Monsoon thunderstorms developed across portions of the south central Arizona deserts during the evening hours on August 16th. Some of the stronger storms generated very strong and gusty outflow winds that approached 80 mph in strength at times. At about 2050MST a traveler on Interstate 8 reported significant roof, tree and car damage from a collapsing thunderstorm near the Sentinel rest area. Earlier, at about 1745MST a member of the public located 7 miles northeast of Wittmann reported about 20 trees blown down on a local golf course. The larger trees had diameters of about 12 inches, and the damage was consistent with wind gusts of at least 60 mph. There were no reports of injuries due to the strong and damaging winds.

Thunderstorm Wind in MARICOPA, ARIZONA
From 16-AUG-20 17:44:00 to 16-AUG-20 17:44:00 (MST-7)
Location: WITTMANN
Magnitude: 52.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with strong, damaging outflow winds developed near the town of Wittmann during late afternoon hours on August 16th. At about 1744MST, a member of the public located 7 miles northeast of Wittmann reported that strong winds blew down about 20 trees at a local golf course. The diameter of the largest trees was about 12 inches. Peak wind gusts were estimated by radar to be at least 60 mph in strength. The gusty winds also did additional damage such as to fencing, as reported by the course manager. There were no reports of injury due to the strong winds.

Dust Storm in NORTHWEST PINAL COUNTY, ARIZONA
From 16-AUG-20 17:20:00 to 16-AUG-20 18:10:00 (MST-7)
Crop damage: 0.00K
Reported by: Trained Spotter

Strong to severe thunderstorms produced a large dust storm that moved west to northwest through Pinal county late in the afternoon. Numerous photos and reports were shared about this dust storm. At 1720 MST, a photo on social media showed visibility in Coolidge had fallen to less than 200 feet. Another photo on social media showed visibility on the west side of Casa Grande fell to near zero at 1740 MST. Just to the northwest as the dust storm moved into the town of Maricopa, a couple trained spotters reported visibility fell to less than 100 feet around 1800 MST. Winds were estimated around 45-55 mph with this dust storm as it progressed through Pinal county. A dust storm warning was in effect from 1714 to 1815 MST. No injuries were reported.

Dust Storm in GILA RIVER VALLEY, ARIZONA
From 16-AUG-20 21:05:00 to 16-AUG-20 21:20:00 (MST-7)
Crop damage: 0.00K
Reported by: Public

A very strong thunderstorm near the Maricopa county and Yuma county borders produced a dust storm that traveled west along Interstate-8 in the early nighttime hours. Truck drivers in the area of Dateland reported visibility fell to less than 1/4 mile and driving conditions were treacherous between Dateland and Gila Bend due to the lowered visibility. A dust storm warning was in effect from 2030 to 2130 MST. Winds in the area were estimated around 40-50 mph. No injuries were reported.

Dust Storm in CENTRAL PHOENIX, ARIZONA
From 16-AUG-20 18:30:00 to 16-AUG-20 19:10:00 (MST-7)
Crop damage: 0.00K
Reported by: ASOS

At 1817 MST a NWS employee reported a large wall of dust moving northwest through Tempe. By 1830 MST, the wall of dust reached Sky Harbor International Airport and lowered visibility to less than 1/4 statute mile at 1837 MST. Visibility remained less than 1/4 statute mile until 1858 MST and even fell to 0 statute miles for around 10 minutes during this time. Visibility improved to 5 statute miles around 1910 MST, but light to moderate suspended dust continued to linger through 2140 MST. The dust caused significant delays at the airport. A dust storm warning was in effect from 1803 to 1930 MST for most of the Phoenix metro area. Max wind gusts within the dust storm were measured around 25-30 mph. The dust storm initially developed in northern Pinal county, a dust prone area, due to strong thunderstorm winds and was able to continue through most of the Phoenix metro.

Thunderstorm Wind in MARICOPA, ARIZONA
From 16-AUG-20 20:51:00 to 16-AUG-20 20:51:00 (MST-7)
Location: SENTINEL
Magnitude: 70.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Thunderstorms developed to the southwest of Phoenix during the evening hours on August 16th and some of the stronger storms generated very gusty outflow winds in excess of 60 mph. An employee from the Yuma Fire Department was driving east along Interstate 8 towards Phoenix and as she approached the Sentinel rest area, she reported substantial damage due to a collapsing thunderstorm. The winds produced significant roof, tree and car damage in the area around the rest area, about 2 miles to the west of the town of Sentinel. The winds were estimated to be as high as 80 mph. In addition, hail the size of nickels was reported in association with the thunderstorm.

Thunderstorm Wind in YUMA, ARIZONA
From 16-AUG-20 20:45:00 to 16-AUG-20 20:45:00 (MST-7)
Location: TONTO BASIN
Magnitude: 52.00 EG
Property damage: 475.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A very strong storm moved through the town of Hyder, in far eastern Yuma county north of Interstate-8. The storm produced estimated wind gusts around 50-60 mph. A RAWS station 10-15 miles to the east measured a wind gust of 53 mph at 8:52 PM MST. The thunderstorm winds knocked over 63 power poles along Palomas road between Ave 64E and Agua Caliente Rd, as reported by the Yuma County Sheriff and confirmed by APS electric. APS also reported 300 customers lost power during th height of the storm.