A trough of low pressure over Arizona led to the development of some showers and thunderstorms. A few short wave troughs embedded in the mean flow provided the dynamics necessary for gusty winds and small hail associated with the thunderstorms.
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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.
The episode as NWS TWC wrote it up.
A trough of low pressure over Arizona led to the development of some showers and thunderstorms. A few short wave troughs embedded in the mean flow provided the dynamics necessary for gusty winds and small hail associated with the thunderstorms.
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 Apr 10, 2:45 PM MST, 3 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 245 PM MST SAT APR 10 2004 SOUTHEAST ARIZONA FORECAST DISCUSSION .SYNOPSIS...A SERIES OF DISTURBANCES WILL MOVE ACROSS ARIZONA TONIGHT AND SUNDAY...BRINGING ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS TO SOUTHERN ARIZONA. A RATHER VIGOROUS DISTURBANCE WILL MOVE ACROSS SOUTHERN ARIZONA TONIGHT BRINGING THE THREAT OF SEVERE WEATHER THROUGH THE EARLY EVENING HOURS. A WEAKER DISTURBANCE WILL MOVE ALONG THE NEW MEXICO BORDER ON SUNDAY BRINGING THE CONTINUED CHANCE OF SHOWERS AND STORMS. DRY AND WARMER WEATHER IS THEN EXPECTED NEXT WEEK AS A RIDGE OF HIGH PRESSURE BUILDS OVER THE REGION. ANOTHER STORM SYSTEM IS FORECASTED TO MOVE INTO THE DESERT SOUTHWEST LATE IN THE WEEK...BRINGING INCREASING CLOUDS AND A LITTLE COOLER TEMPERATURES. && .DISCUSSION...KEMX RADAR INDICATES SHOWERS AND STRONG STORMS OVER EASTERN PORTIONS SOUTHEAST ARIZONA ATTM. SPC ISSUED A SEVERE THUNDERSTORM WATCH (NUMBER 62) FOR EASTERN PORTIONS OF SOUTHEAST ARIZONA THROUGH 6 PM MST. THE COMBINATION OF FAIRLY IMPRESSIVE LAPSE RATES...DAYTIME HEATING AND A STRONG VORT MAX CENTERED OVER WEST CENTRAL ARIZONA WILL LEAD TO THE CONTINUED THREAT OF SEVERE WEATHER THROUGH THE LATE AFTERNOON AND EARLY EVENING HOURS. SURFACE DEWPOINTS HAVE CONTINUED TO RISE ACROSS SOUTHERN ARIZONA DURING THE AFTERNOON HOURS AND ARE CURRENTLY IN THE 40S TO LOWER 50S. WITH SUFFICIENT MOISTURE IN PLACE AND INCREASING DYNAMICS/SYNOPTIC SCALE FORCING EXPECTED TO MOVE INTO THE AREA TONIGHT...THE CHANCE OF SHOWERS AND STORMS WILL CONTINUE THROUGH THE OVERNIGHT HOURS TONIGHT ACROSS THE EASTERN TWO-THIRDS OF THE FORECAST AREA. A WEAKER IMPULSE WILL DIVE SOUTH ALONG THE NEW MEXICO BORDER ON SUNDAY...ROTATING EAST OF THE STATE SUNDAY EVENING. THIS WILL CONTINUE THE CHANCE OF SHOWERS AND STORMS MAINLY FAR EASTERN PORTIONS OF THE FORECAST AREA...IN GREENLEE...COCHISE AND GRAHAM COUNTIES. DRY AND WARMER CONDITIONS ARE THEN EXPECTED THROUGH MUCH OF NEXT WEEK AS A RIDGE OF HIGH PRESSURE BUILDS IN FROM THE WEST AND TRANSITIONS ACROSS THE DESERT SOUTHWEST DURING THE WEEK. A DEGREE OR TWO OF COOLING IS EXPECTED MID WEEK AS A SYSTEM MOVES ACROSS THE GREAT BASIN AND HEIGHTS FALL SLIGHTLY. A STRONGER STORM SYSTEM WILL THEN MOVE INTO THE REGION LATE IN THE WEEK...FOR INCREASING CLOUDS AND COOLER TEMPERATURES...ALONG WITH A SLIGHT CHANCE OF SHOWERS IN THE WHITE MOUNTAINS. && .FIRE WEATHER...A TROUGH WILL BRING SCATTERED STRONG THUNDERSTORMS THIS EVENING...WITH THUNDERSTORMS DECREASING IN COVERAGE AND INTENSITY TOWARD DAYBREAK SUNDAY. THE TROUGH WILL MOVE TO THE EAST ON SUNDAY WITH ONLY ISOLATED THUNDERSTORMS EXPECTED ACROSS NORTHERN GREENLEE...GRAHAM AND COCHISE COUNTIES. A RIDGE WILL THEN BUILD IN STARTING MONDAY...PROVIDING DRY WEATHER AREAWIDE THROUGH FRIDAY. A DIURNAL WIND REGIME WILL ALSO PREVAIL ALONG WITH GRADUALLY DECREASED HUMIDITIES DURING THE AFTERNOONS. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE TUCSON AZ 600 PM MST SAT APR 10 2004 AZZ019-029>035-111400- NORTHERN GREENLEE COUNTY-SOUTHEAST PINAL COUNTY- UPPER GILA RIVER VALLEY-WESTERN PIMA COUNTY- TOHONO OODHAM NATION-TUCSON METRO/MARANA/GREEN VALLEY- SANTA CRUZ COUNTY-COCHISE COUNTY- 600 PM MST SAT APR 10 2004 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST ARIZONA .DAY ONE...TODAY ...SEVERE THUNDERSTORM WATCH EXPIRED AT 6 PM MST... THE THREAT OF SEVERE THUNDERSTORMS HAD DIMINISHED ACROSS THE AREA EARLY THIS EVENING. THUS...THE WATCH WAS ALLOWED TO EXPIRE AT 6 PM MST. HOWEVER...SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUED THROUGH ABOUT MIDNIGHT BEFORE BECOMING MORE ISOLATED OVERNIGHT. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE TUCSON AZ 112 PM MST SAT APR 10 2004 AZZ019-029>030-033>035-110100- NORTHERN GREENLEE COUNTY-SOUTHEAST PINAL COUNTY-UPPER GILA RIVER VALLEY-TUCSON METRO/MARANA/GREEN VALLEY-SANTA CRUZ COUNTY-COCHISE COUNTY- 112 PM MST SAT APR 10 2004 ...SEVERE THUNDERSTORM WATCH NUMBER 62 IN EFFECT UNTIL 6 PM MST... THE STORM PREDICTION CENTER HAS ISSUED A SEVERE THUNDERSTORM WATCH FOR PORTIONS OF SOUTHERN AND EASTERN ARIZONA UNTIL 6 PM MST. HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING WILL BE POSSIBLE. IN SOUTHERN ARIZONA THE SEVERE THUNDERSTORM WATCH INCLUDES THE FOLLOWING COUNTIES...COCHISE...GRAHAM...GREENLEE...SOUTHEAST PINAL...SANTA CRUZ AND EASTERN PIMA. SOME CITIES INCLUDED IN THE WATCH ARE...TUCSON...GREEN VALLEY...ELOY...ORACLE...NOGALES... SAFFORD...CLIFTON...HANNAGAN MEADOW...WILLCOX...BENSON...SIERRA VISTA...AND DOUGLAS. REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY DO PRODUCE TORNADOES. ZELL
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE TUCSON AZ 600 PM MST SAT APR 10 2004 AZZ019-029>030-033>035-110115- NORTHERN GREENLEE COUNTY-SOUTHEAST PINAL COUNTY-UPPER GILA RIVER VALLEY-TUCSON METRO/MARANA/GREEN VALLEY-SANTA CRUZ COUNTY-COCHISE COUNTY- 600 PM MST SAT APR 10 2004 ...SEVERE THUNDERSTORM WATCH NUMBER 62 EXPIRED AT 6 PM MST... THE SEVERE THUNDERSTORM WATCH THAT WAS POSTED FOR PARTS OF SOUTHEAST ARIZONA EARLIER THIS AFTERNOON EXPIRED AT 6 PM MST. ALTHOUGH THE THREAT OF SEVERE WEATHER HAD DIMINISHED...SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL CONTINUE OVER SOUTHEAST ARIZONA THIS EVENING. THE AREAL COVERAGE OF SHOWERS WILL BECOME MORE ISOLATED AFTER MIDNIGHT TONIGHT.
The Tucson radar (KEMX), 134 km away, was scanning. The volume nearest the first event began at 01:16 UTC.
1 thunderstorm wind. Local standard time, as filed.
An isolated thunderstorm moving east produced a 56 mph wind gust and knocked down a power pole in Safford. Also the Safford Agricultural Station reported wind gusts up to 57 mph.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2004Every state in 2004This day in weather historyWarnings in Arizona, April 2004
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: 5390312.