An upper level ridge was centered over the central United States, with weak southwest flow over Arizona. 5 of precipitable water.
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.
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.
An upper level ridge was centered over the central United States, with weak southwest flow over Arizona. The morning sounding was quite moist, with about 1.5 of precipitable water. A shallow layer of drier air intruded into the area with easterly surface winds. A few showers and thunderstorms formed, some of which produced strong outflows.
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 27, 8:52 AM MST, 4 hours 8 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE TUCSON AZ 852 AM MST TUE AUG 27 2013 .SYNOPSIS...SOME DRYING FROM THE EAST TODAY WILL LIMIT THUNDERSTORM COVERAGE IN MANY LOCATIONS. ADDITIONAL MOISTURE WILL PUSH UP FROM THE SOUTH STARTING WEDNESDAY...WITH OCCASIONAL IMPULSES IN THE SOUTHERLY FLOW BRINGING A GOOD CHANCE OF THUNDERSTORMS THE SECOND HALF OF THE WEEK. && .DISCUSSION...THIS MORNINGS KTWC UNMODIFIED SOUNDING A BIT MISLEADING WITH A PW OF 1.29 INCHES...A LIFTED INDEX OF MINUS 6 AND A CAPE OF AROUND 3000 J/KG. HOWEVER...THE ABUNDANT MOISTURE SEEN IN THE LOWEST 100MB OR SO IS NOT EXPECTED TO BE THERE BY THIS AFTERNOON AS DRIER DEWPOINTS ARE EXPECTED TO OCCUR TODAY. MODIFYING THE SOUNDING USING T=102;TD=55 YIELDS A SIMILAR PW...BUT A LIFTED INDEX OF MINUS 2 AND A CAPE OF AROUND 800-900 J/KG. THAT SAID...NIGHT SHIFT REDUCED POPS FOR TODAY TO ONLY THE ISOLATED CATEGORY FOR CENTRAL AND EASTERN ZONES WITH LOW END SCATTERED STORMS FOR WESTERN DESERTS...AS WELL AS ALL MOUNTAIN TOPS. AS OF 15Z (8 AM MST)...TEMPERATURES ACROSS THE REGION RANGED FROM THE LOWER 70S TO THE LOWER 80S WITH THE TUCSON INTL AIRPORT REPORTING A TEMP OF 76 DEGS AFTER A MORNING LOW OF 69 DEGS. THESE READINGS SEEM TO BE GENERALLY ON TRACK WITH AFTERNOON HIGHS...BUT WILL MONITOR FOR ANOTHER HOUR OR SO AND WILL MAKE SOME ADJUSTMENTS TO THE SHORT TERM HOURLY TEMP GRIDS TO REFLECT ONGOING TRENDS. FOR DETAILS REGARDING THE FORECAST BEYOND TODAY...PLEASE REFER TO THE PREVIOUS DISCUSSION BELOW. && .AVIATION...MOSTLY CLEAR SKIES THIS MORNING WITH A FEW CLOUDS ABOVE 10K FT AGL. CU REDEVELOPING LATE THIS MORNING AND INTO THIS AFTERNOON WITH ISOLD TSRA DEVELOPING AFTER 27/18Z. SURFACE WIND GENERALLY ELY/SELY 5-15 KTS. AVIATION DISCUSSION NOT UPDATED FOR TAF AMENDMENTS. && .FIRE WEATHER...A BRIEF DOWNTURN IN THUNDERSTORMS TODAY WITH LESS ABUNDANT MOISTURE. OTHERWISE...EXPECT SCATTERED SHOWERS AND THUNDERSTORMS TO PREVAIL INTO THIS WEEKEND. GUSTY AND ERRATIC WINDS WILL OCCUR WITH THE STRONGER THUNDERSTORMS...ESPECIALLY DURING THE AFTERNOON AND EVENING HOURS. && .PREVIOUS DISCUSSION...INVERTED TROUGH WILL PUSH INTO CHIHUAHUA AND SONORA TONIGHT AND INTO SOUTHEAST ARIZONA WEDNESDAY AFTERNOON...ALSO SHEPHERDING IN A LINK BACK TO A LONG FETCH OF DEEP MOISTURE FROM THE SOUTHEAST AND SOUTH. PERIODIC IMPULSES EMBEDDED IN THE FLOW WILL ALSO HELP TO ENHANCE STORM COVERAGE PERIODICALLY FROM WEDNESDAY AFTERNOON INTO FRIDAY FOR AN ACTIVE PATTERN. && .TWC WATCHES/WARNINGS/ADVISORIES...NONE. && VISIT US ON FACEBOOK...TWITTER...YOUTUBE...AND AT WEATHER.GOV/TUCSON
The national radar mosaic for the moment the first event began.
1 strong wind. Local standard time, as filed.
Strong outflow from a light rain shower collapsed part of a crudely supported porch attached to a house southwest of Pima, AZ. A nearby carport was undamaged.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2013Every state in 2013This day in weather historyWarnings in Arizona, August 2013
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: 475079.