Thunderstorms developed during the afternoon and moved northwest across southeast Arizona through the evening. Storms produced damaging winds and large hail across eastern Pima County and the Tohono O'odham Nation and a dust storm in Pinal County.
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.
Thunderstorms developed during the afternoon and moved northwest across southeast Arizona through the evening. Storms produced damaging winds and large hail across eastern Pima County and the Tohono O'odham Nation and a dust storm in Pinal County. The Catalina Foothills were especially hit hard with numerous power poles downed leaving thousands without power for two days.
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 17, 1:04 PM MST, 2 hours 26 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 104 PM MST Mon Jul 17 2023 .SYNOPSIS...The Excessive Heat Warning now continues through Friday with continued record highs possible. Expect a ramp-up in thunderstorm activity as high pressure aloft shifts to a more favorable location near the Four Corners/northern New Mexico. The main threats this afternoon and this evening will be strong outflow winds with the potential for blowing dust, especially across south- central Arizona including the Tucson Metro Area. && .DISCUSSION...Latest IR/WV imagery shows the mid/upper level high near the Four Corners today with easterly mid level flow of around 10-20kts across our area. Cloud build-ups and a few thunderstorms are just getting going over the higher terrain and will continue to expand and move into the valleys over the next few hours. With CAPE values of around 1500-2000 J/KG, DCAPE around 2000 J/KG and effective bulk shear around 20 kts, strong to marginally severe thunderstorms are expected this afternoon into evening with the main concern being strong winds and blowing dust. This is supported by the 12Z HREF which has a large area of greater than 50 percent probability of 30 kt winds with a small area of 90 percent likelihood in south central Pima County. A few spots of locally heavy rain in excess of 1 inch are possible with the strongest storms as well. For the rest of the week, the main story will continue to be the heat as the strong mid/upper level high centered over New Mexico will drift west over Arizona by end of the work week. This will keep the excessive heat going and therefore we've extended the Excessive Heat Warning through Friday. A general easterly mid level flow is expected to sustain itself with PWAT values ranging from 0.75" to 1.5" (lowest east and highest west) this week. That is enough moisture to sustain at least a low to at times mid grade monsoon pattern this week with typical day to day variability. Each day the main threat is expected to be strong gusty winds with only a localized flooding threat. && .AVIATION...valid through 19/00Z SCT clouds AOA 10-15k ft MSL with SCT-BKN SHRA/TSRA and gusts 40-50 kts from 17/22z through 17/04z along the international border with potential impacts for KOLS and KDUG. There is increasing potential for LCL VSBY to 1 SM or less due to BLDU between these times. SFC winds outside storm environment NWLY with speeds ranging btwn 10-18 kts and occasional gusts to 25 mph from 17/17Z to 18/02Z and again aft 18/17Z thru the end of the period. Winds diminish and become light and variable aft 18/05Z. SHRA/TSRA possible aft 18/21Z thru the end of the period. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Thunderstorm activity will increase today over this past weekend, with scattered showers and thunderstorms this afternoon and evening. These storms will be capable of producing strong, gusty and erratic outflow winds to 45 mph, especially across south-central Arizona. Although rainfall will be limited, brief heavy downpours will accompany the stronger storms west of Tucson. 20-foot winds will generally be northwest during each day this week, with occasional gusts to 30 mph due to intense surface heating. Thunderstorm activity will increase to a more typical activity level for the Monsoon season this week. Valley min RH readings 10-20% will continue for most of next week, with readings 20-25% in the higher elevations. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 10 PM MST Friday for AZZ501>509. Blowing Dust Advisory from 1 PM MST this afternoon to 10 PM MST this evening for AZZ502>506. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Special Weather Statement
National Weather Service Tucson AZ
135 PM MST Mon Jul 17 2023
AZZ503-507-513-172115-
Upper San Pedro River Valley including Sierra
Vista/Benson-Dragoon/Mule/Huachuca and Santa Rita Mountains including
Bisbee/Canelo Hills/Madera Canyon-Upper Santa Cruz River and Altar
Valleys including Nogales-
135 PM MST Mon Jul 17 2023
...A strong thunderstorm will impact portions of Santa Cruz County
through 215 PM MST...
At 135 PM MST, Doppler radar was tracking an area of strong
thunderstorm centered near Patagonia Lake State Park, or 10 miles
southeast of Tubac, moving west at 15 mph.
HAZARD...Wind gusts up to 50 mph and pea size hail.
SOURCE...Radar indicated.
IMPACT...Gusty winds could knock down tree limbs and blow around
unsecured objects. Minor damage to outdoor objects is
possible.
Locations impacted include...
Nogales, Tubac, Rio Rico, Patagonia, Sonoita, Nogales International
Airport, Patagonia Lake State Park, Tumacacori, Amado, Kino Springs,
Pena Blanca Lake and Lochiel.
This includes the following highways...
Interstate 19 between mile markers 1 and 29.
Route 82 between mile markers 1 and 32.
Route 83 between mile markers 31 and 33.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
If outdoors, consider seeking shelter inside a building.
&&
LAT...LON 3135 11113 3172 11115 3169 11065 3133 11061
3133 11108
TIME...MOT...LOC 2035Z 099DEG 15KT 3155 11090
MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH
GELThe Tucson radar (KEMX), 81 km away, was scanning. The volume nearest the first event began at 22:32 UTC.
5 thunderstorm wind, 2 hail, 1 flash flood, 1 dust storm. Local standard time, as filed.
A thunderstorm wind gust to 62 mph was measured at the Sasabe RAWS site.
Thunderstorm winds downed two power poles near Miller Ranch Rd northeast of Vail.
Two NWS employees reported quarter size hail on Tucson's east side.
A thunderstorm wind gust of 58 mph was measured at KDMA ASOS at 1634MST. A spotter recorded a gust to 68 mph near Speedway and Harrison at 1635MST and a gust to 63 mph was measured at KTUS ASOS at 1638MST. In the Catalina Foothills from River/Swan to Skyline/Campbell numerous trees were downed, some of which fell on parking structures, vehicles and apartment buildings. Around 7500 customers were without power due to 30 power poles being downed. Winds peeled parts of roofs off a handful of houses.
Thunderstorm winds caused extensive damage to the Fitness Center at the Pima Community College Desert Vista campus. Several trees were downed in Oro Valley. A wind gust to 60 mph was measured at the KAVQ AWOS at 1745MST.
Around 1.5 of rain in less than 1 hour caused flash flooding of roadways in the Catalina Foothills of Tucson from Sunrise and Swan to River and Alvernon.
Thunderstorm outflow winds caused a wall of dust to travel northwest across south central Pinal County. ADOT sensors detected blowing dust reducing visibilities to less than a quarter mile along I-10 from Picacho Peak to Eloy.
Thunderstorm winds downed a power pole near Santa Rosa.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2023Every state in 2023This day in weather historyWarnings in Arizona, July 2023
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: 1120048, 1120052, 1120058, 1120059, 1120061, 1120070, 1121313, 1121314, 1121309.