An upper level low pressure system moved eastward across southern Arizona on May 9th. Southeast flow ahead of the low advected moisture into eastern Arizona, and scattered thunderstorms developed across portions of south central Arizona during the afternoon hours. A few of the storms generated strong and damaging microburst winds, in addition to locally heavy rain and small hail.

Thunderstorm Wind in MARICOPA, ARIZONA
From 09-MAY-12 16:38:00 to 09-MAY-12 17:00:00 (MST-7)
Location: GILBERT
Magnitude: 65.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

An upper level low pressure system moving east across southern Arizona spread moisture into eastern Arizona and led to scattered thunderstorms across the central deserts during the afternoon hours on May 9th. A few storms generated gusty and damaging winds estimated to be in excess of 60 knots. At 439 PM, a trained weather spotter reported that small trees and large limbs were down over the road at Ray and Cooper in Gilbert. Another weather spotter in Chandler reported that three large trees, all of them 36 inches wide, were blown over near south Dobson road and East Market Place at approximately 5 PM. Pictures of the downed trees were taken and sent to the Phoenix WCM.

Thunderstorm Wind in MARICOPA, ARIZONA
From 09-MAY-12 16:30:00 to 09-MAY-12 18:00:00 (MST-7)
Location: PHOENIX
Magnitude: 50.00 EG
Property damage: 70.00K
Crop damage: 0.00K
Reported by: Utility Company

Southeast flow ahead of a vigorous upper level low pressure system spread moisture into south central Arizona on May 9th. This led to the development of scattered thunderstorms over the central deserts during the afternoon and early evening hours. A few storms in the greater Phoenix area produced damaging microburst winds, estimated to be 50 knots or higher. According to SRP, a local utility company, the winds downed 9 12-kilovolt poles, most of them in north-central Phoenix. Over 4800 people were without power at the peak of the storms.

Thunderstorm Wind in PINAL, ARIZONA
From 09-MAY-12 16:35:00 to 09-MAY-12 16:35:00 (MST-7)
Location: MAGMA
Magnitude: 70.00 EG
Property damage: 150.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A low pressure system moving east across southern Arizona spread moisture into south central Arizona which led to scattered thunderstorms over the lower deserts during the afternoon hours on May 9th. According to a trained weather spotter, microburst wind gusts estimated at 70 knots damaged 8 mobile homes in the Pleasant Valley Mobile Home Park at approximately 435 PM. The park was located near Germain and Ironwood, about 5 miles east of Queen Creek. Six of the homes had their northeast-facing awnings removed. The strong winds lifted up the overhangs and in some cases removed portions of the roofs. Many of these homes were blown off of their foundations. The strong microburst winds were likely enhanced by a gustnado, which increased the severity of the damage. In addition to the mobile home damage, the strong winds blew down a number of power lines in the area.

Heavy Rain in MARICOPA, ARIZONA
From 09-MAY-12 16:45:00 to 09-MAY-12 17:30:00 (MST-7)
Location: GOLDEN HILLS
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

An upper level low pressure system moving east across Arizona spread moisture into south central Arizona, and led to the development of scattered afternoon thunderstorms on May 9th. Some of the storms produced locally heavy rainfall, in addition to strong and damaging microburst winds. At 515 PM, a trained weather spotter in east Mesa reported localized street flooding on Broadway road between Sossamon and 80th Street. A nearby Guadalupe Channel ALERT site measured 0.91 inches of rainfall. The street flooding created hazardous driving conditions during the late afternoon rush hour.

Thunderstorm Wind in MARICOPA, ARIZONA
From 09-MAY-12 18:15:00 to 09-MAY-12 18:15:00 (MST-7)
Location: GILA BEND
Magnitude: 60.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Utility Company

An upper level low moving east across southern Arizona spread moisture into south central Arizona and led to scattered thunderstorms during the afternoon and evening hours on May 9th. Some of the storms in the Gila Bend area produced damaging microburst winds with peak gusts estimated to be at least 60 knots. As reported by the local utility company, at approximately 615 PM the gusty winds downed a tree which blocked traffic on Pima Road and Highway 85. Construction debris from Interstate 8 and Bypass 85 was strewn about by the strong winds. In addition, power lines were downed by sustained winds reported to be in excess of 45 mph and this left most of the town of Gila Bend without power.

Thunderstorm Wind in PINAL, ARIZONA
From 09-MAY-12 17:00:00 to 09-MAY-12 17:00:00 (MST-7)
Location: CASA BLANCA
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

An upper level low pressure system moving eastward across southern Arizona spread moisture into eastern Arizona and scattered thunderstorms developed over the central deserts during the afternoon hours on May 9th. A few of the storms generated strong, damaging microburst winds. At 5 PM, a 58 MPH wind gust was measured four miles north of the town of Maricopa. The wind gust was reported by an official COOP weather observer.