Flash Flood in Arizona, August 25, 2003

Name: Flash Flood in Arizona, August 25, 2003
Start: 2003-08-25T21:30
End: 2003-08-25T23:00
Location: Arizona

August 25, 2003 · NWS TWC · 1 event in 1 county or zone

5 foot rise in the Canada del Oro Wash. The rise in water closed several roads along the Canada del Oro Wash that included Overton Rd and La Cholla Blvd.

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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Wind
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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.

Thunderstorms earlier in the evening produced heavy rain that caused a 12.5 foot rise in the Canada del Oro Wash. The rise in water closed several roads along the Canada del Oro Wash that included Overton Rd and La Cholla Blvd. Heavy rain also fell over northeast portions of the city along the Agua Cliente Wash, which also caused several road closures.

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 25, 9:30 PM MST, 0 minutes earlier.

Area forecast discussion, Aug 25, 9:30 PM MST, 0 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
930 PM MST MON AUG 25 2003

.SYNOPSIS...INCREASING MOISTURE ASSOCIATED WITH HURRICANE IGNACIO
WILL TRACK NORTH TOWARD THE DESERT SOUTHWEST EARLY THIS WEEK. THIS
INFLUX IN MOISTURE SHOULD LEAD TO AN UPSWING IN RAINFALL
COVERAGE...ESPECIALLY LATE TUESDAY AND WEDNESDAY.

.DISCUSSION...ANOTHER ROUND OF STRONG SCATTERED CONVECTION
PERSISTING WELL INTO THE EVENING HOURS. STILL HAVE INVERTED TROUGH
STALLED TO OUR EAST HELPING TO ENHANCE STORMS. LARGE SCALE HIGH
CENTER TO OUR NORTHEAST WITH PLENTY OF MOISTURE AND INSTABILITY
OTHERWISE.

IGNACIO HAS MADE LANDFALL ACROSS THE SOUTHERN BAJA PENINSULA WITH
THE OFFICIAL TRACK BRINGING IT VERY SLOWLY UP THE PENINSULA AS IT
WEAKENS OVER THE NEXT SEVERAL DAYS. MOISTURE PUSHED UP THE GULF FROM
THE NORTHEAST QUADRANT OF THE STORM AS WELL AS MOISTURE DRAWN INTO
THE INVERTED TROUGH POSITION SHOULD ENHANCE CONVECTION THE NEXT
COUPLE OF DAYS. BEST TIME FOR MOISTURE AND DYNAMICS COMING TOGETHER
FOR SOUTHEAST ARIZONA APPEARS TO BE WHEN THE INVERTED TROUGH AXIS
SHIFTS CLOSER...FROM ABOUT TUESDAY 18Z TO THURSDAY 06Z. UPSWING OF
STORM COVERAGE FOR THAT PERIOD IN THE FORECAST AND HEAVIER QPF AS
WELL. CURRENT FORECAST HAS THE RIGHT TRENDS. M

.TWC...NONE.

Hazardous weather outlook, Aug 25, 11:10 AM MST, 10 hours 20 minutes before

AZZ019-029>035-261400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1110 AM MST MON AUG 25 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY

SYNOPSIS...AS AN UPPER LEVEL INVERTED TROUGH OVER THE TEXAS BIG BEND
CONTINUES TO MOVE VERY SLOWLY TO THE WEST...EXPECT ANOTHER ROUND OF
SCATTERED SHOWERS AND THUNDERSTORMS AS THE ATMOSPHERE REMAINS MOIST
AND UNSTABLE. AS HAS BEEN THE CASE SINCE SATURDAY...THE MAIN THREAT
FROM THE STORMS THAT DEVELOP THIS AFTERNOON AND EVENING WILL BE
HEAVY RAIN THAT MAY LEAD TO FLASH FLOODING. THERE IS A MINIMAL RISK
FOR SEVERE WEATHER ACROSS THE AREA. FOR MORE DETAILS CHECK FOR AN
UPDATE OF THIS OUTLOOK AROUND NOON.

DISCUSSION...STILL LOOKING AT A SIMILAR WEATHER PATTERN AGAIN TODAY
WITH A LOW PRESSURE SYSTEM AND ASSOCIATED INVERTED TROUGH TO OUR
EAST AND THE MOISTURE AXIS RUNNING RIGHT THROUGH AZ. MORNING UPPER
AIR SOUNDINGS SHOWED HIGH PWATER VALUES AND MODERATE INSTABILITY
OVER THE AREA FOR TODAY. DAYTIME SURFACE HEATING AND SOME WEAK UPPER
LEVEL SUPPORT FROM THE TROUGH TO OUR EAST WILL AID IN THE
DEVELOPMENT OF STORMS THIS AFTERNOON AND EVENING. THE MAIN THREAT
FROM THESE STORMS WILL BE FLASH FLOODING...ALTHOUGH DAMAGING WINDS
COULD ACCOMPANY SOME OF THE STRONGER STORMS.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

MOISTURE FROM HURRICANE IGNACIO...WHICH WILL MOVE NORTH UP THE GULF
OF CALIFORNIA THIS WEEK...WILL KEEP A VERY MOIST ATMOSPHERE IN PLACE
ACROSS SOUTHEAST ARIZONA. SCATTERED SHOWERS AND THUNDERSTORMS WILL
DEVELOP TUESDAY AND WEDNESDAY WITH THE MAIN THREATS BEING HEAVY
RAINS THAT MAY LEAD TO FLASH FLOODING. A DRIER SOUTHWEST FLOW ALOFT
WILL DEVELOP ACROSS THE DESERT SOUTHWEST LATER IN THE WORK WEEK AND
INTO THE WEEKEND.

.SPOTTER INFORMATION STATEMENT...

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

The radar

The Tucson radar (KEMX), 112 km away, was scanning. The volume nearest the first event began at 04:32 UTC.

Open the radar archive at this moment

Event by event

1 flash flood. Local standard time, as filed.

Flash Flood, Pima

When: August 25, 9:30 PM MST to 11:00 PM MST
Where: Pima County, Tucson
Reported by: EMERGENCY MANAGER
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: 5377140.