A large and vigorous upper level low pressure system was situated over the desert southwest on September 27th; the associated cold front moved east across the central deserts during the afternoon hours. Lingering monsoonal moisture combined with high instability and strong wind fields to generate a squall line with damaging winds which spread east across the entire greater Phoenix metropolitan area during the middle of the afternoon. Damaging straight-line winds in excess of  60 mph downed numerous trees and power poles in the greater Phoenix area and also caused roof damage in places. No injuries were reported due to the squall line.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:10:00 to 27-SEP-14 14:10:00 (MST-7)
Location: GLENDALE MUNI ARPT
Magnitude: 43.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe squall line moved east across the western portion of the greater Phoenix metropolitan area during the middle of the afternoon on September 27th, and the associated thunderstorms generated gusty and damaging microburst winds in portions of the community of Glendale. According to a trained weather spotter located just to the southwest of the Arizona State University West Campus, gusty winds estimated to be at least 50 mph caused roof damage and also blew down an awning in a local trailer park. In addition, the strong winds caused a power outage in the area. Locally heavy rainfall accompanied the passage of the squall line; 1.5 inches of rain was measured within 30 minutes and street flooding occurred as a result.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:31:00 to 27-SEP-14 14:31:00 (MST-7)
Location: PHOENIX
Magnitude: 65.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe squall line moved east across central Phoenix during the middle of the afternoon on September 27th, and the stronger thunderstorms produced strong and damaging winds estimated to be at least 65 mph. According to a trained weather spotter in central Phoenix, gusty winds blew down a 12 inch diameter tree near the intersection of East McDowell Road and 17th Street. The tree was downed in the parking lot of a local hospital; fortunately no injuries or damage to cars was reported.

Thunderstorm Wind in PINAL, ARIZONA
From 27-SEP-14 16:37:00 to 27-SEP-14 16:40:00 (MST-7)
Location: MAGMA
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe squall line moved eastward across the southeastern portion of the greater Phoenix metropolitan area during the middle of the afternoon on September 27th, and the stronger storms brought strong and damaging winds to San Tan Valley. According to a trained weather spotter in San Tan Valley, thunderstorm microburst wind gusts estimated to be nearly 65 mph downed five trees. The diameter of the trees ranged from 12 to 14 inches.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 15:39:00 to 27-SEP-14 15:40:00 (MST-7)
Location: HARMONY VILLA
Magnitude: 61.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: NWS Employee

A severe squall line moved east across the eastern portion of the greater Phoenix area during the middle of the afternoon on September 27th, and the stronger thunderstorms produced damaging winds that affected communities such as Mesa. According to a National Weather Service Employee in east Mesa, gusty microburst winds estimated to be nearly 70 mph blew down a large tree with a diameter of two feet. The tree, located near the intersection of North Power Road and East McKellips Road, fell down and blocked a roadway.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:28:00 to 27-SEP-14 14:28:00 (MST-7)
Location: PHOENIX DEER VLY ARP
Magnitude: 62.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A severe squall line moved east across the northern portion of the greater Phoenix metropolitan area during the middle of the afternoon on September 27th. The squall line brought very strong and gusty winds to Deer Valley; the official ASOS wind sensor at the Deer Valley airport measured a peak gust to 62 knots. No damage was reported at the airport.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:37:00 to 27-SEP-14 14:37:00 (MST-7)
Location: CHANDLER ARPT
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

A severe squall line moved across the greater Phoenix metropolitan area during the middle of the afternoon on September 27th; strong and gusty winds were observed in the community of Chandler. The official ASOS wind sensor at the Chandler airport measured a peak gust to 50 knots.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 15:46:00 to 27-SEP-14 15:46:00 (MST-7)
Location: GLENDALE MUNI ARPT
Magnitude: 65.00 MG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe squall line moved east across the western portion of the greater Phoenix metropolitan area during the middle of the afternoon on September 27th. The squall line brought strong, gusty and damaging winds to the town of Glendale. According to the official wind sensor at the Glendale airport, a peak wind gust of 65 knots was recorded. The wind was sufficient to peel off roofing tiles from a nearby building.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:50:00 to 27-SEP-14 14:50:00 (MST-7)
Location: KENDALL
Magnitude: 52.00 EG
Property damage: 20.00K
Crop damage: 0.00K
Reported by: Trained Spotter

A severe squall line moved east and across the central portion of the greater Phoenix metropolitan area during the middle of the afternoon on September 27th; as the line moved through it generated gusty and damaging winds estimated to be in excess of 60 mph. According to a trained weather spotter, straight-line microburst winds knocked down freeway signs on the highway 143 Salt River bridge, located just to the east of Phoenix Sky Harbor International Airport.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:18:00 to 27-SEP-14 14:18:00 (MST-7)
Location: GLENDALE MUNI ARPT
Magnitude: 56.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A severe squall line moved east across the western portion of the greater Phoenix metropolitan area during the middle of the afternoon on September 27th, and the associated thunderstorms brought gusty and damaging winds to communities such as Glendale. According to a report from local broadcast media, damaging microburst winds estimated to be as high as 65 mph blew down a power pole near the intersection of West Thunderbird Road and North 59th Avenue, about 3 miles north of Glendale Municipal Airport. The power pole fell on a car and blocked the road.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:45:00 to 27-SEP-14 15:11:00 (MST-7)
Location: SCOTTSDALE
Magnitude: 52.00 EG
Property damage: 8.00K
Crop damage: 0.00K
Reported by: Amateur Radio

A severe squall line moved east across the greater Phoenix metropolitan area during the middle of the afternoon on September 27th, and the stronger thunderstorms brought strong and damaging winds to communities such as Scottsdale and Deer Valley. According to an amateur radio operator in south Scottsdale, thunderstorm microburst winds estimated to be at least 60 mph blew down several trees located at the intersection of east Thomas Road and the Pima Freeway (Loop 101). Additionally, a trained weather spotter reported an 8 inch diameter tree downed to the southeast of the Deer Valley airport.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:30:00 to 27-SEP-14 15:30:00 (MST-7)
Location: (PHX)SKY HARBOR ARPT
Magnitude: 61.00 EG
Property damage: 100.00K
Crop damage: 0.00K
Reported by: County Official

A severe squall line moved east across Phoenix Sky Harbor Airport during the middle of the afternoon on September 27th, and the associated thunderstorms generated strong, damaging microburst winds which significantly impacted the airport. At 1431MST, the official ASOS wind sensor on the runway complex measured a peak gust to 58 knots. According to city officials, gusty microburst winds estimated to reach as high as 70 mph damaged the roof of terminal 2; the roof damage led to water leakage at three of the gates. Terminals 3 and 4 also suffered roof leaks. Five aircraft at the airport sustained minor damage due to flying debris. Additionally, there was some flooding of local airport roads. The strong gusty winds caused the evacuation of the control tower for approximately one hour, and led to the diversion of 44 inbound flights.

Thunderstorm Wind in MARICOPA, ARIZONA
From 27-SEP-14 14:11:00 to 27-SEP-14 14:11:00 (MST-7)
Location: (LUF)LUKE AFB
Magnitude: 58.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

During the middle of the afternoon on September 27th, a severe squall line moved east across the western portion of the greater Phoenix metropolitan area, and it affected Luke Air Force Base. As the line moved past the base, the official ASOS wind sensor measured a peak gust to 58 knots.