Flash Flooding in Arizona, August 15, 2003

Name: Flash Flooding in Arizona, August 15, 2003
Start: 2003-08-15T20:10
End: 2003-08-15T22:30
Location: Arizona

August 15, 2003 · NWS FGZ · 2 events in 2 counties and zones

Water was flowing over several roads near the intersection of Coconino, Yavapai, and Mojave counties. Water was flowing over Route 66 and Route 18 in several places.

Where it happened

Every event with a place to put it; 2 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: 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 FGZ wrote it up.

Water was flowing over several roads near the intersection of Coconino, Yavapai, and Mojave counties. Water was flowing over Route 66 and Route 18 in several places. There was also two feet of water flowing over Nelson Road near the town of Nelson.

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 Flagstaff, AZ wrote its last area forecast discussion before the first event at Aug 15, 2:30 PM MST, 5 hours 40 minutes earlier.

Area forecast discussion, Aug 15, 2:30 PM MST, 5 hours 40 minutes before

NORTHERN ARIZONA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 PM MST FRI AUG 15 2003

.SYNOPSIS...A WEATHER DISTURBANCE WILL CONTINUE TO BRING WIDESPREAD
SHOWER AND THUNDERSTORM ACTIVITY TO THE REGION THROUGH SATURDAY. THE
WEATHER SYSTEM WILL WEAKEN BY SUNDAY BUT ENOUGH MOISTURE WILL REMAIN
FOR A CHANCE OF SHOWERS AND THUNDERSTORMS INTO NEXT WEEK.

.DISCUSSION...UPPER TROUGH WAS CENTERED OVER THE ARIZONA/NEW MEXICO
BORDER THIS AFTERNOON. THE TROUGH WILL MOVE SLOWLY TO THE NORTHWEST
OVERNIGHT KEEPING MUCH OF NORTHERN ARIZONA UNDER A NORTHEAST FLOW.
OVER NORTHEAST ARIZONA SOME DRY AIR HAS ADVECTED IN FROM COLORADO
AND NEW MEXICO AND SEEMS TO BEE PUTTING A LIMIT ON STORM ACTIVITY
FROM THE MOGOLLON RIM NORTHWARD. ALONG...SOUTH AND WEST OF THE
MOGOLLON RIM DEEPER MOISTURE STILL REMAINS AND STORMS THAT FORM ON
THE RIM STILL MAY MOVE SOUTHWEST INTO THIS DEEPER MOISTURE. AS A
RESULT...A FLASH FLOOD WATCH IS IN EFFECT UNTIL MIDNIGHT TONIGHT FOR
PORTIONS OF YAVAPAI...GILA AND COCONINO COUNTIES. FOR SATURDAY AND
SUNDAY THE UPPER LOW PARKS RIGHT OVER ARIZONA WITH A
DEEP...MOIST...COOL AIR MASS. EXPECT ROUNDS OF ISOLATED TO SCATTERED
THUNDERSTORMS EACH DAY WITH A MORE NORMAL DIURNAL TREND IN
PRECIPITATION.

IN THE EXTENDED...NOT CLEAR WHAT THE FLOW PATTERN WILL BE FOR MONDAY
AND INTO THE MIDDLE OF NEXT WEAK. FAIRLY CERTAIN ARIZONA WILL AVOID
A SIGNIFICANT DRY PUNCH FROM THE EASTERN PACIFIC. THE GFS IS SHOWING
VERY LITTLE DRYING THROUGH THE MIDDLE OF NEXT WEEK AND THINK THIS IS
REASONABLE. WILL GO WITH A STANDARD MONSOON FORECAST FOR THE
EXTENDED WITH A CHANCE OF SHOWERS AND THUNDERSTORMS EACH DAY.

.FGZ...FLASH FLOOD WATCH UNTIL MIDNIGHT FOR ZONES
       004>009-012-015-016-018-037-038

.CODED TEMPERATURES/POPS FOR SELECTED CITIES IN NORTHERN ARIZONA

CITY             TEMPERATURES LO/HI           PROBABILITY OF PRECIP
                 TON SAT   SUN     MON        TON SAT   SUN     MON
FLAGSTAFF        048/072 048/075 048/077      060 050 030 040 040 040
WINSLOW          058/085 059/087 058/089      050 040 020 030 020 030
PRESCOTT         058/080 058/086 059/087      060 050 020 040 020 040
PAGE             069/088 065/087 065/090      050 040 020 040 020 040
WINDOW ROCK      049/077 047/077 049/081      050 050 030 040 040 040
CANYON DE CHELLY 057/083 055/083 057/087      040 040 020 040 030 040
COTTONWOOD       066/091 066/097 067/098      050 050 020 040 020 040
GRAND CANYON     048/073 048/076 048/078      060 050 020 040 030 040
GREER            045/067 045/070 045/072      060 060 040 050 050 050
HEBER            050/077 050/080 050/082      060 050 030 040 040 040
JACOB LAKE       048/070 048/073 048/075      060 050 030 040 040 040
NAVAJO N.M.      054/077 052/077 054/081      050 040 030 040 040 040
PAYSON           059/084 059/090 060/091      050 040 030 040 020 040
SEDONA           064/088 064/094 065/095      060 050 020 040 020 040
SELIGMAN         057/083 057/089 058/090      050 040 020 040 030 040
SHOW LOW         056/077 056/080 056/082      060 050 030 040 040 040
ST. JOHNS        053/080 054/082 053/084      050 040 020 040 030 040
WUPATKI N.M.     059/087 060/089 059/091      050 040 020 030 020 030

Hazardous weather outlook, Aug 15, 9:53 AM MST, 10 hours 17 minutes before

AZZ004>018-037>040-160200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
700 AM MST FRI AUG 15 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR APACHE...COCONINO...NORTHERN
GILA...NAVAJO...AND YAVAPAI COUNTIES IN NORTHERN ARIZONA.

.DAY ONE...TODAY

...FLASH FLOOD WATCH UNTIL MIDNIGHT FRIDAY FOR YAVAPAI...NORTHWEST
GILA AND WESTERN COCONINO COUNTY...

DEEP MOISTURE IS LOCATED ALONG...SOUTH AND WEST OF THE MOGOLLON RIM.
LATER THIS AFTERNOON THUNDERSTORMS ARE EXPECTED TO FORM ALONG THE
MOGOLLON RIM AND MOVE TO THE SOUTHWEST INTO THE DEEPER MOISTURE. THE
RESULT WILL BE SCATTERED HEAVY RAIN PRODUCING
THUNDERSTORMS...ESPECIALLY OVER YAVAPAI COUNTY. LOCALLY UP TO TWO
INCHES OF RAINFALL CAN BE EXPECTED IN THE AREAS UNDER THE FLASH
FLOOD WATCH...MAINLY LATE THIS AFTERNOON AND THIS EVENING. ELSEWHERE
ACROSS NORTHERN ARIZONA...ONLY ISOLATED TO SCATTERED THUNDERSTORM.

.DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY

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.

DEFINITION OF HAZARDOUS WEATHER...A WEATHER EVENT POSING A THREAT
TO LIFE AND PROPERTY.

The radar

The Flagstaff radar (KFSX), 124 km away, was scanning. The volume nearest the first event began at 03:07 UTC.

Open the radar archive at this moment

Event by event

2 flash flood. Local standard time, as filed.

Flash Flood, Yavapai

When: August 15, 8:10 PM MST to 10:30 PM MST
Where: Yavapai County, Nelson
Reported by: LAW ENFORCEMENT
Coordinates: 34.600, -112.554 (the zone’s center; the record gives no point)

Flash Flood, Coconino

When: August 15, 8:10 PM MST to 10:30 PM MST
Where: Coconino County, West Portion
Reported by: LAW ENFORCEMENT
Coordinates: 35.839, -111.770 (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: 5374250, 5374251.