Slow moving thunderstorms developed across Cochise, Graham and Greenlee counties during the afternoon. Heavy rain up to 2 inches per hour caused areas of flash flooding.
Every event with a place to put it. 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.
Slow moving thunderstorms developed across Cochise, Graham and Greenlee counties during the afternoon. Heavy rain up to 2 inches per hour caused areas of flash flooding.
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 18, 2:53 PM MST, 1 hour 37 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 253 PM MST Sun Jul 18 2021 .SYNOPSIS...Thunderstorms are expected through this evening, mainly east and south of Tucson. Thereafter expect daily chances of showers and thunderstorms through the work week. High temperatures will remain below normal into the foreseeable future. && .DISCUSSION...Convection east of Tucson developing a few hours earlier than most CAM solutions suggested and speaks to the level of instability we have. The storms are moving to the NW, however fairly slowly and the few we have had have produce in excess of two inches of rain in 1 to 1.5 hours. A few of them have shown a tendency to redevelop in the same area as well. The saturated soils were very evident after this morning which resulted in flooding in Santa Cruz county with only one inch of rain. We also had flow in the Pima, Finger Rock and Esperero canyons this morning from 1/2 to 1 inches of rain, so we are definitely primed in that respect. For this afternoon and evening, all the CAM solutions show significant storm development east and south of Tucson including areas that have received recent heavy rains. Looking at the HREF, it is indicating fairly high probabilities of local areas of greater than an inch (in 3hr) this evening (5-8 pm) focused over eastern Pima, Santa Cruz and Cochise county, peaking at 70% eastern Cochise. There is even a 10% chance of greater than 3 inches in much of that area. Then for the 03Z-06Z period (8-11pm) the focus shifts to Cochise county with >50% of an inch and ~10% greater than 3 inches and has an MCS look to it. Given that and the saturated conditions we opted to issue a Flash Flood Watch through Midnight tonight east and south of Tucson, including Mt Lemmon for the Bighorn fire scar. Now we will have to see how this plays out, but the potential is certainly there. Monday through the work week the upper level high remains near or north of the 4-corners area, a favorable location for activity with deep easterly flow and plenty of moisture. Therefore there will be daily rounds of convection through the week, primarily focused on the afternoon and evening hours and varying from day to day. That said, as we saw this morning convection will be possible at anytime day or night depending on smaller forcing mechanisms. PWs remain as high as they have been so showers and thunderstorms will continue to be efficient rain producers and with the moist soil conditions, local flooding will continue to be a concern. Late in the week into the weekend there is some indication that there could be a trough over the area which would serve as a focus for convection if it becomes reality. Too soon to count on that but either way, the wet and active monsoon season looks to continue through next weekend. && .AVIATION...Valid through 20/00Z. SCT-BKN clouds at 8k-12k ft MSL with BKN layers above til 19/07Z the clouds slowly diminishing. SCT-NMRS SHRA/TSRA developing and persisting through the evening hours mainly east and south of Tucson before diminishing late tonight. Wind gusts to 45 kts possible near any TSRA along with MVFR conditions and mountain obscurations due to heavy rain. Otherwise, SFC wind generally less than 12 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...A wet monsoon pattern will continue through the coming work week resulting in scattered showers and thunderstorms. The convection will be primarily during the afternoon and evening hours but will be possible at anytime of the day or night. Primary concerns outside of the typical gusty winds is potential flooding due to heavy rains. Afternoon temperatures will remain below normal through the coming week with higher than average humidity levels continuing. && .TWC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until midnight MST tonight for AZZ503-506>509- 511>514. && Public...Cerniglia Aviation...Cerniglia Fire Weather....Cerniglia Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Special Weather Statement National Weather Service Tucson AZ 410 PM MST Sun Jul 18 2021 AZZ508-512-182345- Chiricahua Mountains including Chiricahua National Monument-Eastern Cochise County Below 5000 Feet including Douglas/Willcox- 410 PM MST Sun Jul 18 2021 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN COCHISE COUNTY UNTIL 445 PM MST... At 410 PM MST, Doppler radar was tracking a strong thunderstorm 12 miles north of Chiricahua National Monument, or 17 miles west of Steins, moving north at 10 mph. Winds in excess of 40 mph and blowing dust will be possible with this storm. Locations impacted include... San Simon. LAT...LON 3215 10918 3213 10937 3233 10948 3235 10921 TIME...MOT...LOC 2310Z 162DEG 9KT 3219 10929 AH
The Tucson radar (KEMX), 179 km away, was scanning. The volume nearest the first event began at 23:28 UTC.
5 flash flood. Local standard time, as filed.
One to two inches of rain in less than an hour caused flash flooding in the Clifton-Morenci area. One school was damaged by floodwaters.
A considerable area of more than 2 of rain fell in less than 1 hour east of Haekel Rd. in southeast Graham County. A section of the roadway was washed out by floodwaters near the Artesia Rd turnoff.
One to two inches of rain in less than 1 hour in the Sunsites area caused flash flooding and the closure of Birch Rd. near Highway 191.
One to two inches of rain in less than 1 hour south of San Simon caused flash flooding of roadways and resulted in the closing of Coyote Song Rd.
One to two inches of rain in less than 1 hour north of Willcox caused flash flooding of roadways and the closure of Hardy Rd.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2021Every state in 2021This day in weather historyWarnings in Arizona, July 2021
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: 975888, 975889, 975890, 975891, 975892.