Isolated showers and thunderstorms initially began across parts of southern Gila County, along with eastern Maricopa County and northeast Pinal County, producing locally heavy rainfall leading to isolated flash flooding. By the late afternoon and early evening hours on the 20th, new thunderstorms initiated over the high terrain of northern Arizona. High instability (MUCAPE 2,000-2,500 J/kg) aided in maintaining strong to severe thunderstorms into the Phoenix area as thunderstorms pushed toward the south and into the lower deserts during the evening. DCAPE around 1,000-1,200 J/kg promoted strong to severe downbursts with the strongest thunderstorms. Meanwhile, PWATs around 1.7-1.9 aided in thunderstorms being heavy rainfall producers, leading to several reports of flash flooding. No injuries were reported.

Flash Flood in GILA, ARIZONA
From 20-AUG-22 12:40:00 to 20-AUG-22 13:40:00 (MST-7)
Location: MIAMI
Flood cause: Heavy Rain / Burn Area
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Videos showed considerable flow in Bloody Tanks Wash, impacting Schulze Ranch Road. No damage or injuries were reported.

Flash Flood in MARICOPA, ARIZONA
From 20-AUG-22 13:40:00 to 20-AUG-22 14:40:00 (MST-7)
Location: MOBILE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

ADOT reported that SR 238 was closed due to flooding. Timing and exact location estimated from radar. No damage or injuries were reported.

Flash Flood in PINAL, ARIZONA
From 20-AUG-22 14:30:00 to 20-AUG-22 15:30:00 (MST-7)
Location: FLORENCE JCT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

A video showed a wash flowing across a low water crossing along Silver King Road, making the road impassable. Other videos in the Queen Valley area also showed high flow in Queen Creek. Timing estimated from radar. No damage or injuries were reported.

Thunderstorm Wind in MARICOPA, ARIZONA
From 20-AUG-22 20:45:00 to 20-AUG-22 20:45:00 (MST-7)
Location: EL MIRAGE
Magnitude: 50.00 EG
Property damage: 0.50K
Crop damage: 0.00K
Reported by: Trained Spotter

A large tree was uprooted near 91st Avenue and Beardsley Road. No injuries were reported.

Flash Flood in MARICOPA, ARIZONA
From 20-AUG-22 21:30:00 to 20-AUG-22 23:30:00 (MST-7)
Location: WITTMANN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

MCDOT reported that Patton Road between 195th Avenue and 203rd Avenue was closed due to flooding. No damage or injuries were reported.

Flash Flood in MARICOPA, ARIZONA
From 21-AUG-22 04:02:00 to 21-AUG-22 05:55:00 (MST-7)
Location: MATTHIE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: County Official

A FCDMC streamflow gage along Sols Wash exceeded alarm stage, making a low water crossing along Vulture Mine Road impassable. At 0424MST, the gage peaked at a depth of 3.65 feet and a flow of 3,822 CFS. A social media video showed Sols Wash flowing across Vulture Mine Road and Wickenburg dispatch reported the road was closed as a result of the flooding. No damage or injuries were reported.

Flash Flood in LA PAZ, ARIZONA
From 21-AUG-22 01:40:00 to 21-AUG-22 02:40:00 (MST-7)
Location: WENDEN
Flood cause: Heavy Rain
Property damage: 75.00K
Crop damage: 0.00K
Reported by: County Official

Flow in Centennial Wash caused a low water crossing along Centennial Park Road to become impassable. An RV attempted to cross the flooded roadway but was swept off the road. Images also showed damage to the roadway from the flooding. No injuries were reported.

Thunderstorm Wind in MARICOPA, ARIZONA
From 20-AUG-22 20:30:00 to 20-AUG-22 20:30:00 (MST-7)
Location: WITTMANN
Magnitude: 52.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Images showed multiple snapped and uprooted trees in the Sun City Festival area. Some trees knocked down road signs and also fell onto walls and a pergola. No injuries were reported.