Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 31, NWS Phoenix, AZ

July 12, 2021Gila County, Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 12, 2021, 10:14 PM MST for Gila County, Maricopa County, Arizona. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 12, 2021, 10:14 PM MST (05:14 UTC)
Expired: Jul 13, 2021, 12:15 AM MST
In force: 2 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

Counties Gila County, AZ, Maricopa County, AZ

The radar

The Phoenix radar (KIWA), 66 km from the middle of the area, began a volume at 05:17 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.

The nearest sounding before it

Phoenix, AZ (KPSR), launched 00:00Z, 5.2 hours before the alert went out and 59 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: 523 J/kg
Mixed-layer CIN: -351 J/kg
Mixed-layer LCL: 2953 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: 38 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

162 
WGUS55 KPSR 130514
FFWPSR
AZC007-013-130715-
/O.NEW.KPSR.FF.W.0031.210713T0514Z-210713T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
1014 PM MST Mon Jul 12 2021

The National Weather Service in Phoenix has issued a

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

* Until 1215 AM MST.

* At 1014 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  1 and 2 inches of rain have fallen. Flash flooding is ongoing or 
  expected to begin shortly.

  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, Scottsdale and Carefree.

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.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3400 11149 3401 11150 3401 11143 3399 11142
      3393 11151 3387 11158 3378 11167 3371 11187
      3367 11190 3369 11198 3373 11198 3400 11165
      3400 11150

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

$$

JS

2 follow-up statements

548 
WGUS75 KPSR 130540
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1040 PM MST Mon Jul 12 2021

AZC007-013-130715-
/O.CON.KPSR.FF.W.0031.000000T0000Z-210713T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Maricopa AZ-
1040 PM MST Mon Jul 12 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1215 AM MST TUESDAY 
FOR GILA AND MARICOPA COUNTIES...

At 1040 PM MST, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain across the warned area. Between 1 
and 2 inches of rain have fallen. Flash flooding is ongoing.

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...
north Phoenix, Scottsdale and Carefree.

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.

Be aware of your surroundings and do not drive on flooded roads.

&&

LAT...LON 3400 11149 3401 11150 3401 11143 3399 11142
      3393 11151 3387 11158 3378 11167 3371 11187
      3367 11190 3369 11198 3373 11198 3400 11165
      3400 11150

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

$$

JS

161 
WGUS75 KPSR 130711
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1211 AM MST Tue Jul 13 2021

AZC007-013-130721-
/O.EXP.KPSR.FF.W.0031.000000T0000Z-210713T0715Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Gila AZ-Maricopa AZ-
1211 AM MST Tue Jul 13 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1215 AM MST EARLY THIS MORNING 
FOR GILA AND MARICOPA 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 3400 11149 3401 11150 3401 11143 3399 11142
      3393 11151 3387 11158 3378 11167 3371 11187
      3367 11190 3369 11198 3373 11198 3400 11165
      3400 11150

$$

AD

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 12, 7:37 PM MST	Special Weather Statement	PSR	Gila	38 min
Jul 12, 8:17 PM MST	Severe Thunderstorm Warning	PSR	Gila, Pinal	43 min
Jul 12, 8:29 PM MST	Flash Flood Warning Considerable damage threat	PSR	Gila	3 hr
Jul 12, 9:18 PM MST	Special Weather Statement	PSR		42 min
Jul 12, 9:40 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	35 min
Jul 12, 10:05 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	25 min
Jul 12, 10:28 PM MST	Special Weather Statement	PSR	Maricopa	32 min
Jul 12, 11:35 PM MST	Special Weather Statement	PSR		40 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.