Thunderstorms that developed south of the greater Phoenix area shortly before midnight on August 9th stirred up quite a bit of dust which led to dust storm conditions over portions of northwest and western Pinal Counties, as well as far southwest Maricopa County. The dust storms then continued into the very early morning hours, affecting the area from around the town of Maricopa southeast towards Casa Grande. Dust storms also affected the interstate 8 corridor near the Sonoran Desert National Monument to the east of Gila Bend. At 0010MST the official ASOS weather station in Casa Grande measured visibility to one quarter mile in blowing dust. One of the lowest visibility readings came from a trained spotter 8 miles southwest of the Ak-Chin Village; at 0035MST he indicated visibility down to 20 feet in a dust storm. Multiple Dust Storm Warnings were issued for the affected areas.

Dust Storm in NORTHWEST PINAL COUNTY, ARIZONA
From 09-AUG-18 23:45:00 to 10-AUG-18 01:15:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorms developed to the south of Phoenix during the late evening hours on August 9th; the stronger storms produced gusty outflow winds over 40 mph which stirred up areas of blowing dust and created dust storm conditions. The dust storms continued into the very early morning hours on August 10th and affected areas from the town of Maricopa southeast towards Casa Grande. At 0010MST the official Casa Grande AWOS automatic weather station measured visibility down to one quarter mile in dense blowing dust along with 48 mph winds. At 0015MST, the Ak-Chin AWOS station measured visibility at one quarter mile in a dust storm along with 51 mph winds. A Dust Storm Warning was issued for the area and was in effect at the time of the AWOS reports.

Dust Storm in SONORAN DESERT NATL MONUMENT, ARIZONA
From 10-AUG-18 00:30:00 to 10-AUG-18 01:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms continued to develop to the south and southwest of the greater Phoenix area during very early morning hours on August 10th; some of the stronger storms produced outflow winds in excess of 40 mph that stirred up areas of blowing dust and created dust storms conditions. One of the dust storms affected the Interstate 8 corridor to the east of Gila Bend. According to a report from the public, at 0050MST visibility lowered to one quarter mile in a dust storm near Interstate 8, just north of Sonoron Desert National Monument and east of Gila Bend. A Dust Storm Warning was issued for the area at 0030MST and it remained in effect through 0130MST.

Dust Storm in WEST PINAL COUNTY, ARIZONA
From 10-AUG-18 00:30:00 to 10-AUG-18 01:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms continued to develop to the south of Phoenix during the very early morning hours on August 10th; some of the stronger storms generated gusty outflow winds over 40 mph that stirred up areas of dense blowing dust and created dust storm conditions. Some of the dust storms affected the western portion of Pinal County. According to a trained weather spotter located 8 miles southwest of Ak-Chin Village, at 0035MST visibility lowered to just 20 feet in a dust storm. The dense blowing dust was reported west of Highway 347 and just east of the Maricopa County line. A Dust Storm Warning was issued for the area at 0030MST and it remained in effect through 0130MST.