Scattered thunderstorms moved developed and moved west across southeast Arizona. Storms produced heavy rain from late morning into early afternoon causing flash flooding in parts of Santa Cruz, western Cochise, and southeast Pima counties.
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.
Scattered thunderstorms moved developed and moved west across southeast Arizona. Storms produced heavy rain from late morning into early afternoon causing flash flooding in parts of Santa Cruz, western Cochise, and southeast Pima counties.
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 3, 9:18 AM MST, 3 hours 42 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 918 AM MST Sat Jul 3 2021 .SYNOPSIS...Plenty of moisture this holiday weekend for a good chance of showers and thunderstorms. Strong winds and heavy rain are a concern. Some drying is expected early next week, with fewer storms by the middle of the week. As this happens, temperatures will climb a few degrees. && .DISCUSSION...Several ingredients were in place today to support locally heavy rainfall with some of the stronger thunderstorms that develop. A few of the higher resolution models point to Santa Cruz into central and western Pima counties as being the most active, but most of SE AZ will experience thunderstorms by the end of the day. Please refer to the previous discussion for more details. && .AVIATION...Valid through 04/18Z. SCT-BKN clouds 7k-10k ft MSL through the period with layers above at times. Expect another round of scattered SHRA/TSRA this afternoon and evening with the possibility of some storms overnight. The best chance for KTUS to see storms will be 03/2200Z through 030300Z. Some of the storms could result in brief MVFR conditions due to heavy rain, low CIGS/VIS. In the vicnity of thunderstorms wind gusts to 40 kts will be possible. Otherwise expect wind speeds 5-10 kts from variable directions. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Deep monsoonal moisture will remain across the area through the weekend allowing for scattered showers and thunderstorms. Next week moisture content begins to decrease a little leading to reduced coverage of storms. Expect isolated to scattered showers and thunderstorms mainly from central Pima County eastward starting Monday. Humidity levels will remain elevated through Monday with afternoon mins about 25-35% in the valleys and 45-55% in the mountains with very good overnight recoveries. After Monday min RH values are expected to drop by about 10 percent, but overnight recoveries will still be very good. General winds will be light through the week and following normal daily trends when not influenced by storms. The only exception is the Gila River Valley which could see elevated winds during the beginning of next week. Any thunderstorm from here forward, especially during the afternoon or early evening hours will have the potential to produce strong, gusty outflows. && .PREV DISCUSSION... /issued 554 AM MST Sat Jul 3 2021/ The 12Z KTWC sounding came in with precipitable water now up to 1.81 inches (in 28 monsoons I don't recall ever seeing quite this much moisture in the very first days of July). Solid relatively easily accessible convective potential. Effective and BRN shear half of yesterday's levels. Storms will tend to choke out early before reaching their full potential. The latest HRRR is suggesting a scenario where initial storm development is sluggish and spotty before some organization with developing outflows hitting things harder very late in the afternoon and evening. We are edging toward being too wet but outflow activity (with an easterly steering level) from areas that get more insolation will probably be enough to fire strong thunderstorms. A tough call but we will lean forward a little more with best period for the wettest storms between 4PM-8PM for metro Tucson. As mentioned yesterday morning, we are still looking at an inverted trough feature near the southeast border in weak easterlies as the high center shifts slowly northwestward from Texas. That feature will likely help organize thunderstorms again later today into tonight, with another strong day possible Sunday. If it wasn't for this feature I would worry that our late convection and debris cloud from Sonora storms would keep us worked over for a murky light to moderate shower day. We're already seeing some partial clearing trends this morning, and the complex in Sonora is weakening rapidly now. Outflows from that could generate additional cloud cover over the border by sunrise, so best guess is that we see isolated to scattered storms possible anywhere through the day, then the more organized complex and outflows later in the day and this evening. WPC has us in a slight risk area for excessive rainfall, and we considered a flash flood watch for today, but there are a lot of timing issues depending on when we clear and where we clear first for first storm development and subsequent outflows. If clearing trends are favorable and the morning sounding is another looker, then it might not be a bad idea for mid to late afternoon into the early evening. Ensembles are still consistently building the ridge northward back into the southern Great Basin with our mid level flow backing around to the northeast once again early next week. With less upstream moisture around the high, that will tend to dry things out a bit. Ensemble means suggest we drop PW toward the 1.10 to 1.35 range next Tuesday and Wednesday, with correspondingly lower thunderstorm coverage. With a bit less moisture and cloud cover, and the ridge strengthening just north of us that should bring several degrees of heating for the second half of the week. At this point it looks like below average storm coverage Wed-Fri next week. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Special Weather Statement National Weather Service Tucson AZ 1151 AM MST Sat Jul 3 2021 AZZ502>504-515-031945- Tohono O'odham Nation including Sells-Upper Santa Cruz River and Altar Valleys including Nogales-Baboquivari Mountains including Kitt Peak-Tucson Metro Area including Tucson/Green Valley/Marana/Vail- 1151 AM MST Sat Jul 3 2021 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL PIMA AND NORTHWESTERN SANTA CRUZ COUNTIES UNTIL 1245 PM MST... At 1151 AM MST, Doppler radar was tracking strong thunderstorms along a line extending from 6 miles southeast of Three Points to 8 miles northwest of Tubac. Movement was west at 10 mph. Half inch hail and wind gusts up to 50 mph will be possible with these storms. Locations impacted include... Three Points and San Pedro. PRECAUTIONARY/PREPAREDNESS ACTIONS... Heavy rainfall is also occurring with these storms, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 3214 11155 3162 11147 3166 11111 3205 11115 TIME...MOT...LOC 1851Z 093DEG 8KT 3199 11122 3168 11117 Carpenter
The Tucson radar (KEMX), 48 km away, was scanning. The volume nearest the first event began at 19:58 UTC.
3 flash flood. Local standard time, as filed.
More than one inch of rain in less than 1 hour in upper reaches of Huachuca Canyon flooded the canyon and flowed across Burt Rd at Fort Huachuca.
Two inches of rain in less than 1 hour caused extensive flooding of Arivaca Road between mile markers 10 and 16 with additional flash flooding farther north near Keystone Peak.
More than 3 inches of rain in 90 minutes in Rio Rico Southwest caused flash flooding more than 1 foot deep across several roadways.
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: 975469, 975474, 975646.