Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 83, NWS Phoenix, AZ

July 25, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 25, 2021, 12:35 PM MST for Maricopa County, Arizona. It was in force for 4 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: Jul 25, 2021, 12:35 PM MST (19:35 UTC)
Expired: Jul 25, 2021, 4:45 PM MST
In force: 4 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), 70 km from the middle of the area, began a volume at 19:36 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
Jul 25, 1:10 PM MST	FLASH FLOOD	9 Se Buckeye, AZ	DELAYED REPORT. A STREAM GAUGE AT WATERMAN WASH REACHED ALARM STAGE AND CONTINUED TO RISE AFTER THAT. THIS MADE DOWNSTREAM ROAD CROSSINGS, INCLUDING SOUTH TUTHILL ROAD, IMPASSABLE.
Jul 25, 1:30 PM MST	FLASH FLOOD	7 Se Buckeye, AZ	ROAD CLOSED DUE TO FLOODING. SOCIAL MEDIA VIDEOS SHOW WELL OVER 6 INCHES OF SWIFT MOVING WATER OVER THE ROAD.
Jul 25, 3:00 PM MST	FLASH FLOOD	6 Ese Buckeye, AZ	ROAD CLOSED DUE TO FLOODING. SOCIAL MEDIA VIDEOS SHOW WELL OVER 6 INCHES OF SWIFT MOVING WATER OVER THE ROAD.

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

The nearest sounding before it

Tuscon, AZ (KTUS), launched 12:00Z, 7.6 hours before the alert went out and 191 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: 151 J/kg
Mixed-layer CIN: -3 J/kg
Mixed-layer LCL: 521 m above ground
0-6 km bulk shear: 5 kt
0-1 km storm-relative helicity: 95 m²/s²
0-3 km storm-relative helicity: 103 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

482 
WGUS55 KPSR 251935
FFWPSR
AZC013-252345-
/O.NEW.KPSR.FF.W.0083.210725T1935Z-210725T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1235 PM MST Sun Jul 25 2021

The National Weather Service in Phoenix has issued a

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

* Until 445 PM MST.

* At 1235 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain in Waterman Wash. Between 0.5 
  and 1.5 inches of rain have fallen. Water rise in Waterman Wash is 
  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...
  Avondale, Goodyear, Buckeye, Estrella Mountain Ranch and Estrella 
  Mountain Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3337 11235 3334 11233 3330 11236 3325 11247
      3329 11253 3336 11253

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

$$

MS

2 follow-up statements

356 
WGUS75 KPSR 252249
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
349 PM MST Sun Jul 25 2021

AZC013-252345-
/O.CON.KPSR.FF.W.0083.000000T0000Z-210725T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
349 PM MST Sun Jul 25 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM MST THIS 
AFTERNOON FOR MARICOPA COUNTY...

At 349 PM MST, automated stream gauges indicated a rapid rise above 
alarm stage along Waterman Wash. The wash continues to be elevated 
and impact road crossings.

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...
  Avondale, Goodyear, Buckeye, Estrella Mountain Ranch and Estrella 
  Mountain Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3337 11235 3334 11233 3330 11236 3325 11247
      3329 11253 3336 11253

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

$$

MS

031 
WGUS75 KPSR 252341
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
441 PM MST Sun Jul 25 2021

AZC013-252351-
/O.EXP.KPSR.FF.W.0083.000000T0000Z-210725T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
441 PM MST Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 445 PM MST THIS AFTERNOON FOR 
MARICOPA COUNTY...

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 1200 AM MST Monday for a 
portion of south central Arizona.

LAT...LON 3337 11235 3334 11233 3330 11236 3325 11247
      3329 11253 3336 11253

$$

Iniguez

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 24, 10:57 PM MST	Areal Flood Advisory	PSR	Maricopa	5 hr
Jul 25, 4:45 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Jul 25, 6:27 AM MST	Areal Flood Advisory	PSR	Pinal	3 hr
Jul 25, 7:14 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Jul 25, 7:38 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Jul 25, 7:57 AM MST	Areal Flood Advisory	PSR	Pinal	3 hr
Jul 25, 8:01 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Jul 25, 8:45 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Pinal	4 hr
Jul 25, 8:51 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	6 hr
Jul 25, 9:00 AM MST	Flash Flood Warning Considerable damage threat	PSR	Pinal	4 hr
Jul 25, 9:39 AM MST	Areal Flood Advisory	PSR	Maricopa	17 min
Jul 25, 9:47 AM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Jul 25, 9:56 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	8 hr
Jul 25, 10:08 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa, Pinal	4 hr
Jul 25, 10:16 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Jul 25, 10:41 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Jul 25, 12:11 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	4 hr
Jul 25, 12:54 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Jul 25, 2:10 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila, Maricopa	4 hr
Jul 25, 2:14 PM MST	Flash Flood Warning	PSR	Maricopa	3 hr
Jul 25, 2:18 PM MST	Flash Flood Warning	PSR	Maricopa	3 hr
Jul 25, 3:29 PM MST	Special Weather Statement	PSR	La Paz	31 min
Jul 25, 4:02 PM MST	Flash Flood Warning Considerable damage threat	PSR	La Paz	4 hr

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.