Scattered monsoon thunderstorms developed during the evening hours across much of the greater Phoenix metropolitan area on August 12th. The primary weather hazards associated with the storms were gusty and damaging outflow winds along with areas of dense blowing dust. Dense blowing dust and dust storm conditions with visibility down to near zero miles occurred from central Phoenix south through communities such as Chandler, and then as far south as Casa Grande. Numerous reports of significant wind damage were received from trained spotters, the public and broadcast media. Virtually all of the damage involved downed trees, such as the public report of a large eucalyptus tree that was blown into an apartment building at the intersection of Mill and Southern Avenue. There were no reports of injuries despite the numerous reports of wind damage across the Phoenix area.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 17:57:00 to 12-AUG-18 17:57:00 (MST-7)
Location: SCOTTSDALE MUNI
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorms with strong gusty outflow winds moved through the community of Scottsdale during the early evening hours on August 12th. At 1757MST the official ASOS weather station at the Scottsdale airport measured a wind gust of 58 mph.

Dust Storm in NORTH PHOENIX/GLENDALE, ARIZONA
From 12-AUG-18 18:00:00 to 12-AUG-18 18:45:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with gusty outflow winds affected the northern portion of the greater Phoenix metropolitan area during the late afternoon and early evening hours on August 12th; the stronger storms generated gusty outflow winds over 30 mph that created areas of dense blowing dust and associated dust storm conditions. At 1804MST a member of the public reported visibility lowered to one quarter of a mile in a dust storm, near the intersection of Bell Road and Tatum Boulevard. A Dust Storm Warning had been issued for the area just one minute prior to the public report, and the warning remained in effect through 1845MST.

Dust Storm in SCOTTSDALE/PARADISE VALLEY, ARIZONA
From 12-AUG-18 17:45:00 to 12-AUG-18 18:30:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with gusty outflow winds affected portions of the greater Phoenix area during the late afternoon and early evening hours on August 12th; some of the stronger storms generated outflow winds over 40 mph that created areas of dense blowing dust, affecting communities such as Scottsdale and Paradise Valley. Multiple trained spotters reported dust storm conditions near 1800MST. A trained spotter 1 mile southeast of Paradise Valley reported visibility below one quarter of a mile in a dust storm near the intersection of Scottsdale Road and McDonald Drive. A second trained spotter 2 miles south of Scottsdale reported visibility down to 100 feet in a dust storm near the intersection of McDowell Road and 74th Street. A Dust Storm Warning was issue just minutes after the spotter reports were received. No injuries were reported due to the sharply reduced visibility and associated hazardous driving conditions.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:20:00 to 12-AUG-18 18:20:00 (MST-7)
Location: MC QUEEN
Magnitude: 61.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with strong, gusty and damaging outflow winds moved across the southeast portion of the greater Phoenix area, including the community of Tempe, during the early evening hours on August 12th. One of the stronger storms resulted in two instances of wind damage just north of Broadway Road in north Tempe. According to one report from the public, at 1820MST a large tree was knocked over onto two vehicles near the intersection of Dobson Road and Main Street, just north of Broadway Road. Wind gusts were estimated to be as high as 70 mph. The tree had a trunk with a diameter of about 18 inches. At the same time, another public report indicated that asphalt shingles had been blown off of a roof near the intersection of Broadway Road and McClintock Drive. The assciated wind gusts were estimated to be a bit less, closer to 60 mph. No reports of injuries were received due to the fallen tree.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 17:33:00 to 12-AUG-18 17:33:00 (MST-7)
Location: FOUNTAIN HILLS
Magnitude: 56.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with strong and damaging outflow winds moved across higher terrain locations to the northeast of Phoenix during the early evening hours on August 12th. One of the stronger storms affected the community of Fountain Hills. At 1733MST a trained spotter located 1 mile east of Fountain Hills reported that gusty winds knocked down a large eucalyptus tree next to the Fountain Hills Town Hall. Winds were estimated to be at least 65 mph in strength. No injuries were reported due to the fallen tree.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:11:00 to 12-AUG-18 18:11:00 (MST-7)
Location: MESA
Magnitude: 52.00 EG
Property damage: 8.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with strong, gusty and damaging outflow winds moved through the eastern portion of the greater Phoenix area, including the community of Mesa, during the early evening hours on August 12th. According to a trained spotter located about 2 miles northwest of Mesa, at 1811MST outflow winds knocked over several trees estimated to be around 20 feet tall. The winds also resulted in a power outage. The trees were downed just east of the intersection of Rio Salado Parkway and Alma School Road. Wind gusts were estimated to be between 45 and 60 mph.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:24:00 to 12-AUG-18 18:24:00 (MST-7)
Location: FALFA
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with gusty and damaging outflow winds moved through the southeast portion of the greater Phoenix metropolitan area during the early evening hours on August 12th. One of the stronger storms affected communities such as Tempe and Chandler. According to a trained spotter located 4 miles north of Chandler, at 1824MST gusty winds estimated to be as high as 70 mph knocked over a tree just east of the intersection of Dobson Road and Elliot Road. The trunk of the tree was estimated to be about 12 inches wide. At exactly the same time, another trained spotter located just west of the same intersection reported multiple trees down. No injuries were reported due to the downed trees.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:25:00 to 12-AUG-18 18:25:00 (MST-7)
Location: HIGHTOWN
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with strong and gusty outflow winds moved through the southeast portion of the greater Phoenix area, including the community of Tempe, during the early evening hours on August 12th. According to a trained weather spotter located 3 miles northwest of Chandler, at 1825MST outflow winds estimated to be at least 65 mph in strength knocked down 2 trees near the intersection of Warner Road and the Loop 101 Freeway in Tempe. No injuries were reported.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:22:00 to 12-AUG-18 18:22:00 (MST-7)
Location: TEMPE
Magnitude: 61.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with strong gusty outflow winds moved through the southeast portion of the greater Phoenix area during the early evening hours on August 12th. One of the stronger storms moved across the community of Tempe. According to a member of the public located about 1 mile west of Tempe, at 1822MST gusty winds estimated to be as high as 70 mph downed a large eucalyptus tree; the tree was knocked over and onto an apartment building near the intersection of Mill Avenue and Southern Avenue. No injuries were reported due to the downed tree.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:19:00 to 12-AUG-18 18:19:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorms with strong and gusty outflow winds moved through the central portion of the greater Phoenix area, including downtown Phoenix and Sky Harbor Airport, during the early evening hours on August 12th. At 1819MST the official ASOS weather station at Phoenix Sky Harbor International Airport measured a wind gust of 58 mph.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 17:55:00 to 12-AUG-18 17:55:00 (MST-7)
Location: SCOTTSDALE MUNI
Magnitude: 56.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with strong and damaging outflow winds moved across the northern portion of the greater Phoenix metropolitan area during the early evening hours; one of the stronger storms affected the community of Scottsdale. According to a report from the public, at 1755MST gusty winds estimated to be at least 65 mph in strength blew down a large eucalyptus tree near the intersection of Cactus Road and 81st Street. The  downed tree was located about 2 miles southwest of north Scottsdale. There were no reports of injuries due to the fallen tree.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 17:58:00 to 12-AUG-18 17:58:00 (MST-7)
Location: SCOTTSDALE MUNI
Magnitude: 61.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with strong and damaging outflow winds moved across the northern portion of the greater Phoenix metropolitan area during the early evening hours on August 12th. One of the stronger storms affected the community of Scottsdale. According to a trained spotter located 3 miles southwest of north Scottsdale, at 1758MST gusty winds estimated to be nearly 70 mph in strength uprooted a tree with a diameter of 20 inches. The tree was downed near the intersection of Thunderbird Road and 60th Street.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:17:00 to 12-AUG-18 18:45:00 (MST-7)
Location: CHANDLER HGTS
Magnitude: 63.00 MG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with very strong, damaging outflow winds moved across the far southeast portion of the greater Phoenix metropolitan area during the early evening hours on August 12th. Some of the stronger storms affected the communities of Chandler and Queen Creek. At 1817MST a trained weather spotter located 4 miles west of Queen Creek measured a wind gust of 72 mph. The gust was observed just southeast of the intersection of Higley Road and Chandler Heights Road. Shortly afterward, at 1844MST, the same spotter reported that many mature Palo Verde trees were blown down by the strong microburst winds. No injuries were reported as a result of the fallen trees.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:25:00 to 12-AUG-18 18:25:00 (MST-7)
Location: TREMAINE
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with strong gusty outflow winds affected the eastern portion of the greater Phoenix metropolitan area during the early evening hours on August 12th. One of the stronger storms moved over the communities of Tempe and Mesa. At 1825MST a trained weather spotter located 4 miles southeast of Tempe measured a wind gust of 63 mph. The gust was observed just southeast of the intersection of Dobson Road and Guadaupe Road.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:09:00 to 12-AUG-18 18:09:00 (MST-7)
Location: BOYS RANCH
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with strong and gusty outflow winds moved across the far southeast portion of the greater Phoenix area during the early evening hours on August 12th. One of the stronger storms moved across the community of Queen Creek. At 1809MST a member of the public measured a wind gust to 58 mph about 2 miles northeast of the town of Queen Creek. The gust occurred near the intersection of Crismon Road and Queen Creek Road. No reports of damage were received. He also mentioned that one half inch of rain fell with the strong thunderstorm.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 17:45:00 to 12-AUG-18 17:46:00 (MST-7)
Location: SCOTTSDALE MUNI
Magnitude: 61.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorms with strong, gusty and damaging outflow winds moved across the northeast portion of the greater Phoenix area during the late afternoon hours on August 12th. Some of the storms affected North Scottsdale, in the area near Shea Boulevard and east of the Loop 101 freeway. At 1746MST local broadcast media reported that gusty winds estimated to be nearly 70 mph blew over a very large tree onto two vehicles near the intersection of Shea Boulevard and 110th Street. The tree had an estimated diameter of about 18 inches. At nearly the same time, the public reported that a large tree was blown over just north of Shea Boulevard and near Frank Lloyd Wright Boulevard. The tree was downed and lying in the road blocking traffic. No injuries were reported in either case.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:13:00 to 12-AUG-18 18:15:00 (MST-7)
Location: FALFA
Magnitude: 56.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorms with gusty and damaging outflow winds moved across the eastern portions of the greater Phoenix metropolitan area during the late afternoon and early evening hours on August 12th. Some of the stronger storms affected communities such as Gilbert and Chandler. At 1813MST, local broadcast media reported that gusty outflow winds estimated to be at least 65 mph blew down a large eucalyptus tree near the intersection of Alma School Road and Elliot Road. The downed tree was about 3 miles west of the town of Gilbert. No injuries were reported due to the falling tree.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:34:00 to 12-AUG-18 18:34:00 (MST-7)
Location: CHANDLER HGTS
Magnitude: 56.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with strong gusty outflow winds moved across the southeast portion of the greater Phoenix metropolitan area during the early evening hours on August 12th and one of the stronger storms affected communities of Queen Creek and Chandler Heights. At 1834MST a trained spotter located 4 miles southwest of Queen Creek reported a number of downed trees on Riggs Road between Ellsworth Road and Val Vista Road. Some of the trees were blocking the road and forcing drivers to drive around the fallen trees. No accidents were reported however.

Dust Storm in NORTHWEST PINAL COUNTY, ARIZONA
From 12-AUG-18 17:30:00 to 12-AUG-18 19:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with gusty outflow winds affected areas to the southeast of Phoenix during the late afternoon and early evening hours on August 12th. Some of the stronger storms produced gusty outflow winds in excess of 40 mph that stirred up areas of dense blowing dust and created dust storm conditions; areas affected included the Interstate 10 corridor as well as the communities of Florence and Casa Grande. At 1734MST, a member of the public located about 4 miles north of Florence reported visibility down to one eighth of mile in a dust storm along Highway 79. At 1831MST another member of the public 4 miles west of Santan reported less than one quarter of a mile visibility in blowing dust along Interstate 10 near the Gila River Bridge. Additionally, at 1855MST an automated AWOS weather station 9 miles southeast of Maricopa measured visibility at one quarter of a mile in blowing dust. Although dust storm conditions were not reached, at 1832MST another automated AWOS station 5 miles north of Casa Grande measured visibility at one half mile in blowing dust along with winds gusts to 52 mph. A Dust Storm Warning had been issued for much of the area starting at 1740MST and running through 1845MST.  No accidents or injuries were reported despite the sharply reduced visibility and hazardous driving conditions.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:00:00 to 12-AUG-18 18:00:00 (MST-7)
Location: PARADISE VLY
Magnitude: 61.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with strong and damaging outflow winds moved through areas to the northeast of Phoenix during the early evening hours on August 12th. Some of the stronger storms affected communities such as Paradise Valley and Scottsdale. According to a trained spotter located about 1 mile northeast of Paradise Valley, at 1800MST gusty winds estimated to be as high as 70 mph knocked down a number of Palo Verde trees near the intersection of Scottsdale Road and Indian Bend Road. No injuries were reported due to the falling trees.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 19:36:00 to 12-AUG-18 19:36:00 (MST-7)
Location: WITTMANN
Magnitude: 61.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with strong and damaging outflow winds moved across the northwest portion of the greater Phoenix area during the evening hours on August 12th. One of the stronger storms moved through the community of Wittmann. According to a social media report from the public, at 1936MST gusty outflow winds estimated as high as 70 mph downed a number of power poles into the road near the intersection of 211th Avenue and Dove Valley Road. The downed poles and lines resulted in a power outage in Wittmann. The downed poles were about 1 mile to the northeast of Wittmann. No injuries were reported due to the fallen power poles and power lines.

Dust Storm in SOUTHEAST VALLEY/QUEEN CREEK, ARIZONA
From 12-AUG-18 18:00:00 to 12-AUG-18 19:00:00 (MST-7)
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with gusty outflow winds affected the southeast portion of the greater Phoenix metropolitan area during the early evening hours on August 12th; the stronger storms generated gusty winds over 40 mph that stirred up areas of dense blowing dust and created dust storm conditions across portions of Chandler and Sun Lakes. Multiple reports were received of dust storms conditions, from trained spotters as well as the public. At 1820MST a trained spotter 4 miles southeast of Chandler reported visibility down to zero miles in a dust storm near the intersection of the San Tan Freeway and Cooper Road. At 1829MST a second trained spotter 2 miles southeast of Chandler reported visibility in a dust storm near the intersection of Price Road and Germann Road. He indicated that the dust storm was moving west towards Interstate 10. Finally, at 1847MST a member of the public located 3 miles west of Sun Lakes reported visibility down to one eighth of a mile in a dust storm at the intersection of Interstate 10 and Riggs Road. No accidents or injuries were reported due to sharply restricted visibility and hazardous driving conditions.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:18:00 to 12-AUG-18 18:18:00 (MST-7)
Location: CHANDLER ARPT
Magnitude: 61.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorms with gusty and damaging outflow winds affected the southeast portion of the greater Phoenix metropolitan area during the early evening hours on August 12th; one of the stronger storms impacted the community of Chandler. According to a trained spotter located about 3 miles southeast of the Chandler Municipal Airport or 5 miles southwest of Higley, gusty outflow winds estimated at 70 mph downed a large Palo Verde tree near the intersection of Lindsay Road and Ocotillo Road. The base of the tree had a diameter of about 15 inches.

Thunderstorm Wind in MARICOPA, ARIZONA
From 12-AUG-18 18:20:00 to 12-AUG-18 18:20:00 (MST-7)
Location: TREMAINE
Magnitude: 61.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorms with strong and damaging outflow winds moved through the eastern portion of the greater Phoenix area during the early evening hours on August 12th. One of the stronger storms affected the community of Tempe. According to a report from the public, at 1820MST gusty outflow winds estimated at 70 mph downed a large pine tree about 3 miles southeast of Tempe. The tree was knocked into an apartment building in Dobson Ranch which is located to the southeast of the intersection of the Superstition Freeway and the Loop 101 freeway. There were no reports of injuries due to the fallen pine tree.