Moisture associated with Tropical Depression 19E caused widespread rain and thunderstorms over southeast Arizona during the afternoon and evening. The result was flash flooding in Picture Rocks, Sahuarita, Corona De Tucson and Thatcher.
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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.
Moisture associated with Tropical Depression 19E caused widespread rain and thunderstorms over southeast Arizona during the afternoon and evening. The result was flash flooding in Picture Rocks, Sahuarita, Corona De Tucson and Thatcher. In addition, a person walking in the Pantano Wash was overcome by rising water levels and needed to be rescued.
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 Sep 19, 3:50 PM MST, 10 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 350 PM MST Wed Sep 19 2018 .SYNOPSIS...Numerous showers with embedded thunderstorms decreasing in coverage especially west of Tucson tonight. Scattered showers and thunderstorms Thursday mainly east of Tucson. A few thunderstorms Friday generally southeast to south of Tucson, then dry conditions Saturday into next Wednesday. A warming trend will also occur Thursday into early next week. && .DISCUSSION...Widespread showers with embedded thunderstorms were occurring across southeast Arizona at this time. The bulk of heavier rainfall as per radar imagery extended from Santa Cruz County northward across the Tucson metro area, and further northward into Pinal County. Expect numerous showers with scattered thunderstorms this evening. Various HRRR solutions suggest that showers will mostly end across western sections by midnight, but scattered showers and thunderstorms should continue late tonight from Tucson eastward to the New Mexico state line. The official forecast generally follows this scenario, although have maintained chance- category PoPs west of Tucson late tonight. The Flash Flood Watch should be allowed to expire at 11 pm MST. Upper level trough axis that extends from the Pacific Northwest southward into southern California will move eastward into southeast Arizona Thursday morning. This upper trough axis is progged to move eastward into the southern Rockies Thursday afternoon. As the mid/ upper flow becomes increasingly nly/nwly behind this trough axis, a drying trend will ensue. Thus, isolated to scattered showers/tstms Thursday afternoon mainly east of Tucson with precip-free conditions across western Pima County. Isolated showers/tstms to continue Thursday night east of Tucson with dry conditions elsewhere. The 19/12Z GFS/ECMWF were similar with depicting high pressure aloft to build over the southwestern CONUS Friday. Have noted that the ECMWF depicted light rainfall amounts to occur near the International border south of Tucson Friday afternoon. However, the GFS depicted dry conditions. There may be enough residual moisture to justify isolated showers/tstms Friday into Friday night southeast to south of Tucson. The official forecast depicts this scenario even though forecast confidence is low in this regard. Thereafter, the GFS/ECMWF were fairly similar with depicting an amplifying upper high near the Pacific Northwest coast early next week, and generally nwly/nly flow across southeast Arizona. However, the ECMWF was definitely more robust with precip chances especially by next Wednesday versus the GFS. A generally nwly/nly flow aloft regime would more support the drier GFS versus the ECMWF. At any rate, have opted for precip-free conditions for this forecast issuance Saturday into next Wednesday. A warming trend will occur for much of the area Thursday, with the most noticeable warming from Tucson westward. Safford may actually cool a couple of degrees Thursday versus this afternoon. Warmer temps are on tap area-wide Friday into this weekend, then no significant daily high temp changes are forecast to occur Monday into Wednesday. && .AVIATION...Valid through 21/00Z. Numerous TSRA/SHRA this evening then scattered -TSRA/-SHRA mainly KTUS vicinity late tonight and continuing into Thursday afternoon. Expect MVFR conditions and brief IFR conditions at times through valid period. Otherwise, cloud decks generally 5k-10k ft AGL. Surface wind variable in direction mainly less than 12 kts except gusts near 30 kts with stronger TSRA. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Widespread showers with embedded thunderstorms gradually decreasing in coverage tonight, particularly west of Tucson. Scattered thunderstorms Thursday especially east of Tucson followed by isolated thunderstorms Friday mainly southeast east to south of Tucson. Dry conditions to occur across much of the area Saturday into next Wednesday. 20-foot winds will be terrain driven mainly less than 15 mph during much of this forecast period. However, occasionally gusty east winds may occur this weekend. && .TWC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until 11 PM MST this evening for AZZ501>515. && Francis Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
The Tucson radar (KEMX), 6 km away, was scanning. The volume nearest the first event began at 22:57 UTC.
3 flash flood. Local standard time, as filed.
Heavy rain of 1 to 3 inches fell along and south of Sahuarita Road during the afternoon, causing washes to flow over Sahuarita Road up to two feet deep. Several motorists were stranded in flood waters.
Tucker Rd at Blanca Wash was impassable with 3 feet of water running over the road.
During the late afternoon and evening 1.5-2.5 inches caused flash flooding in Thatcher. Two homes flooded and roads were flooded in Quail Ridge as the drainage canal overflowed. Farther north, several of the dorm rooms at the Eastern Arizona College|Campus, several of the Howards Place apartments on High School Avenue also suffered flood damage.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2018Every state in 2018This day in weather historyWarnings in Arizona, September 2018
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: 787151, 786109, 786110.