Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 172, NWS Phoenix, AZ

August 13, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Aug 13, 2021, 10:58 PM MST for Maricopa County, Arizona. It was in force for 5 hr. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 13, 2021, 10:58 PM MST (05:58 UTC)
Expired: Aug 14, 2021, 4:00 AM MST
In force: 5 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 69 km from the middle of the area, began a volume at 06:01 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

What was reported inside it

Time	Report	Where	Remark
Aug 13, 11:46 PM MST	FLASH FLOOD	2 Sw Waddell, AZ	CITY OF SURPRISE REPORTS THAT DUE TO FLOODING, COTTON LANE IS CLOSED FROM PEORIA AVENUE TO CACTUS ROAD.
Aug 14, 12:08 AM MST	FLASH FLOOD	3 Nne Beardsley, AZ	CITY OF SURPRISE REPORTS JOMAX RD, 147TH AVE TO CIELO GRAND, IS CLOSED DUE TO FLOODING.
Aug 14, 2:41 AM MST	FLASH FLOOD	1 E Avondale, AZ	CORRECTS PREVIOUS TSTM WND DMG REPORT FROM 1 E AVONDALE. DELAYED REPORT COUNTY FLOOD GAGE AT BUCKEYE RD/AGUA FRIA RIVER EXCEEDED ALARM STAGE (0.72 FT) REACHING 0.79 FT AT 1932 CFS. FLOWING WATER LEAD TO CLOSURE OF LOWER BUCKEYE RD, ONE MILE SOUTH OF THE GA

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Phoenix, AZ (KPSR), launched 00:00Z, 6.0 hours before the alert went out and 37 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1603 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 2033 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 6 m²/s²
0-3 km storm-relative helicity: 78 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

416 
WGUS55 KPSR 140558
FFWPSR
AZC013-141100-
/O.NEW.KPSR.FF.W.0172.210814T0558Z-210814T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1058 PM MST Fri Aug 13 2021

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  Maricopa County in south central Arizona...

* Until 400 AM MST.

* At 1058 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Up to 1 inch of rain has 
  fallen. The expected rainfall rate is 3 inches in 1 hour. 
  Additional rainfall amounts up to 2 inches are possible in the 
  warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life threatening flash flooding. Thunderstorms
           producing flash flooding.

  SOURCE...Radar.

  IMPACT...Life threatening flash flooding of creeks and streams,
           urban areas, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Phoenix, Glendale, Scottsdale, Peoria, Surprise, Avondale, 
  Goodyear, Buckeye, El Mirage, Tolleson, Wickenburg, Youngtown, Sun 
  City West, Wittmann, Waddell, Circle City, Sun City, Cashion, New 
  River and Litchfield Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3328 11220 3326 11220 3321 11225 3322 11247
      3355 11251 3356 11304 3400 11275 3388 11228
      3392 11224 3396 11224 3397 11220 3404 11216
      3381 11189 3382 11210 3380 11225 3332 11215
      3327 11219

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...3 INCHES IN 1 HOUR

$$

Rogers

3 follow-up statements

171 
WGUS75 KPSR 140643
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1143 PM MST Fri Aug 13 2021

AZC013-141100-
/O.CON.KPSR.FF.W.0172.000000T0000Z-210814T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
1143 PM MST Fri Aug 13 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 4 AM MST SATURDAY FOR 
MARICOPA COUNTY...

At 1143 PM MST, Doppler radar indicated thunderstorms producing 
heavy rain across the warned area. Between 1 and 2 inches of rain 
have fallen. The expected rainfall rate is 3 inches in 1 hour. 
Additional rainfall amounts of 0.5 to 1 inch are possible in the 
warned area. Flash flooding is ongoing or expected to begin shortly.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Phoenix, Glendale, Scottsdale, Peoria, Surprise, Avondale, 
  Goodyear, Buckeye, El Mirage, Tolleson, Wickenburg, Youngtown, Sun 
  City West, Wittmann, Waddell, Circle City, Sun City, Cashion, New 
  River and Litchfield Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3328 11220 3326 11220 3321 11225 3323 11248
      3355 11251 3356 11304 3400 11275 3388 11228
      3392 11224 3396 11224 3397 11220 3404 11216
      3381 11189 3382 11210 3380 11225 3332 11215
      3327 11219

FLASH FLOOD...RADAR INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE
EXPECTED RAINFALL...3 INCHES IN 1 HOUR

$$

CK

439 
WGUS75 KPSR 140849
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
149 AM MST Sat Aug 14 2021

AZC013-141100-
/O.CON.KPSR.FF.W.0172.000000T0000Z-210814T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
149 AM MST Sat Aug 14 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 4 AM MST EARLY THIS 
MORNING FOR MARICOPA COUNTY...

At 149 AM MST, Doppler radar and automated rain gauges indicated 
between 1 and 2 inches of rain have fallen. Flash flooding is 
already occurring.

HAZARD...Life threatening flash flooding. Thunderstorms producing
         flash flooding.

SOURCE...Radar and automated gauges.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Phoenix, Glendale, Peoria, Surprise, Avondale, Goodyear, Buckeye, 
  El Mirage, Tolleson, Youngtown, Sun City West, Waddell, Sun City, 
  Wittmann, Cashion, Circle City, New River, Litchfield Park, Cave 
  Creek and Beardsley.

Several road closures have been reported by local officials.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles.

Be especially cautious at night when it is harder to recognize the 
dangers of flooding.

&&

LAT...LON 3326 11220 3321 11225 3325 11245 3355 11251
      3370 11276 3400 11275 3388 11228 3391 11224
      3396 11224 3397 11220 3404 11216 3382 11201
      3380 11225 3332 11215 3328 11220

FLASH FLOOD...RADAR AND GAUGE INDICATED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

Iniguez

263 
WGUS75 KPSR 141056 RRA
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
356 AM MST Sat Aug 14 2021

AZC013-141106-
/O.EXP.KPSR.FF.W.0172.000000T0000Z-210814T1100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
356 AM MST Sat Aug 14 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 4 AM MST EARLY THIS MORNING 
FOR MARICOPA COUNTY...

Flood waters have receded. The heavy rain has ended. Flooding is no 
longer expected to pose a threat. Please continue to heed remaining 
road closures.

A Flash Flood Watch remains in effect until 500 PM MST Sunday for a 
portion of south central Arizona.

LAT...LON 3326 11220 3321 11225 3325 11245 3355 11251
      3370 11276 3400 11275 3388 11228 3391 11224
      3396 11224 3397 11220 3404 11216 3382 11201
      3380 11225 3332 11215 3328 11220

$$

CK

The office that day

Everything else NWS Phoenix, AZ issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 13, 5:14 PM MST	Severe Thunderstorm Warning	PSR	Gila, Maricopa, Pinal	46 min
Aug 13, 5:57 PM MST	Special Weather Statement	PSR	Pinal	48 min
Aug 13, 8:34 PM MST	Special Weather Statement	PSR		41 min
Aug 13, 8:58 PM MST	Special Weather Statement	PSR		47 min
Aug 13, 9:03 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	42 min
Aug 13, 9:19 PM MST	Severe Thunderstorm Warning	PSR	Gila, Maricopa	41 min
Aug 13, 9:38 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	52 min
Aug 13, 9:49 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila, Maricopa	4 hr
Aug 13, 9:54 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	51 min
Aug 13, 9:56 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Aug 13, 9:58 PM MST	Severe Thunderstorm Warning Considerable damage threat	PSR	Gila, Maricopa, Pinal	47 min
Aug 13, 10:02 PM MST	Dust Storm Warning	PSR	La Paz, Maricopa	58 min
Aug 13, 10:05 PM MST	Special Weather Statement	PSR	Pinal	40 min
Aug 13, 10:11 PM MST	Special Weather Statement	PSR	Maricopa	49 min
Aug 13, 10:16 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	44 min
Aug 13, 10:19 PM MST	Flash Flood Warning	PSR	Maricopa	5 hr
Aug 13, 10:24 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Maricopa	36 min
Aug 13, 10:31 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila, Maricopa	4 hr
Aug 13, 10:39 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	4 hr
Aug 13, 10:44 PM MST	Severe Thunderstorm Warning Considerable damage threat	PSR	Gila, Maricopa, Pinal	46 min
Aug 13, 11:01 PM MST	Severe Thunderstorm Warning Considerable damage threat	PSR	La Paz, Maricopa, Yuma	44 min
Aug 13, 11:05 PM MST	Dust Storm Warning	PSR	La Paz, Maricopa, Yuma	55 min
Aug 13, 11:11 PM MST	Special Weather Statement	PSR	Maricopa	49 min
Aug 13, 11:14 PM MST	Flash Flood Warning	PSR	Maricopa, Pinal	5 hr
Aug 13, 11:25 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	65 min
Aug 13, 11:31 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Pinal	5 hr
Aug 13, 11:31 PM MST	Severe Thunderstorm Warning	PSR	Gila	44 min
Aug 13, 11:32 PM MST	Special Weather Statement	PSR	Maricopa	58 min
Aug 13, 11:43 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Maricopa, Yuma	47 min
Aug 13, 11:49 PM MST	Special Weather Statement	PSR	La Paz	41 min
Aug 13, 11:51 PM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz	4 hr
Aug 14, 12:03 AM MST	Dust Storm Advisory	PSR	La Paz, Maricopa, Yuma	57 min
Aug 14, 12:15 AM MST	Special Weather Statement	PSR	Gila	45 min
Aug 14, 12:32 AM MST	Special Weather Statement	PSR	Yuma	43 min
Aug 14, 12:33 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Pinal	4 hr
Aug 14, 12:35 AM MST	Special Weather Statement	PSR	Maricopa	40 min
Aug 14, 12:53 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Aug 14, 1:03 AM MST	Severe Thunderstorm Warning	PSR	Maricopa, Yuma	57 min
Aug 14, 1:04 AM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz, Maricopa, Yuma	4 hr
Aug 14, 1:20 AM MST	Special Weather Statement	PSR	Maricopa	40 min
Aug 14, 1:37 AM MST	Special Weather Statement	PSR	Yuma	38 min
Aug 14, 1:54 AM MST	Dust Storm Warning	PSR	La Paz, Yuma	51 min
Aug 14, 2:26 AM MST	Special Weather Statement	PSR	Yuma	49 min
Aug 14, 3:35 AM MST	Areal Flood Warning	PSR	Maricopa	6 hr
Aug 14, 3:44 AM MST	Areal Flood Warning	PSR	Maricopa	11 hr
Aug 14, 12:17 PM MST	Areal Flood Warning	PSR	Maricopa	6 hr
Aug 14, 1:19 PM MST	Flash Flood Warning Considerable damage threat	PSR	Pinal	4 hr
Aug 14, 2:59 PM MST	Special Weather Statement	PSR	Gila	46 min
Aug 14, 3:26 PM MST	Areal Flood Advisory	PSR	Gila	3 hr
Aug 14, 4:55 PM MST	Special Weather Statement	PSR	Gila	50 min

Nearby

Flash Flood Warnings in Arizona, 2021 Every flash flood warning in 2021

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.