Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 53, NWS Phoenix, AZ

July 21, 2021Yuma County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 21, 2021, 8:01 PM MST for Yuma County, Arizona. It was in force for 4 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 21, 2021, 8:01 PM MST (03:01 UTC)
Expired: Jul 22, 2021, 12:00 AM MST
In force: 4 hr
Issued by: NWS Phoenix, AZ
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Yuma County, AZ

The radar

The Yuma radar (KYUX), 101 km from the middle of the area, began a volume at 03:02 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, 3.0 hours before the alert went out and 180 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: 760 J/kg
Mixed-layer CIN: -12 J/kg
Mixed-layer LCL: 3156 m above ground
0-6 km bulk shear: 19 kt
0-1 km storm-relative helicity: -21 m²/s²
0-3 km storm-relative helicity: 10 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.7

Open this sounding in Storm Lab

The text

As transmitted.

761 
WGUS55 KPSR 220301
FFWPSR
AZC027-220700-
/O.NEW.KPSR.FF.W.0053.210722T0301Z-210722T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
801 PM MST Wed Jul 21 2021

The National Weather Service in Phoenix has issued a

* Flash Flood Warning for...
  Northeastern Yuma County in southwestern Arizona...

* Until midnight MST.

* At 801 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. Between 1 and 3 inches of rain 
  have fallen within King Valley in the Kofa National Wildlife 
  Refuge. 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...
  Palm Canyon.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

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

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 3305 11365 3300 11362 3295 11362 3285 11364
      3284 11368 3285 11375 3309 11405 3317 11414
      3323 11418 3326 11416 3333 11412 3337 11404
      3333 11393 3330 11389 3326 11386

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

$$

Iniguez

1 follow-up statement

158 
WGUS75 KPSR 220657
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1157 PM MST Wed Jul 21 2021

AZC027-220707-
/O.EXP.KPSR.FF.W.0053.000000T0000Z-210722T0700Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yuma AZ-
1157 PM MST Wed Jul 21 2021

...FLASH FLOOD WARNING WILL EXPIRE AT MIDNIGHT MST TONIGHT FOR 
NORTHEASTERN YUMA COUNTY...

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 3305 11365 3300 11362 3295 11362 3285 11364
      3284 11368 3285 11375 3309 11405 3317 11414
      3323 11418 3326 11416 3333 11412 3337 11404
      3333 11393 3330 11389 3326 11386

$$

18

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 5:37 PM MST	Special Weather Statement	PSR	Yuma	38 min
Jul 21, 5:41 PM MST	Special Weather Statement	PSR		49 min
Jul 21, 6:18 PM MST	Severe Thunderstorm Warning	PSR	La Paz, Yuma	42 min
Jul 21, 6:20 PM MST	Special Weather Statement	PSR	Gila	40 min
Jul 21, 6:47 PM MST	Special Weather Statement	PSR		43 min
Jul 21, 6:59 PM MST	Special Weather Statement	PSR	Yuma	46 min
Jul 21, 7:06 PM MST	Areal Flood Advisory	PSR	Gila	3 hr
Jul 21, 7:10 PM MST	Special Weather Statement	PSR	La Paz	50 min
Jul 21, 7:17 PM MST	Areal Flood Advisory	PSR	Yuma	44 min
Jul 21, 7:40 PM MST	Dust Storm Warning	PSR	Yuma	35 min
Jul 21, 8:13 PM MST	Dust Storm Advisory	PSR	Yuma	47 min
Jul 21, 9:06 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	39 min
Jul 21, 10:06 PM MST	Dust Storm Advisory	PSR	Maricopa, Pinal	39 min
Jul 21, 10:11 PM MST	Special Weather Statement	PSR	Pinal	49 min
Jul 21, 10:23 PM MST	Special Weather Statement	PSR	Maricopa	37 min
Jul 21, 10:25 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	16 min
Jul 21, 10:39 PM MST	Special Weather Statement	PSR		36 min
Jul 21, 10:51 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	24 min
Jul 21, 11:12 PM MST	Special Weather Statement	PSR		48 min
Jul 21, 11:15 PM MST	Special Weather Statement	PSR	Pinal	45 min
Jul 22, 12:28 AM MST	Flash Flood Warning Considerable damage threat	PSR	Maricopa	4 hr
Jul 22, 12:32 AM MST	Areal Flood Advisory	PSR	Maricopa	118 min
Jul 22, 3:06 PM MST	Special Weather Statement	PSR		54 min
Jul 22, 3:43 PM MST	Special Weather Statement	PSR	Maricopa	47 min
Jul 22, 3:58 PM MST	Severe Thunderstorm Warning	PSR	Maricopa	33 min
Jul 22, 4:30 PM MST	Dust Storm Advisory	PSR	Yuma	41 min
Jul 22, 4:53 PM MST	Areal Flood Advisory	PSR	Maricopa	3 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.