Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 239, NWS Phoenix, AZ

August 31, 2021La Paz County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Aug 31, 2021, 10:36 PM MST for La Paz County, Arizona. It was in force for 6 hr. 1 report 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 31, 2021, 10:36 PM MST (05:36 UTC)
Expired: Sep 1, 2021, 4:30 AM MST
In force: 6 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County La Paz County, AZ

The radar

The Phoenix radar (KIWA), 196 km from the middle of the area, began a volume at 05:37 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 31, 11:44 PM MST	HEAVY RAIN 1.93	Wenden, AZ	A MARICOPA COUNTY FLOOD CONTROL DISTRICT GAUGE ALONG HIGHWAY 60 AT THE CENTENNIAL WASH MEASURED 1.93 INCHES IN ABOUT 1 HOUR AND 20 MINUTES AS OF 1144PM. THE HEAVIEST 1 HOUR AMOUNT WAS 1.81 INCHES BETWEEN 1028PM AND 1128PM.

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, 5.6 hours before the alert went out and 164 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: 70 J/kg
Mixed-layer CIN: -132 J/kg
Mixed-layer LCL: 1562 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: -43 m²/s²
0-3 km storm-relative helicity: 95 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

891 
WGUS55 KPSR 010536
FFWPSR
AZC012-011130-
/O.NEW.KPSR.FF.W.0239.210901T0536Z-210901T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1036 PM MST Tue Aug 31 2021

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  Northeastern La Paz County in west central Arizona...

* Until 430 AM MST.

* At 1036 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across eastern La Paz County. This will impact the 
  Centennial Wash, including Wenden and Salome. Up to 1 inch of rain 
  has fallen. Additional rainfall amounts of 1 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...
  Wenden, Salome, Harcuvar and Alamo Lake State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3351 11333 3361 11350 3373 11368 3398 11383
      3422 11372 3421 11370 3421 11368 3422 11365
      3423 11364 3423 11361 3424 11359 3426 11358
      3429 11355 3430 11354 3431 11353 3429 11341
      3430 11340 3429 11337 3430 11335 3432 11334

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

$$

CK

2 follow-up statements

208 
WGUS75 KPSR 010627
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1127 PM MST Tue Aug 31 2021

AZC012-011130-
/O.CON.KPSR.FF.W.0239.000000T0000Z-210901T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
La Paz AZ-
1127 PM MST Tue Aug 31 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 AM MST WEDNESDAY 
FOR NORTHEASTERN LA PAZ COUNTY...

At 1127 PM MST, Doppler radar indicated thunderstorms producing 
heavy rain within the Centennial Wash impacting Wenden and Salome, 
along with rain within the Cunningham Wash. Between 0.5 and 2 inches 
of rain have fallen with 1.6 inches measured in Wenden in the past 
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...
  Wenden, Salome, Harcuvar and Alamo Lake State Park.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3351 11333 3361 11350 3373 11368 3398 11383
      3422 11372 3421 11370 3421 11368 3422 11365
      3423 11364 3423 11361 3424 11359 3426 11358
      3429 11355 3430 11354 3431 11353 3429 11341
      3430 11340 3429 11337 3430 11335 3432 11334

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

$$

CK

936 
WGUS75 KPSR 011121
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
421 AM MST Wed Sep 1 2021

AZC012-011131-
/O.EXP.KPSR.FF.W.0239.000000T0000Z-210901T1130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
La Paz AZ-
421 AM MST Wed Sep 1 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 430 AM MST EARLY THIS MORNING 
FOR NORTHEASTERN LA PAZ COUNTY...

Flood waters have receded. 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 AM MST Thursday for 
portions of south central Arizona and southwest Arizona.

LAT...LON 3351 11333 3361 11350 3373 11368 3398 11383
      3422 11372 3421 11370 3421 11368 3422 11365
      3423 11364 3423 11361 3424 11359 3426 11358
      3429 11355 3430 11354 3431 11353 3429 11341
      3430 11340 3429 11337 3430 11335 3432 11334

$$

Iniguez

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 1, 12:02 AM MST	Areal Flood Advisory	PSR	Maricopa	3 hr
Sep 1, 1:07 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	5 hr
Sep 1, 6:44 AM MST	Areal Flood Warning	PSR	Gila	5 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.