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Damaging Thunderstorms and a Squall Line Impact
Central Arizona Including Phoenix Metro Area


Updated: 1pm Mon Sep 29 2014

 

Sky Harbor Gate Damage

Damage to Sky Harbor tarmac and gates at several terminals. Image courtesy dexterdunning via Twitter.

A strong upper level Pacific cold front was moving southward through the Southwest states late in the week. This cut-off Low pressure system carried a good amount of upper level support and wind dynamics as well as instability ahead of the front to support severe convective weather. Precipitable water values over 1.25 inches was in place, as was a Monsoon wind pattern, with winds out of the south-southeast. As the weather system approached, wind shear throughout the region was gaining strength and ingredients were lining up for the event to become quite severe. A transitional event like this, where the warm temperatures are slowly changing to a cooler air-mass and the wind begins to shift from southerly to more west-northwesterly can create strong thunderstorms. Similar to the October 5th, 2010 event in set up with subtle differences in moisture values and the Low pressure placement, this event was severe in many ways.

Strong storms began to form in the far Western portions of Arizona by mid-morning on Saturday September 27th. Around 12 pm a line of thunderstorms began to form just southwest of Buckeye. These thunderstorms were moving quite fast, 35-45 mph and were capable of producing heavy rain, as can be seen in rainfall accumulation maps. The wind might be one of the more notable impacts from this event. Area-wide damage was seen from power poles snapping and falling over to downed trees and numerous pieces of roofing that was torn off. One of many high wind reports, Sky Harbor reported 67 mph wind gust (58 kts) which led to substantial damage to a few terminals as well as impacted over 40 flights which had to be diverted.

 

 

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Satellite loop
KIWA Radar loop

Infrared satellite image showing the evolution of storms Saturday afternoon and evening over the Central Arizona deserts and the Phoenix area on September 27, 2014. Loop is from 11 AM to 5 PM Sunday. (Loop is 5MB)

Radar loop from 12:32 PM to 4:45 PM Saturday showing the progression and evolution of the line of thunderstorms that approach Phoenix from the west and plowed eastward. (Loop is 10MB)

 

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KIWA Velocity Radar loop
Monsoon Rain Totals

Phoenix KIWA Doppler Radar loop of wind velocity across the Phoenix metro. (Loop is 9MB)

Monsoon Rainfall Totals for our Climate Stations. Updated through September 28th.

Phoenix Sky Harbor airport had yet another record breaking rainfall event. The previous daily record rainfall of 1.46 inches set back in 1903 was shattered when Sky Harbor picked up 1.64 inches of rain (an additional 0.02 inches just after midnight rose the event total to 1.66 inches) for September 27th.

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NWSPhoenix twitter record
Precip analysis
Precip analysis

NWS Phoenix on Twitter, breaking the daily record rainfall amount at Sky Harbor.

Rain gauge analysis showing rainfall totals across the metro area.

1 day Rain gauge totals courtesy of Flood Control District of Maricopa Co.


Flooding and damage photos across the region
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Phoenix Tree Damage
Fairgrounds Flooding
Durango Curve Flooding

Large tree down at 59th Ave & Indian School Rd. Image courtesy David Wallace, AZ Republic

Arizona State Fair Grounds flooding. Image courtesy Bill Friar via Twitter

Interstate 17 flooded at the Durango Curve. Image courtesy David Wallace, AZ Republic

Sky Harbor damage
Sky Harbor damage
Sky Harbor damage

Damage at Sky Harbor Airport. Image courtesy Adam Longo, CBS5 via Twitter

Damage at Sky Harbor Airport. Image courtesy Michael Meister, AZ Republic via Twitter

Damage at Sky Harbor Airport. Image courtesy Adam Longo, CBS5 via Twitter

Tree damage
Power pole damage
Power pole damage

Uprooted tree in Phoenix. Image courtesy Dominic valente, AZ Republic

Powerpole damage at 59th Ave & Greenway. Image courtesy Lauren, ABC15 via Twitter

Powerpole damage in Phoenix. Image courtesy 12News via Twitter


Storm Reports
 PRELIMINARY LOCAL STORM REPORT...SUMMARY
 NATIONAL WEATHER SERVICE PHOENIX AZ
 1022 PM MST SAT SEP 27 2014
 
 ..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
 ..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
             ..REMARKS..
 
 0715 AM     FLOOD            2 NW BUCKSKIN MOUNTAIN  34.25N 114.17W
 09/27/2014                   LA PAZ             AZ   BROADCAST MEDIA 
 
             0.55 INCH OF RAIN IN 25 MIINUTES WITH STREET FLODDING 
 
 0715 AM     HEAVY RAIN       2 NW BUCKSKIN MOUNTAIN  34.25N 114.17W
 09/27/2014  M0.55 INCH       LA PAZ             AZ   BROADCAST MEDIA 
 
             0.55 INCH OF RAIN IN 25 MIINUTES WITH STREET FLODDING 
 
 0146 PM     HEAVY RAIN       2 W PERRYVILLE          33.43N 112.53W
 09/27/2014  M0.71 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             HEAVY RAIN MEASURED IN 30 MIN 
 
 0200 PM     HEAVY RAIN       2 NNW GOODYEAR          33.44N 112.41W
 09/27/2014  M0.80 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             0.80 INCH OF RAIN IN 30 MINUTES. 
 
 0201 PM     TSTM WND GST     2 NW PERRYVILLE         33.45N 112.53W
 09/27/2014  E50 MPH          MARICOPA           AZ   TRAINED SPOTTER 
 
             VISIBILITY DOWN TO LESS THAN 1 2 MILE 
 
 0201 PM     HEAVY RAIN       2 NW PERRYVILLE         33.45N 112.53W
 09/27/2014  M0.30 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             VISIBILITY DOWN TO LESS THAN 1 2 MILE 
 
 0210 PM     TSTM WND DMG     4 N GLENDALE            33.60N 112.19W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             50 MPH. STREET FLOODING. 1.5 INCHES MEASURED IN 30 MIN. 
             ROOF DAMAGE. AWNING BLOWN APART FROM TRAILER PARK. POWER 
             OUTAGE AS WELL. 
 
 0211 PM     TSTM WND GST     1 NNW LUKE AFB          33.54N 112.38W
 09/27/2014  M67 MPH          MARICOPA           AZ   ASOS            
 
 0218 PM     TSTM WND DMG     4 WNW METRO CENTER      33.61N 112.19W
 09/27/2014                   MARICOPA           AZ   BROADCAST MEDIA 
 
             POWER POLE FELL AND BLOCKED ROADWAY... FELL ON CAR. 
 
 0228 PM     TSTM WND GST     9 E PEORIA              33.69N 112.08W
 09/27/2014  M71 MPH          MARICOPA           AZ   ASOS            
 
 0231 PM     TSTM WND GST     6 NNW GUADALUPE         33.43N 112.01W
 09/27/2014  M67 MPH          MARICOPA           AZ   ASOS            
 
 0231 PM     TSTM WND DMG     2 NE DOWNTOWN PHOENIX   33.47N 112.06W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             12 INCH DIAMTER TREE TORN DOWN IN PARKING LOT OF 
             HOSPITAL. 
 
 0234 PM     HAIL             7 SW FIREBIRD LAKE      33.21N 112.06W
 09/27/2014  M0.50 INCH       PINAL              AZ   TRAINED SPOTTER 
 
             CORRECTED REPORT...HALF INCH HAIL... 0.35 INCH RAIN IN 
             30 MIN... WINDS 40 MPH. 
 
 0235 PM     HEAVY RAIN       3 S PIESTEWA PEAK PARK  33.50N 112.03W
 09/27/2014  M0.71 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             MEASURED RAIN IN 20 MIN. 
 
 0237 PM     TSTM WND GST     1 E TUMBLEWEED PARK     33.27N 111.81W
 09/27/2014  M58 MPH          MARICOPA           AZ   ASOS            
 
 0240 PM     FLOOD            2 SSE GLENDALE          33.52N 112.18W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             FLOODED ROADWAY COVERING WHEEL WELLS OF VEHICLES. POWER 
             OUTAGE TO LOCAL BUSINESS. 
 
 0240 PM     TSTM WND DMG     SKY HARBOR AIRPORT      33.44N 112.01W
 09/27/2014                   MARICOPA           AZ   CITY OFFICIAL   
 
             PHOENIX SKY HARBOR AIRPORT SUSTAINED ROOF DAMAGE AT 
             TERMINAL 2 AND WATER LEAKAGE OCCURRED AT THREE OF THE 
             GATES. TERMINAL 3 AND 4 ALSO HAVE ROOF LEAKS. FIVE 
             AIRCRAFT SUSTAINED MINOR DAMAGE DUE TO FLYING DEBRIS. 
             SOME FLOODING OF AIRPORT ROADS. FORTY-FOUR FLIGHTS 
             DIVERTED. 
 
 0245 PM     TSTM WND DMG     3 NNE NORTH MOUNTAIN PA 33.63N 112.05W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             8 INCH DIAMETER TREE DOWN... 50 PLUS MPH WIND GUSTS... 
             FLOODED ROAD 2-3 INCH DEEP 
 
 0245 PM     HEAVY RAIN       3 ENE GILBERT           33.35N 111.72W
 09/27/2014  M0.50 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             MEASURED IN 15 MINUTES. 
 
 0250 PM     TSTM WND DMG     2 SW PAPAGO PARK        33.44N 111.98W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             FREEWAY SIGNS DOWN ON 143 SALT RIVER BRIDGE 
 
 0255 PM     FLOOD            2 ESE DOWNTOWN SCOTTSDA 33.48N 111.89W
 09/27/2014                   MARICOPA           AZ   AMATEUR RADIO   
 
             CURB-TO-CURB STREET FLOODING AT PIMA AND THOMAS 4 DIA 
             TREE BRANCH. 
 
 0300 PM     HEAVY RAIN       2 WSW FOUNTAIN HILLS    33.59N 111.77W
 09/27/2014  M0.75 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             MEASURED IN 20 MINUTES. MEASURED 42 MPH WIND. 
 
 0311 PM     TSTM WND DMG     2 ESE DOWNTOWN SCOTTSDA 33.48N 111.89W
 09/27/2014                   MARICOPA           AZ   AMATEUR RADIO   
 
             SEVERAL DOWNED TREES NEAR THOMAS PIMA ROADS. 
 
 0311 PM     FLOOD            1 WNW ARIZONA STATE FAI 33.48N 112.11W
 09/27/2014                   MARICOPA           AZ   BROADCAST MEDIA 
 
             FLOODED UNDERPASS AT I-17 AND GRANT ROAD. INTERSTATE IS 
             IMPASSABLE 
 
 0317 PM     FLOOD            4 S GOLDFIELD RANCH     33.54N 111.61W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             FLOODED ROADS AND SOME ARE UNPASSABLE 
 
 0331 PM     HEAVY RAIN       8 SSW AK-CHIN VILLAGE   32.93N 112.16W
 09/27/2014  M0.84 INCH       PINAL              AZ   TRAINED SPOTTER 
 
             MEASURED IN 30 MIN AND STILL FALLING. FLOODED ROADWAYS 
 
 0331 PM     FLOOD            1 NNE METRO CENTER      33.60N 112.12W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             3 TO 4 FOOT OF WATER ACCUMULATED UNDER UNDERPASS OF 
             I-17 
 
 0332 PM     FLOOD            2 NNE DOWNTOWN SCOTTSDA 33.52N 111.90W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             CURB TO CURB FLOODING WITH AREAS UNPASSABLE. MORE THAN 
             15 TREE LIMBS TORN DOWN. SIZE UNKNOWN 
 
 0339 PM     TSTM WND DMG     2 ESE FALCON FIELD AIRP 33.45N 111.68W
 09/27/2014                   MARICOPA           AZ   NWS EMPLOYEE    
 
             2 FOOT DIAMETER TREE DOWN... BLOCKING ROADWAY. 
 
 0346 PM     TSTM WND GST     3 NNW GLENDALE          33.58N 112.20W
 09/27/2014  M75 MPH          MARICOPA           AZ   TRAINED SPOTTER 
 
             ROOF TILES PEELED OFF FROM WIND. 
 
 0401 PM     FLOOD            GOODYEAR                33.42N 112.40W
 09/27/2014                   MARICOPA           AZ   BROADCAST MEDIA 
 
             FLOODED NEIGHBORHOOD AND ROADS NEAR 156 AVENUE AND WEST 
             INDIAN SCHOOL ROAD 
 
 0408 PM     FLASH FLOOD      1 SE DOWNTOWN SCOTTSDAL 33.49N 111.91W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             INDIAN BEND WASH FLOWING AT LEAST 2 FEET DEEP OVER 
             OSBORN RD. MILLER RD FROM 2ND ST TO OSBORN HAS WATER TO 
             TOP OF CURB. 
 
 0416 PM     HEAVY RAIN       2 ESE SAN TAN MOUNTAIN  33.14N 111.62W
 09/27/2014  M0.57 INCH       PINAL              AZ   TRAINED SPOTTER 
 
             MEASURED IN 10 MIN. WASHES RUNNING 4 INCHES DEEP 
 
 0425 PM     FLOOD            3 NNW SKY HARBOR AIRPOR 33.48N 112.03W
 09/27/2014                   MARICOPA           AZ   TRAINED SPOTTER 
 
             24TH STREET AND THOMAS... ROAD FLOODED AND UNPASSABLE. 
 
 0433 PM     HEAVY RAIN       2 ESE SAN TAN MOUNTAIN  33.14N 111.62W
 09/27/2014  M1.05 INCH       PINAL              AZ   TRAINED SPOTTER 
 
             MEASURED IN 30 MIN. THIS AMOUNT IS DIFFERENT THAN 
             PREVIOUS AMOUNT FROM SAME LOCATION. 
 
 0437 PM     TSTM WND DMG     1 WNW SAN TAN VALLEY    33.18N 111.58W
 09/27/2014                   PINAL              AZ   TRAINED SPOTTER 
 
             FIVE 12-14 INCH DIAMTER TREES BLOWN DOWN 
 
 0439 PM     HEAVY RAIN       1 N SAN TAN VALLEY      33.19N 111.57W
 09/27/2014  M1.00 INCH       PINAL              AZ   TRAINED SPOTTER 
 
             SPOTTER MEASURED 1.00 INCH OF RAIN BETWEEN 4...10 PM 
             AND 4...39 PM. STREET FLOODING WITH WATER NEAR TOP OF 
             CURB. 
 
 0520 PM     HEAVY RAIN       3 SE TEMPE              33.36N 111.90W
 09/27/2014  M2.14 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             STORM TOTAL RAIN OVER LAST FEW HOURS 
 
 0528 PM     HEAVY RAIN       2 WSW FOUNTAIN HILLS    33.59N 111.78W
 09/27/2014  M2.14 INCH       MARICOPA           AZ   TRAINED SPOTTER 
 
             STORM TOTAL RAIN MEAUSRED OVER 3 HOURS. 
 
 0803 PM     FLOOD            2 NE APACHE JUNCTION    33.43N 111.52W
 09/27/2014                   PINAL              AZ   DEPT OF HIGHWAYS
 
             STATE ROUTE 88 CLOSED FROM MP 200 TO MP 202 DUE TO 
             FLOODING 
 
 
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