Flash Flood and Hail in Arizona, July 12, 2003

Name: Flash Flood and Hail in Arizona, July 12, 2003
Start: 2003-07-12T19:00
End: 2003-07-12T21:30
Location: Arizona

July 12, 2003 · NWS TWC · 3 events in 1 county or zone

Scattered thunderstorms developed over the White Mountains early in the afternoon. Outflow from these thunderstorms helped initiate convection over the Catalina and Rincon Mountains, on the north and east side of Tucson.

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: $5,000
Crop damage: None recorded
Events: 3

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.

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 12, 2:45 PM MST, 4 hours 15 minutes earlier.

Area forecast discussion, Jul 12, 2:45 PM MST, 4 hours 15 minutes before

SOUTHEAST ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TUCSON AZ
245 PM MST SAT JUL 12 2003

.SYNOPSIS...STRONG HIGH PRESSURE HAS DEVELOPED AN EASTERLY FLOW
ACROSS THE AREA. MOISTURE OVER THE STATE WILL GENERATE AFTERNOON AND
EVENING THUNDERSTORMS AGAIN TODAY...BUT NOT AS NUMEROUS AS FRIDAY.
SLIGHTLY DRIER WEATHER ON SUNDAY WILL RESULT IN A DECREASE IN
THUNDERSTORM ACTIVITY AS THE HIGH PRESSURE CENTER EXPANDS OVER THE
REGION AND SHIFTS TO THE SOUTHWEST.

.DISCUSSION...CURRENTLY RADARS ARE DETECTING ISOLATED SHOWERS AND
THUNDERSTORMS DEVELOPING ALONG THE RIM COUNTRY OF GREENLEE COUNTY AS
ANTICIPATED. A FEW SHOWERS DEVELOPING SOUTH OF TUCSON...NEAR NOGALES
BUT NOT NEAR AS MANY AS THIS TIME YESTERDAY. SURFACE OBSERVATIONS
INDICATE THAT THE AIRMASS IS NOT AS UNSTABLE AS YESTERDAY WITH
DEWPOINTS GENERALLY LOWER BY 2 TO 5 DEGREES THAN THIS TIME YESTERDAY.

MODELS ARE IN GENERAL AGREEMENT IN TAKING THE 500MB HIGH OVER NORTH
CENTRAL ARIZONA TO A POSITION A LITTLE FARTHER SOUTH AND WEST DURING
THE DAY ON SUNDAY AND THIS CONTINUES THROUGH AT LEAST TUESDAY. MEAN
RH VALUES DECREASE AS A RESULT OF THIS CHANGE IN POSITION AND THUS
EXPECT SHOWERS AND THUNDERSTORM ACTIVITY TO DECREASE THROUGH
TUESDAY. BY WEDNESDAY THINGS BEGIN TO CHANGE AS THE UPPER HIGH
SHIFTS TO THE FOUR CORNERS REGION ALLOWING MOISTURE TO SPREAD ACROSS
ARIZONA FROM THE EAST WITH ISOLATED SHOWERS AND STORMS EXPECTED OVER
NORTHERN PORTIONS OF THE FORECAST AREA AND SCATTERED STORMS OVER THE
SOUTHEAST PORTIONS...AND THIS WILL CONTINUE INTO THE EARLY PART OF
THE WEEKEND.

AS THE HIGH SETTLES TO THE SOUTHWEST EXPECT TEMPS TO INCREASE ON
SUNDAY...BUT WITH THE HIGH MOVING BACK TO THE FOUR CORNERS REGION BY
MIDWEEK EXPECT AN INCREASE IN MOISTURE ALONG WITH HEIGHT FALLS AND
TEMPS WILL BE SEVERAL DEGREES LOWER TOWARD THE MIDDLE AND END OF THE
WEEK.

MOLLERE

.TWC...NONE.

Hazardous weather outlook, Jul 12, 12:00 PM MST, 7 hours before

AZZ019-029>035-131400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TUCSON AZ
1200 PM MST SAT JUL 12 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA

.DAY ONE...TODAY
THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

SYNOPSIS...MOISTURE OVER SOUTHEAST ARIZONA WILL GENERATE AFTERNOON
AND EVENING THUNDERSTORMS AGAIN TODAY.  ALTHOUGH STILL EXPECTING
SCATTERED THUNDERSTORMS IN COCHISE AND SANTA CRUZ
COUNTIES...THUNDERSTORMS WILL BE MORE ISOLATED COMPARED TO YESTERDAY
AS MOVE NORTHWARD AWAY FROM THE ARIZONA AND MEXICO BORDER. SOME
THUNDERSTORMS MAY BE SEVERE...PRODUCING WIND GUST IN EXCESS OF 60
MPH.  ALSO THE PROBABILITY OF PRECIPITATION EXCEEDING ONE INCH WILL
BE POSSIBLE WITH THE STRONGER STORMS...PRIMARILY AT HIGH ELEVATIONS.

DISCUSSION...THUNDERSTORMS SHOULD HAVE NO PROBLEM DEVELOPING LATER
THIS AFTERNOON SINCE MOISTURE IS NOT A LIMITING FACTOR. DEW POINT
TEMPERATURES ACROSS SOUTHEAST ARIZONA UP IN THE MID 50S TO 60S THIS
MORNING. ALTHOUGH THE PRECIPITABLE WATER VALUES FROM THE 12Z KTUS
SOUNDING DROPPED FROM 1.30 YESTERDAY MORNING TO 1.18...THERE STILL
ENOUGH TO HELP PRODUCE SOME AFTERNOON CONVECTION.  SCATTERED
THUNDERSTORMS CAN BE EXPECTED ALONG THE ARIZONA AND MEXICO BORDER IN
THE DEEPER MOISTURE SEEN FROM THE GOES TOTAL PRECIPITABLE WATER
VALUES. HOWEVER...DEVELOPMENT SHOULD BECOME MORE ISOLATED AS MOVE
FURTHER NORTH.  A FEW THUNDERSTORMS COULD ALSO BE SEVERE...WITH WIND
GUSTS EXCEEDING 60 MPH AND POSSIBLY PEA SIZE OR SMALLER HAIL IN THE
HIGHEST ELEVATIONS.  ALTHOUGH PRECIPITABLE WATER DECREASED
SLIGHTLY...THERE STILL IS ENOUGH MOISTURE ACROSS SOUTHEAST ARIZONA
TO PRODUCE PRECIPITATION GREATER THAN AN INCH AT THE HIGHEST
ELEVATIONS...ESPECIALLY NEAR THE DEEPER MOISTURE ALONG ARIZONA AND
MEXICO BORDER.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY.

THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW.

.SPOTTER INFORMATION STATEMENT...

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

The radar

The Tucson radar (KEMX), 47 km away, was scanning. The volume nearest the first event began at 01:59 UTC.

Open the radar archive at this moment

Event by event

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

Thunderstorm Wind, Pima

When: July 12, 7:00 PM MST to 7:30 PM MST
Where: Pima County, Tucson
Measured: 55 kt (63 mph) measured gust
Property damage: $5,000
Reported by: TRAINED SPOTTER
Coordinates: 32.233, -110.933

A severe thunderstorm produced damaging winds. A spotters reported an awning blown off an apartment building on 5th Street and Alvernon Road. Several large trees were also blown down on 22nd Street and Columbus Road. A spotter recorded 63 mph wind gust on Old Spanish Trail and Freeman Road. Interstate 10 was closed for four hours near Kolb Road due to downed power poles.

Hail, Pima

When: July 12, 7:05 PM MST to 7:10 PM MST
Where: Pima County, Tucson
Measured: 0.75 in hail
Reported by: TRAINED SPOTTER
Coordinates: 32.233, -110.933

Spotter reported 0.75 inch diameter in size hail near 22nd and Houghton Roads.

Flash Flood, Pima

When: July 12, 8:05 PM MST to 9:30 PM MST
Where: Pima County, Tucson
Reported by: TRAINED SPOTTER
Coordinates: 32.097, -111.790 (the zone’s center; the record gives no point)

Several washes were flooded at Broadway Blvd and Freeman Rd. Road closures due to flooding occurred at Wentworth and Tanque Verde Wash and Drexel and Mission Roads. A spotter reported 12-18 inches of water at Stone and 6th Streets. Rain gages across the city ranged from 0.04 to 0.52 inches.

What these are

Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
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: 5329903, 5329902, 5330145.