Thunderstorms developed over portions of the greater Phoenix metropolitan area during the afternoon and evening hours on August 20th. Due to the very moist and unstable nature of the atmosphere, the storms generated both very heavy rain and strong, gusty damaging winds, estimated to be in excess of 70 mph. Most of the damage occurred in the communities of Mesa and Chandler during the early evening.

Thunderstorm Wind in MARICOPA, ARIZONA
From 20-AUG-12 19:15:00 to 20-AUG-12 19:15:00 (MST-7)
Location: BUCKHORN
Magnitude: 65.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Scattered thunderstorms developed over the greater Phoenix area during the afternoon and early evening hours on August 20th. Some of the thunderstorms generated both very heavy rain and strong, gusty and damaging microburst winds. According to a trained weather spotter in East Mesa, at 715 pm thunderstorm wind gusts estimated to be at least 65 knots blew down a carport and caused damage to the roof of the home to which the carport was attached. In addition, a number of tree branches with diameters up to 3 inches were downed in the area.

Heavy Rain in MARICOPA, ARIZONA
From 20-AUG-12 19:16:00 to 20-AUG-12 20:00:00 (MST-7)
Location: BUCKHORN
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Scattered thunderstorms developed across the greater Phoenix area during the late afternoon and early evening hours on August 20th, and they affected east valley communities such as Mesa. Due to the very humid and unstable nature of the atmosphere, the thunderstorms were able to produce very heavy rain with rain rates well in excess of 2 inches per hour. An automated Flood Control District gage located near the intersection of Higley and Broadway road measured 1.26 inches of rain between 716 and 801 pm. In addition, a trained weather spotter located about 6 miles east of Mesa measured 1.25 inches of rain between 700 and 735 pm. The intense rainfall led to urban flooding across the eastern portions of the greater Phoenix area during the evening hours.

Thunderstorm Wind in MARICOPA, ARIZONA
From 20-AUG-12 19:05:00 to 20-AUG-12 19:20:00 (MST-7)
Location: HIGHTOWN
Magnitude: 70.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Scattered thunderstorms developed across the greater Phoenix metropolitan area during the late afternoon hours on August 20th and they affected the community of Chandler. The storms generated strong and gusty microburst winds, with peak gusts estimated to be at least 70 knots. Local broadcast media reported that numerous trees were downed across the Chandler Fashion Center north parking lot and along the Loop 101 near Chandler Boulevard. This occurred at approximately 7 pm. Tree trunk diameters were estimated to almost 12 inches at the largest, with additional downed limbs approaching 6 inches in diameter. In addition, at 720 pm a trained weather spotter in Chandler reported trees downed near the intersection of Chandler Boulevard and the 101.

Thunderstorm Wind in MARICOPA, ARIZONA
From 20-AUG-12 19:30:00 to 20-AUG-12 19:30:00 (MST-7)
Location: DESERT SANDS
Magnitude: 65.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

Scattered thunderstorms developed across the greater Phoenix area during the afternoon and early evening hours on August 20th and they affected east valley communities which included Mesa and Superstition Springs. Due to the very moist and unstable nature of the atmosphere, the storms generated strong, gusty and damaging microburst winds. According to a report from the public, at 730 pm gusty winds estimated to be at least 65 knots completely blew down a section block wall at the intersection of Kiowa and Roslyn Street in Mesa. The block wall was was at least 20 feet in length.