL 23 2003

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

0430 PM    ORACLE                    AZ   0.75 IN HAIL
07/23/03   PINAL

VPH

The radar

The Tucson radar (KEMX), 50 km away, was scanning. The volume nearest the first event began at 01:27 UTC.

Open the radar archive at this moment

Event by event

1 hail, 1 flash flood. Local standard time, as filed.

Hail, Santa Cruz

When: July 23, 6:30 PM MST to 6:35 PM MST
Where: Santa Cruz County, Tubac
Measured: 1.75 in hail
Property damage: $30,000
Reported by: TRAINED SPOTTER
Coordinates: 31.617, -111.050

Flash Flood, Santa Cruz

When: July 23, 7:00 PM MST to 9:00 PM MST
Where: Santa Cruz County, Tubac
Reported by: TRAINED SPOTTER
Coordinates: 31.526, -110.847 (the zone’s center; the record gives no point)

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
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: 5330162, 5330163.