Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 41, NWS Phoenix, AZ

July 15, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 15, 2021, 5:06 PM MST for Maricopa 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 15, 2021, 5:06 PM MST (00:06 UTC)
Expired: Jul 15, 2021, 9:15 PM MST
In force: 4 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), 27 km from the middle of the area, began a volume at 00:08 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, 0.1 hours before the alert went out and 20 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: 1128 J/kg
Mixed-layer CIN: -8 J/kg
Mixed-layer LCL: 2310 m above ground
0-6 km bulk shear: 4 kt
0-1 km storm-relative helicity: -12 m²/s²
0-3 km storm-relative helicity: 28 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

738 
WGUS55 KPSR 160006
FFWPSR
AZC013-160415-
/O.NEW.KPSR.FF.W.0041.210716T0006Z-210716T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
506 PM MST Thu Jul 15 2021

The National Weather Service in Phoenix has issued a

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

* Until 915 PM MST.

* At 506 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.75 and 1.25 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. 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...
  Mesa, Scottsdale, Tempe, Fountain Hills, Falcon Field Airport, 
  Salt River Indian Community, Granite Reef Dam and Mesa Riverview 
  Mall.

This includes the following highways...
	AZ Route 202 between mile markers 10 and 19.
	AZ Route 101 between mile markers 49 and 52.
	AZ Route 87 between mile markers 174 and 183.

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.

&&

LAT...LON 3358 11181 3359 11174 3357 11167 3353 11166
      3348 11168 3344 11175 3342 11187 3344 11191
      3350 11188

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

$$

SDB

1 follow-up statement

092 
WGUS75 KPSR 160416
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
916 PM MST Thu Jul 15 2021

AZC013-160426-
/O.EXP.KPSR.FF.W.0041.000000T0000Z-210716T0415Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
916 PM MST Thu Jul 15 2021

...FLASH FLOOD WARNING HAS EXPIRED FOR MARICOPA COUNTY...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed remaining road closures.

LAT...LON 3358 11181 3359 11174 3357 11167 3353 11166
      3348 11168 3344 11175 3342 11187 3344 11191
      3350 11188

$$

SDB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 15, 5:07 PM MST	Special Weather Statement	PSR		38 min
Jul 15, 5:12 PM MST	Severe Thunderstorm Warning	PSR	Maricopa, Pinal	48 min
Jul 15, 5:33 PM MST	Special Weather Statement	PSR	La Paz	42 min
Jul 15, 5:43 PM MST	Special Weather Statement	PSR		47 min
Jul 15, 6:00 PM MST	Areal Flood Advisory	PSR	Maricopa, Pinal	3 hr
Jul 15, 6:08 PM MST	Special Weather Statement	PSR	Pinal	52 min
Jul 16, 8:54 AM MST	Special Weather Statement	PSR	Pinal	36 min
Jul 16, 9:48 AM MST	Special Weather Statement	PSR		27 min
Jul 16, 11:21 AM MST	Areal Flood Advisory	PSR	Maricopa	111 min
Jul 16, 2:56 PM MST	Special Weather Statement	PSR	Gila	34 min
Jul 16, 3:27 PM MST	Special Weather Statement	PSR		33 min
Jul 16, 3:37 PM MST	Special Weather Statement	PSR	Gila	38 min
Jul 16, 4:39 PM MST	Special Weather Statement	PSR	Gila	36 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.