Scattered thunderstorms developed and moved west-southwest across southeast Arizona during the late afternoon and early evening. Storms produced wind damage in the northwest Tucson Metro, Sells and Huachuca City.
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.
Scattered thunderstorms developed and moved west-southwest across southeast Arizona during the late afternoon and early evening. Storms produced wind damage in the northwest Tucson Metro, Sells and Huachuca City. The winds also led to the development of a dust storm in Pinal County.
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 Aug 16, 2:30 PM MST, 1 hour 20 minutes earlier.
Area Forecast Discussion National Weather Service Tucson AZ 230 PM MST Sun Aug 16 2020 .SYNOPSIS...Scattered showers and thunderstorms will impact a majority of southeast Arizona into this evening with strong gusty winds, brief heavy rain, and the potential for blowing dust. Thunderstorm activity will diminish later tonight. An extended period of excessive heat can be anticipated into the middle of next week as high pressure remains in the region. There might be a break in the heat from time-to-time as a chance of showers and thunderstorms remain in the forecast. && .DISCUSSION...Upper air plots this morning placed 500 mb high over NW Arizona with NE flow over the area. At 300 mb the center was over SW Arizona. As this center moves N today, this will bring an increase in diffluent flow aloft over the area. PW values ranged from 1" east to 1.6" west with 12z Tucson sounding at 1.24". Surface dewpoints this afternoon ranged from the mid 40's to the lower 60's. The MCV that was over the northern Gulf of California this morning continues to move west this afternoon and was over northern Baja. As expected storms have developed early this afternoon over the eastern Mogollon Rim and the Chiricahua mountains. Some of them looked rather strong. Still on track for storms to propagate S-SW into the evening hours for a nice rim-shot event. Inverted-V profiles suggests strong to severe outflow winds, especially if storms can organize. A severe thunderstorm watch box is not anticipated but conditions will be monitored. Blowing dust is another concern from thunderstorm outflows and in coordination with WFO PSR a blowing dust advisory was hosited for Pinal and Pima counties from 5 pm to 10 pm. Movement of the storms should limit the flash flooding threat, but can't rule it out, especially for the Bighorn burn scar. Much less activity tomorrow as drier pushes in from the east limiting thunderstorm activity to isolated in nature. PW values mostly below 1" across eastern two-thirds of the area. This will continue into Wednesday. Conditions start to change on Thursday as a gulf surge should be on-going thanks the influences of newly named Tropical Storm Genevieve that was located around 330 miles south of Acapulco. Its expected to become a hurricane on Monday as it continues to move NW around 20 mph. Genevieve will be approaching the southern tip of Baja Wednesday night, thus initiating the surge of higher moisture up the Gulf of California. The chances of afternoon/evening storms increase on Thursday with the potential for better chances Friday and Saturday. The strength of the high will be one of the determining factors. Confidence low to moderate. Excessive Heat Warning with record or near record highs through Wednesday then remaining above normal into next weekend. && .AVIATION...Valid through 18/00Z. FEW-SCT clouds at 12k-16k MSL becoming SCT-BKN clouds at 9k-13k ft MSL aft 16/23Z. Isolated to scattered TSRA/SHRA from central Pima county eastward thru 17/05Z, then a slight chance of -TSRA/-SHRA thru 17/12Z. Some storms could be strong to severe late this afternoon and evening with areas of blowing dust and gusts to 50+ kts. Highest threat for TSRA impacting the KTUS/KOLS terminals is between 16/23Z-17/04Z. Otherwise, SFC wind generally less than 12 kts thru the forecast period, except strong and gusty in the vicinity of thunderstorms. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Isolated to scattered afternoon and evening showers and thunderstorms are forecast the next 7 days, with the best chances today and then Friday through next weekend. Temperatures will remain hot through the middle of the upcoming week, lowering several degrees by next weekend. 20-foot winds will follow typical diurnal patterns with the exception of Monday and Tuesday when easterly winds are expected. Wind speeds will be less than 15 mph outside of any thunderstorm gusts. Through Friday, daytime minimum relative humidity will generally be in the 11 to 21 percent range in the valleys and 20 to 30 percent in the mountains, with moderate to good overnight recoveries. && .TWC WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 8 PM MST this evening for AZZ503- 509. Excessive Heat Warning until 8 PM MST Wednesday for AZZ501-502- 504>506. Blowing Dust Advisory from 5 PM this afternoon to 8 PM MST this evening for AZZ504>506. Blowing Dust Advisory from 5 PM this afternoon to 10 PM MST this evening for AZZ502. Blowing Dust Advisory from 8 PM to 10 PM MST this evening for AZZ501. && Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Special Weather Statement National Weather Service Tucson AZ 323 PM MST Sun Aug 16 2020 AZZ506-507-511-514-162315- Santa Catalina and Rincon Mountains including Mount Lemmon/Summerhaven-Upper San Pedro River Valley including Sierra Vista/Benson-Southeast Pinal County including Kearny/Mammoth/Oracle-Galiuro and Pinaleno Mountains including Mount Graham- 323 PM MST Sun Aug 16 2020 ...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN PIMA...WESTERN GRAHAM AND SOUTHEASTERN PINAL COUNTIES UNTIL 415 PM MST... At 322 PM MST, Doppler radar was tracking a strong thunderstorm 7 miles east of San Manuel, or 11 miles southeast of Mammoth, moving west at 5 to 10 mph. Half inch hail and wind gusts up to 50 mph will be possible with this storm. Locations impacted include... Oracle, Mammoth, San Manuel, Campo Bonito and Redington. 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. This storm may intensify, so be certain to monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. && LAT...LON 3284 11048 3253 11039 3237 11052 3266 11084 TIME...MOT...LOC 2222Z 077DEG 6KT 3261 11050 Meyer
Special Weather Statement
National Weather Service Tucson AZ
345 PM MST Sun Aug 16 2020
AZZ505-506-162345-
Southeast Pinal County including Kearny/Mammoth/Oracle-South Central
Pinal County including Eloy/Picacho Peak State Park-
345 PM MST Sun Aug 16 2020
...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN PINAL COUNTY UNTIL
445 PM MST...
At 340 PM MST, an area of strong to severe thunderstorm 10 to 15
miles northeast of Kearny over southern Gila county is expected to
move into northeast Pinal county, moving southwest at 15 mph.
Wind gusts up to 50 mph and small hail will be possible with these
storms.
Locations impacted include...
Kearny, Dudleyville, Aravaipa Canyon Wilderness and Kelvin.
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.
These storms may intensify, so be certain to monitor local radio
stations and available television stations for additional
information and possible warnings from the National Weather Service.
&&
LAT...LON 3298 11078 3303 11073 3307 11073 3308 11069
3310 11068 3311 11065 3314 11064 3314 11062
3293 11046 3277 11079 3314 11110 3325 11095
TIME...MOT...LOC 2240Z 055DEG 12KT 3311 11079
MeyerThe Tucson radar (KEMX), 70 km away, was scanning. The volume nearest the first event began at 22:52 UTC.
5 thunderstorm wind, 2 dust storm, 1 hail, 1 flash flood. Local standard time, as filed.
Thunderstorm winds downed several trees in Catalina.
Thunderstorm winds downed power poles along Silverbell Road north of Sunset Rd in northwest Tucson. Downed power lines started a brush fire.
Thunderstorm winds downed tree limbs that fell on and damaged a carport in Huachuca City. The residence also sustained minor roof and siding damage.
Thunderstorm outflow winds created a large dust storm that moved southwest across southern Pinal County, crossing traffic delays along Interstate 10 as visibility was reduced to near zero.
KAVQ AWOS at Marana Airport recorded a thunderstorm wind gust to 62 mph.
Thunderstorms produced between 1 and 1.5 inches of rain in 60 to 90 minutes. Wilds Rd. in Catalina had over 8 inches of flood waters flowing across it near Twin Lakes Rd.
Thunderstorm outflow winds caused a large dust storm to move southwest across southern Pinal County into parts of the Tohono O'odham Nation in southwest Pinal County. Visibility for motorists was reduced to less than a quarter mile.
Thunderstorm winds downed two power poles near Sells.
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, August 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 2026-09-24. Each event’s entry at NCEI: 919544, 919546, 919547, 919548, 919551, 919552, 919553, 919549, 919554.