Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 107, NWS Phoenix, AZ

July 29, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 29, 2021, 3:00 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 29, 2021, 3:00 PM MST (22:00 UTC)
Expired
Jul 29, 2021, 7:00 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), 134 km from the middle of the area, began a volume at 22:03 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 12:00Z, 10.0 hours before the alert went out and 124 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-pSkew-T log-p diagram, Phoenix, AZ at 12:00Z on 2021-07-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 371 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phoenix, AZ at 12:00Z on 2021-07-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 11 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
371 J/kg
Mixed-layer CIN
-231 J/kg
Mixed-layer LCL
2650 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
11 m²/s²
0-3 km storm-relative helicity
5 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

633 
WGUS55 KPSR 292200
FFWPSR
AZC013-300200-
/O.NEW.KPSR.FF.W.0107.210729T2200Z-210730T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
300 PM MST Thu Jul 29 2021

The National Weather Service in Phoenix has issued a

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

* Until 700 PM MST.

* At 300 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain in Midway basin. Between 1 and 1.5 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 with flow possible over parts of Highway 85.

  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...
  mainly rural areas of Maricopa County

This includes the following highways...
	AZ Route 85 between mile markers 19 and 28.

This includes the following streams and drainages...
  Tenmile Wash and Midway Wash.

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 3251 11285 3255 11289 3267 11295 3271 11291
      3271 11286 3261 11269 3251 11270 3251 11282

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

$$

SDB
1 follow-up statement
797 
WGUS75 KPSR 300011
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
511 PM MST Thu Jul 29 2021

AZC013-300200-
/O.CON.KPSR.FF.W.0107.000000T0000Z-210730T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
511 PM MST Thu Jul 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 7 PM MST THIS EVENING 
FOR MARICOPA COUNTY...

At 511 PM MST, Doppler radar indicated heavy rain fell in Midway 
basin. 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.

IMPACT...Life threatening flash flooding of creeks and streams,
         urban areas, highways, streets and underpasses.

Some locations that will experience flash flooding include...
  mainly rural areas of Maricopa County

This includes the following highways...
	AZ Route 85 between mile markers 19 and 28.

This includes the following streams and drainages...
  Tenmile Wash and Midway Wash.

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 3251 11285 3255 11289 3267 11295 3271 11291
      3271 11286 3261 11269 3251 11270 3251 11282

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

$$

SDB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 12:56 PM MSTSpecial Weather StatementPSRMaricopa49 min
Jul 29, 1:14 PM MSTSpecial Weather StatementPSR46 min
Jul 29, 1:22 PM MSTSpecial Weather StatementPSRYuma38 min
Jul 29, 1:24 PM MSTSpecial Weather StatementPSRGila51 min
Jul 29, 1:26 PM MSTFlash Flood WatchPSRLa Paz, Maricopa, Yuma40 hr
Jul 29, 1:33 PM MSTSpecial Weather StatementPSRGila42 min
Jul 29, 1:35 PM MSTAreal Flood AdvisoryPSRMaricopa22 min
Jul 29, 1:36 PM MSTFlash Flood Warning Considerable damage threatPSRGila6 hr
Jul 29, 1:42 PM MSTSevere Thunderstorm WarningPSRMaricopa48 min
Jul 29, 1:57 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Jul 29, 1:58 PM MSTSevere Thunderstorm WarningPSRGila, Pinal47 min
Jul 29, 2:07 PM MSTSpecial Weather StatementPSR53 min
Jul 29, 2:11 PM MSTSpecial Weather StatementPSRYuma49 min
Jul 29, 2:25 PM MSTAreal Flood AdvisoryPSRLa Paz, Maricopa3 hr
Jul 29, 2:32 PM MSTSpecial Weather StatementPSRYuma43 min
Jul 29, 2:35 PM MSTAreal Flood AdvisoryPSRMaricopa3 hr
Jul 29, 2:44 PM MSTSpecial Weather StatementPSRGila46 min
Jul 29, 3:04 PM MSTSpecial Weather StatementPSRLa Paz41 min
Jul 29, 3:17 PM MSTFlash Flood Warning EmergencyCatastrophic damage threatPSRGila3 hr
Jul 29, 3:19 PM MSTSpecial Weather StatementPSRYuma41 min
Jul 29, 3:23 PM MSTSpecial Weather StatementPSRGila52 min
Jul 29, 3:53 PM MSTAreal Flood AdvisoryPSRLa Paz, Maricopa, Yuma3 hr
Jul 29, 3:56 PM MSTFlash Flood Warning Considerable damage threatPSRGila4 hr
Jul 29, 3:59 PM MSTSpecial Weather StatementPSR61 min
Jul 29, 4:00 PM MSTAreal Flood AdvisoryPSRLa Paz3 hr
Jul 29, 4:17 PM MSTSpecial Weather StatementPSRLa Paz58 min
Jul 29, 4:18 PM MSTAreal Flood AdvisoryPSRLa Paz3 hr
Jul 29, 4:40 PM MSTAreal Flood AdvisoryPSRLa Paz3 hr
Jul 29, 4:42 PM MSTAreal Flood AdvisoryPSRYuma3 hr
Jul 29, 4:48 PM MSTSpecial Weather StatementPSR57 min

Nearby

Flash Flood Warnings in Arizona, 2021Every 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.