Copious amounts of tropical moisture interacted with a strong upper level low pressure system to produce scattered to numerous showers and thunderstorms across the greater Phoenix metropolitan area during the afternoon and evening hours on September 23rd. Although many of the thunderstorms generated heavy rain which led to flash flooding, a number of the stronger storms also produced large hail due to cooler temperatures in the upper atmosphere. Many places such as Scottsdale and central Phoenix reported hail ranging from one quarter of an inch to one inch or greater in diameter. Fortunately there were few if any reports of damage due to the larger hail. Some of the storms also generated gusty and damaging outflow winds in excess of 50 mph. At 1410MST the public reported multiple large trees downed near Fountain Hills and at 1845MST broadcast media reported that very strong winds uprooted a tree and sent it into a kitchen window about 2 miles east of Paradise Valley.

Hail in MARICOPA, ARIZONA
From 23-SEP-19 17:43:00 to 23-SEP-19 18:45:00 (MST-7)
Location: SCOTTSDALE MUNI
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Scattered to numerous showers and thunderstorms developed across the northeast portion of the greater Phoenix area during late afternoon and early evening hours on September 23rd. In addition to very heavy rain, some of the stronger storms produced large hail up to one inch in diameter, partially the result of cooler temperatures in the upper atmosphere. Several reports of large hail were received in a rather small area of north Scottsdale. At 1743MST, local broadcast media located about one mile southeast of North Scottsdale reported large hail and the hailstones were measured with a diameter of one inch. The stones fell near the intersection of Thunderbird Road and 94th Street. About one hour later and in almost the same location, a trained spotter measured large hail with a diameter of 0.88 inches. Additionally, at 1740MST another trained spotter located 2 miles north of north Scottsdale measured hailstones at 0.88 inches. He reported penny to nickle sized hailstones between Pima Road and Scottsdale Road on the Loop 101. There were no reports of damage associated with the large hail.

Hail in MARICOPA, ARIZONA
From 23-SEP-19 17:04:00 to 23-SEP-19 17:04:00 (MST-7)
Location: BUCKEYE MUNI ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Scattered to numerous thunderstorms developed over the western portions of the greater Phoenix area during the afternoon hours on September 23rd; in addition to locally heavy rain the stronger storms generated large hail, partly due to cooler temperatures in the upper atmosphere. Shortly after 1700MST a trained spotter located 10 miles northwest of Buckeye reported quarter sized hailstones in Tartesso West. He estimated the diameter of the larger stones to be around one inch. No damage was reported due to the large hailstones.

Thunderstorm Wind in MARICOPA, ARIZONA
From 23-SEP-19 06:45:00 to 23-SEP-19 06:45:00 (MST-7)
Location: SCOTTSDALE
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Scattered to numerous thunderstorms developed across the central and northern portions of the greater Phoenix area during the afternoon hours on September 23rd. Although most of the storms generated very heavy rain, leading to multiple flash flood events, a few of the storms did produce gusty and damaging outflow winds. One such storm impacted the north Scottsdale area. According to a report from local broadcast media, gusty winds estimated to be as high as 60 mph uprooted a large tree about 3.5 miles north of Scottsdale. The uprooted tree was near the Indian Bend Wash, just to the west of Hayden Road.

Thunderstorm Wind in PINAL, ARIZONA
From 23-SEP-19 14:38:00 to 23-SEP-19 14:38:00 (MST-7)
Location: APACHE JCT
Magnitude: 48.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

Scattered to numerous showers and thunderstorms developed across eastern portions of the greater Phoenix during the morning and afternoon hours on September 23rd. In addition to locally heavy rain which led to flash flooding, some of the storms produced gusty and damaging outflow winds which impacted the community of Apache Junction. According to a report from the public, at 1438MST gusty winds estimated to be upwards of 55 mph blew shingles off the roof of a home located about one mile east of Apache Junction. The damage occurred north of Broadway Road and near the Apache Trail.

Thunderstorm Wind in MARICOPA, ARIZONA
From 23-SEP-19 18:45:00 to 23-SEP-19 18:45:00 (MST-7)
Location: SCOTTSDALE
Magnitude: 52.00 EG
Property damage: 4.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Scattered to numerous showers and thunderstorms developed across the greater Phoenix area, affecting communities such as Paradise Valley and Scottsdale. In addition to very heavy rain, some of the stronger storms generated gusty and damaging outflow winds. According to a report from local broadcast media, at 1845MST winds estimated to be at least 60 mph in strength uprooted a tree about 2 miles east of Paradise Valley. The tree had an estimated diameter of 6 inches, and was thrown into a kitchen window by the strong gusts. The damage occurred near the Indian Bend Wash, just north of the intersection of Hayden Road and McDonald Drive. There were no reports of injuries.

Thunderstorm Wind in MARICOPA, ARIZONA
From 23-SEP-19 14:10:00 to 23-SEP-19 14:10:00 (MST-7)
Location: FOUNTAIN HILLS
Magnitude: 52.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Public

Scattered to numerous showers and thunderstorms developed across the greater Phoenix area during the afternoon hours on September 23rd; in additions to very heavy rain some of the stronger storms generated gusty and damaging outflow winds that impacted communities such as Fountain Hills and Scottsdale. According to a report from the public, at 1410MST gusty winds estimated to be as high as 60 mph knocked down multiple trees about 5 miles southwest of Fountain Hills. The downed trees were located just to the northeast of Shea Boulevard and Frank Lloyd Wright Boulevard. No injuries occurred from the falling trees.

Hail in MARICOPA, ARIZONA
From 23-SEP-19 17:32:00 to 23-SEP-19 17:32:00 (MST-7)
Location: FENNEMORE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Scattered to numerous showers and thunderstorms developed across the western portion of the greater Phoenix area during the afternoon hours on September 23rd. In addition to very heavy rain, some of the stronger storms generated large hail, partly due to cooler temperatures in the upper atmosphere. At 1732MST, a member of the public located 2 miles southwest of Waddell reported large hail. Hailstones were measured to be about one inch in diameter. The large stones fell near the intersection of Sarival Road and Cactus Road, a few miles northwest of Luke Air Force Base. The large hail could be seen via pictures on social media.

Hail in MARICOPA, ARIZONA
From 23-SEP-19 18:35:00 to 23-SEP-19 18:35:00 (MST-7)
Location: SCOTTSDALE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Scattered to numerous showers and thunderstorms developed across central and eastern portions of the Phoenix area during afternoon and evening hours on September 23rd. In addition to heavy rain, some of the stronger storms produced large hail partly due to the cooler temperatures in the upper atmosphere. Some of the large hail impacted communities such as Scottsdale and Paradise Valley. According to a trained spotter located about one mile southeast of Paradise Valley, large hail fell around 1835MST. The stones fell not fall from the intersection of Scottsdale Road and Lincoln Driver. Some of the larger stones were dime to penny sized with measured diameters of at least 0.75 inches. Gusty winds to 40 mph and minor street flooding were also reported.

Hail in MARICOPA, ARIZONA
From 23-SEP-19 18:40:00 to 23-SEP-19 18:40:00 (MST-7)
Location: PHOENIX
Magnitude: 0.88 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

Scattered to numerous showers and thunderstorms developed across the greater Phoenix metropolitan area, including central Phoenix, during afternoon and early evening hours on September 23rd. In addition to the very heavy rain which led to flash flooding, some storms did produce large hail, partially due to rather cool temperatures in the upper atmosphere. According to a report from the public, at 1840MST large hail fell about 5 miles northeast of Phoenix, just west of Highway 51 and south of Bethany Home Road. The diameter of the larger stones was measured at 0.88 inches. The large hail resulted in a broken skylight. No injuries were reported, however.