Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 75, NWS Phoenix, AZ

July 25, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 25, 2021, 8:51 AM MST for Maricopa County, Arizona. It was in force for 6 hr. 2 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, 8:51 AM MST (15:51 UTC)
Expired: Jul 25, 2021, 3:00 PM MST
In force: 6 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), 78 km from the middle of the area, began a volume at 15:50 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, 9:00 AM MST	FLASH FLOOD	1 Nw Waddell, AZ	REPORT OF 4-6 INCHES OF RUNNING WATER OVER THE ROAD NEAR LEGACY PARC BLVD AND MAUNA LOA LN.
Jul 25, 11:40 AM MST	FLASH FLOOD	Buckeye, AZ	SEVERAL ROAD CLOSURES IN BUCKEYE, INCLUDING DEAN AND BROADWAY, LOWER BUCKEYE BETWEEN WATSON AND RAINBOW, VERRADO AND BROADWAY, VERRADO AND YUMA.

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

The nearest sounding before it

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 3.9 hours before the alert went out and 202 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: 4 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 803 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: -30 m²/s²
0-3 km storm-relative helicity: 25 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

745 
WGUS55 KPSR 251551
FFWPSR
AZC013-252000-
/O.NEW.KPSR.FF.W.0075.210725T1551Z-210725T2000Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
851 AM 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 100 PM MST.

* At 851 AM MST, Doppler radar and automated rain gauges indicated 
  heavy rain falling across the warned area. Between 1 and 2 inches 
  of rain have fallen. Additional rainfall amounts of 0.5 to 1.5 
  inches are possible in the warned area. Flash flooding is ongoing 
  or expected to begin shortly.

  HAZARD...Life threatening flash flooding. Heavy rain 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, Surprise, Avondale, Goodyear, Buckeye, El 
  Mirage, Youngtown, Waddell, Cashion, Sun City, Litchfield Park, 
  White Tank Mountain Park, Perryville, Luke AFB, Liberty and 
  Surprise Stadium.

This includes the following highways...
	AZ Interstate 10 between mile markers 112 and 121.
	AZ Route 303 between mile markers 105 and 114.
	AZ Route 85 between mile markers 150 and 154.

This includes the following streams and drainages...
  Wagner Wash, Agua Fria River, Trilby Wash, Lum Wash, Beardsley 
  Canal, Gila River, Corgett Wash and Hassayampa River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3337 11232 3336 11245 3336 11265 3341 11265
      3363 11265 3373 11261 3371 11245 3359 11230
      3349 11231

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

$$

SDB

2 follow-up statements

571 
WGUS55 KPSR 251952
FFWPSR
AZC013-252200-
/O.EXT.KPSR.FF.W.0075.000000T0000Z-210725T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1252 PM MST Sun Jul 25 2021

The National Weather Service in Phoenix has extended the

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

* Until 300 PM MST.

* At 1252 PM MST, trained weather spotters reported heavy rain and 
  washes flowing across the warned area. Between 1 and 2 inches of 
  rain have fallen. Additional rainfall amounts of 0.5 are possible 
  in the warned area. Flash flooding is ongoing or expected to begin 
  shortly.

  HAZARD...Life threatening flash flooding. Heavy rain producing
           flash flooding.

  SOURCE...Trained spotters reported.

  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, Surprise, Avondale, Goodyear, Buckeye, El 
  Mirage, Youngtown, Waddell, Cashion, Sun City, Litchfield Park, 
  White Tank Mountain Park, Perryville, Luke AFB, Liberty and 
  Surprise Stadium.

This includes the following highways...
	AZ Interstate 10 between mile markers 112 and 121.
	AZ Route 303 between mile markers 105 and 114.
	AZ Route 85 between mile markers 150 and 154.

This includes the following streams and drainages...
  Wagner Wash, Agua Fria River, Trilby Wash, Lum Wash, Beardsley 
  Canal, Gila River, Corgett Wash and Hassayampa River.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3337 11232 3336 11245 3336 11265 3341 11265
      3363 11265 3373 11261 3371 11245 3359 11230
      3349 11231

FLASH FLOOD...OBSERVED
FLASH FLOOD DAMAGE THREAT...CONSIDERABLE

$$

MS

609 
WGUS75 KPSR 252158
FFSPSR

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

AZC013-252208-
/O.EXP.KPSR.FF.W.0075.000000T0000Z-210725T2200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
258 PM MST Sun Jul 25 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 3 PM MST THIS AFTERNOON FOR 
MARICOPA COUNTY...

The heavy rain has ended along the Loop 303 corridor. 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 11232 3336 11245 3336 11265 3341 11265
      3363 11265 3373 11261 3371 11245 3359 11230
      3349 11231

$$

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, 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, 12:35 PM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	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.