A deep southerly fetch of rich moisture up from the Gulf of California led to scattered to widespread heavy rainfall in portions of Southwest Arizona during the afternoon of the 1st. Moisture values were well above normal for the time of year with precipitable water values analyzed around 2.0-2.2 inches. Favorable dynamic and orographic forcing helped lead to strong updrafts and training of storms over certain terrain areas. Radar estimated rain rates were up to around 2-3 inches per hour with locally higher rates over shorter periods. These high rain rates led to areas of high rainfall accumulation, with some areas of more than 1 inch of rain and isolated areas up to 2.5-3.5 inches, radar estimated. Highest measured rainfall were between 1.5-2.0 inches. This resulted in multiple reports of flash flooding in the region, including flooding of the Gila River in Yuma County. On top of the flooding, the heavy mass loading, strong updrafts, and strong cold pools resulted in strong to severe outflow winds emanating out from the showers and storms. , which led to a few severe wind reports and generated dust storm conditions in some areas.

Thunderstorm Wind in YUMA, ARIZONA
From 01-SEP-23 11:49:00 to 01-SEP-23 11:49:00 (MST-7)
Location: YUMA PROVING GROUND
Magnitude: 54.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A Yuma Proving Ground Station located about 15 miles north of I-8 between Wellton and Tacna measured a 62 mph gust.

Thunderstorm Wind in YUMA, ARIZONA
From 01-SEP-23 13:16:00 to 01-SEP-23 13:16:00 (MST-7)
Location: PIONEER
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A Yuma Proving Ground Station located just west of Highway 95 at approximately 15 miles south of Quartzsite measured a gust of 60 mph.

Dust Storm in YUMA, ARIZONA
From 01-SEP-23 13:45:00 to 01-SEP-23 14:05:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Visibility down to as low as 1/4 mile was reported along I-8 between East 16th street and South Pacific Avenue in Yuma by trained spotter. No accidents or injuries were reported.

Dust Storm in YUMA, ARIZONA
From 01-SEP-23 12:40:00 to 01-SEP-23 13:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Video of visibility of less than 1/4 mile in blowing dust from outflow winds from distant thunderstorms along County 14th Street near Avenue 5E in Yuma. No accidents or injuries were reported.

Dust Storm in GILA RIVER VALLEY, ARIZONA
From 01-SEP-23 12:15:00 to 01-SEP-23 12:35:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Video showed near zero Visibility along I-8 in the Tacna/Roll area due to blowing dust from thunderstorm outflow winds. No accidents or injuries were reported.

Dust Storm in YUMA, ARIZONA
From 01-SEP-23 13:02:00 to 01-SEP-23 13:22:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Arizona Department of Transportation traffic camera along I-8 nearing the Arizona and California state line in Yuma showed visibility down to 1/4 mile in blowing dust from outflow winds from distant thunderstorm activity with wind gusts estimated at between 40-50 mph. No accidents or injuries were reported.

Flash Flood in YUMA, ARIZONA
From 01-SEP-23 13:00:00 to 01-SEP-23 16:00:00 (MST-7)
Location: FISHERS LNDG
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Department of Highways

Report of flooding on Highway 95 near mile post 59. Timing based on radar. No damages or injuries were reported.

Dust Storm in YUMA, ARIZONA
From 01-SEP-23 12:53:00 to 01-SEP-23 13:13:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Yuma International Airport recorded a visibility of less than 1/4 mile in blowing dust due to outflow winds from distant thunderstorm activity. Winds gusts from the outflow were measured at 40-50 mph.

Flash Flood in YUMA, ARIZONA
From 01-SEP-23 14:00:00 to 01-SEP-23 17:00:00 (MST-7)
Location: ROLL NTLPE RANCH ARP
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Public

Video evidence showed considerable flow from the Gila River that resulted in erosion along Mohawk Valley Road, located approximately 5 miles west-northwest of Tacna. Timing estimated from radar. A USGS gauge on the Gila River near Dome/Yuma, roughly 25 miles downstream, recorded a rapid 4-foot rise later in the evening. No injuries were reported.

Flash Flood in YUMA, ARIZONA
From 01-SEP-23 13:45:00 to 01-SEP-23 15:45:00 (MST-7)
Location: GROWLER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Rural road between County 2nd St and County 3rd St near Tacna closed due to significant flow from Gila River. Timing estimated based on radar. No damages or injuries were reported.

Flash Flood in YUMA, ARIZONA
From 01-SEP-23 13:00:00 to 01-SEP-23 15:00:00 (MST-7)
Location: FISHERS LNDG
Flood cause: Heavy Rain
Property damage: 1.00K
Crop damage: 0.00K
Reported by: Public

Significant water flow across the Martinez Lake area, resulting in road damage. Timing based on radar. No injuries were reported.