Isolated to scattered thunderstorms developed and moved north across southeast Arizona, primarily south of Interstate 10. One storm caused flash flooding in southern Cochise County and another produced severe wind gusts in the Empire Mountains.
Every event with a place to put it; 2 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.
Isolated to scattered thunderstorms developed and moved north across southeast Arizona, primarily south of Interstate 10. One storm caused flash flooding in southern Cochise County and another produced severe wind gusts in the Empire Mountains.
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 11, 2:40 PM MST, 2 hours 35 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 240 PM MST Sat Jul 11 2020 .SYNOPSIS...Very hot daytime temperatures into early next week, with record or near record highs through Monday. We'll have enough moisture around for isolated to scattered showers and thunderstorms, with the best chances mainly south of Tucson and in the eastern mountains. && .DISCUSSION...The heat is on this weekend with Excessive Heat Warnings in place through Monday across most of the area with Sunday likely the hottest day. Record or near record highs next three days. Mostly sunny to partly cloudy across the area this afternoon. The exception was across the White mountains where it was mostly cloudy with isolated showers/thunderstorms. Afternoon temperatures were at or up to 4 degrees warmer than this time Friday with surface dewpoints in the 40s to mid 50s. Some drier air has moved into the far eastern areas thus PW values this afternoon ranged from 0.80" near AZ/NM border to 1.5" western areas. Steering easterly around 10-15 mph. Outside of the Whites, convection over the higher terrain E/SE of Tucson rather slow. Latest CAMs have mainly isolated thunderstorms moving west across the area through this evening. Best areal coverage for short lived strong storms with localized heavy rain still appears to be across Santa Cruz county and the southern parts of central Pima county or south of Sells. There still remains a slight chance of a brief thunderstorm over the Bighorn Burn scar into early this evening. Sunday still looks like a furnace area wide with the hottest temperatures of the year. Thunderstorm chances remain on the very low end side. Next week: Slight chance of thunderstorms first half of next week and with the high drifting into a more favorable position late in the week an uptick in activity is expected. Temperatures start the week rather hot, near record highs on Monday, then gradually cool closer to normal mid-July values. && .AVIATION...Valid through 13/00Z. SCT-BKN 10-14k ft, SCT-BKN 20k FT with ISOLD -SHRA/TSRA contg into the evening, mainly from KTUS south and east. ISOLD -SHRA/TSRA will diminish after 12/04Z but will is once again expected Sunday after 20Z. Outside of TSRA outflows, SFC winds NWLY 10-14 kts with a few gusts around 20-25 kts through about 12/03Z then becoming variable less than 12 kts the remainder of the forecast period. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...There is a slight chance of mainly afternoon and evening showers and thunderstorms from the Tucson metro area, south and east through Sunday, then mainly south to southeast of Tucson Monday and Tuesday before perhaps an increase in coverage later in the upcoming week. That said the best chances remain along the International Border and across the White Mountains. Through Monday temperatures will peak near or above record levels before easing back to more normal levels next week. Humidity levels will remain close to average through the week with generally good overnight recoveries. 20-ft winds will generally remain less than 15 mph outside of the usual afternoon gustiness due to daytime heating. Also, any afternoon/evening thunderstorms will capable of gusts of 45+ mph. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM MST Monday for AZZ501>509-515. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Special Weather Statement National Weather Service Tucson AZ 352 PM MST Sat Jul 11 2020 AZZ508-512-112315- Chiricahua Mountains including Chiricahua National Monument-Eastern Cochise County Below 5000 Feet including Douglas/Willcox- 352 PM MST Sat Jul 11 2020 ...SIGNIFICANT WEATHER ADVISORY FOR CENTRAL COCHISE COUNTY UNTIL 415 PM MST... At 352 PM MST, Doppler radar was tracking a strong thunderstorm 11 miles west of Chiricahua National Monument, or 21 miles southeast of Willcox, moving west at 15 mph. Dime size hail and wind gusts up to 50 mph will be possible with this storm. This storm will remain over mainly remote areas of central Cochise County. PRECAUTIONARY/PREPAREDNESS ACTIONS... Heavy rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 3214 10944 3200 10943 3195 10972 3218 10972 TIME...MOT...LOC 2252Z 105DEG 14KT 3206 10953 TGD
Special Weather Statement National Weather Service Tucson AZ 444 PM MST Sat Jul 11 2020 AZZ503-513-120015- Dragoon/Mule/Huachuca and Santa Rita Mountains including Bisbee/Canelo Hills/Madera Canyon-Upper Santa Cruz River and Altar Valleys including Nogales- 444 PM MST Sat Jul 11 2020 ...SIGNIFICANT WEATHER ADVISORY FOR SOUTHWESTERN COCHISE AND SOUTHEASTERN SANTA CRUZ COUNTIES UNTIL 515 PM MST... At 443 PM MST, Doppler radar was tracking a strong thunderstorm over Parker Canyon Lake, or 15 miles west of Sierra Vista, moving west at 15 mph. Dime size hail and wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Parker Canyon Lake. PRECAUTIONARY/PREPAREDNESS ACTIONS... Heavy rainfall is also occurring with this storm, and may lead to localized flooding. Do not drive your vehicle through flooded roadways. && LAT...LON 3143 11036 3135 11038 3137 11059 3152 11055 TIME...MOT...LOC 2343Z 105DEG 11KT 3142 11046 TGD
The Tucson radar (KEMX), 83 km away, was scanning. The volume nearest the first event began at 00:25 UTC.
3 thunderstorm wind, 2 dust storm, 1 lightning. Local standard time, as filed.
Strong thunderstorm winds initiated a dust storm near the Willcox Playa that moved west restricting visibility to less than a quarter mile along Interstate 10 between Willcox and Texas Canyon, temporarily halting traffic.
Thunderstorm wind gusts downed six power poles in Sierra Vista near Willcox Rd. and S Carmichael Ave. Wind gusts of 61 mph were reported at KFHU Libby Field ASOS and 79 mph at KALK Pioneer Field ASOS.
Thunderstorm winds downed a tree at the Benson Visitor Center. The falling tree also damaged a pole-mounted gaslight.
Thunderstorms rolled northwest across the Tucson Metro area with thunderstorm outflow winds downing numerous trees and ten power poles. Power was out for several hours for at least 12,000 customers due to downed poles and lines as well as damaged transformers. Power poles were reported down at Broadway and Craycroft, Prince and Flowing Wells and Ina and Oracle. Fallen trees caused damage to the Mission Palms Apartments near Orange Grove and La Cholla. Trees also fell onto a vehicle at River and Craycroft and two cars in Oro Valley. A wind gust to 59 mph was recorded at KDMA Davis-Monthan AFB ASOS.
Lightning struck a house in 26th St and Camino Seco in Tucson. Lightning only caused a small hole in the roof, but fire caused considerable damage to at least one room in the house.
Thunderstorm outflow winds produced blowing dust that restricted visibility to less than a quarter mile along Interstate 10 in northwest portions of the Tucson Metro area, temporarily halting traffic.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Arizona in 2020Every state in 2020This day in weather historyWarnings in Arizona, July 2020
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 2026-10-01. Each event’s entry at NCEI: 912877, 912878, 912881, 912883, 912885, 912884.