Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 28, NWS Phoenix, AZ

July 9, 2021Maricopa County, Pinal County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 9, 2021, 11:33 PM MST for Maricopa County, Pinal County, Arizona. It was in force for 4 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: Jul 9, 2021, 11:33 PM MST (06:33 UTC)
Expired: Jul 10, 2021, 3:30 AM MST
In force: 4 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Maricopa County, AZ, Pinal County, AZ

The radar

The Phoenix radar (KIWA), 68 km from the middle of the area, began a volume at 06:33 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 10, 3:30 AM MST	FLASH FLOOD	11 Wsw Mobile, AZ	CORRECTS PREVIOUS FLASH FLOOD REPORT FROM 11 WSW MOBILE FOR DATE FROM JULY 9TH TO 10TH. *DELAYED REPORT*ROAD CLOSURE REQUESTED FOR EASTBOUND AND WESTBOUND HIGHWAY 238; COMPLETED BETWEEN 4-4:30 A.M. WITH NO UPDATE OF REOPENING BY 7:20 A.M.

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, 6.6 hours before the alert went out and 58 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: 1011 J/kg
Mixed-layer CIN: -182 J/kg
Mixed-layer LCL: 3280 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: -35 m²/s²
0-3 km storm-relative helicity: 54 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.1

Open this sounding in Storm Lab

The text

As transmitted.

864 
WGUS55 KPSR 100633
FFWPSR
AZC013-021-101030-
/O.NEW.KPSR.FF.W.0028.210710T0633Z-210710T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1133 PM MST Fri Jul 9 2021

The National Weather Service in Phoenix has issued a

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

* Until 330 AM MST.

* At 1133 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 0.5 and 1.5 inches of 
  rain have fallen. Additional rainfall amounts up 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...
  Gila Bend, Maricopa, Estrella, Sonoran National Monument, Bosque, 
  Mobile and Ak-Chin Village.

This includes the following highways...
	AZ Route 238 between Gila Bend and Maricopa.
	AZ Route 347 between mile markers 169 and 174.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3298 11266 3300 11257 3305 11254 3305 11239
      3309 11222 3307 11213 3307 11195 3306 11193
      3304 11193 3300 11196 3299 11200 3297 11220
      3293 11224 3293 11236 3290 11237 3291 11252
      3293 11265 3295 11269

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

$$

Iniguez

2 follow-up statements

952 
WGUS75 KPSR 100742
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1242 AM MST Sat Jul 10 2021

AZC013-021-101030-
/O.CON.KPSR.FF.W.0028.000000T0000Z-210710T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-Pinal AZ-
1242 AM MST Sat Jul 10 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 330 AM MST EARLY THIS 
MORNING FOR MARICOPA AND PINAL COUNTIES...

At 1242 AM MST, Doppler radar indicated thunderstorms produced heavy 
rain up to 1.5 inches. 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...
  Gila Bend, Maricopa, Estrella, Sonoran National Monument, Bosque, 
  Mobile and Ak-Chin Village.

This includes the following highways...
	AZ Route 238 between Maricopa and Gila Bend.
	AZ Route 347 between mile markers 169 and 174.

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.

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3298 11266 3300 11257 3305 11254 3305 11239
      3309 11222 3307 11213 3307 11195 3306 11193
      3304 11193 3300 11196 3299 11200 3297 11220
      3293 11224 3293 11236 3290 11237 3291 11252
      3293 11265 3295 11269

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

$$

Iniguez

411 
WGUS75 KPSR 101022
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
322 AM MST Sat Jul 10 2021

AZC013-021-101032-
/O.EXP.KPSR.FF.W.0028.000000T0000Z-210710T1030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-Pinal AZ-
322 AM MST Sat Jul 10 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 330 AM MST EARLY THIS MORNING 
FOR MARICOPA AND PINAL COUNTIES...

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.

LAT...LON 3298 11266 3300 11257 3305 11254 3305 11239
      3309 11222 3307 11213 3307 11195 3306 11193
      3304 11193 3300 11196 3299 11200 3297 11220
      3293 11224 3293 11236 3290 11237 3291 11252
      3293 11265 3295 11269

$$

Iniguez

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 5:36 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	6 hr
Jul 9, 5:36 PM MST	Special Weather Statement	PSR	Gila	24 min
Jul 9, 6:23 PM MST	Special Weather Statement	PSR		52 min
Jul 9, 7:45 PM MST	Special Weather Statement	PSR		30 min
Jul 9, 8:15 PM MST	Severe Thunderstorm Warning	PSR	Gila	45 min
Jul 9, 8:58 PM MST	Severe Thunderstorm Warning	PSR	Gila, Maricopa, Pinal	47 min
Jul 9, 9:18 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	4 hr
Jul 9, 9:18 PM MST	Special Weather Statement	PSR	Pinal	42 min
Jul 9, 9:32 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila, Pinal	4 hr
Jul 9, 9:39 PM MST	Severe Thunderstorm Warning	PSR	Gila, Maricopa, Pinal	36 min
Jul 9, 9:54 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	51 min
Jul 9, 10:06 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	39 min
Jul 9, 10:21 PM MST	Dust Storm Warning	PSR	Maricopa, Pinal	54 min
Jul 9, 10:30 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	45 min
Jul 9, 10:32 PM MST	Flash Flood Warning Considerable damage threat	PSR	Pinal	4 hr
Jul 9, 10:44 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	31 min
Jul 9, 10:52 PM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Jul 9, 11:12 PM MST	Dust Storm Advisory	PSR	Maricopa	63 min
Jul 9, 11:15 PM MST	Dust Storm Warning	PSR	Maricopa, Pinal	60 min
Jul 9, 11:19 PM MST	Severe Thunderstorm Warning	PSR	Pinal	26 min
Jul 9, 11:22 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	38 min
Jul 9, 11:31 PM MST	Dust Storm Advisory	PSR	Maricopa	44 min
Jul 10, 1:02 AM MST	Special Weather Statement	PSR	Yuma	28 min
Jul 10, 1:57 PM MST	Blowing Dust Advisory	PSR	Maricopa, Pinal	9 hr
Jul 10, 2:27 PM MST	Special Weather Statement	PSR	Gila	48 min
Jul 10, 3:15 PM MST	Special Weather Statement	PSR	Gila	45 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.