Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 15, NWS Phoenix, AZ

July 3, 2021Maricopa County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Jul 3, 2021, 6:10 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 3, 2021, 6:10 PM MST (01:10 UTC)
Expired
Jul 3, 2021, 10:15 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), 87 km from the middle of the area, began a volume at 01:11 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, 1.2 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-pSkew-T log-p diagram, Phoenix, AZ at 00:00Z on 2021-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 281 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Phoenix, AZ at 00:00Z on 2021-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -30 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
281 J/kg
Mixed-layer CIN
-14 J/kg
Mixed-layer LCL
3054 m above ground
0-6 km bulk shear
4 kt
0-1 km storm-relative helicity
-30 m²/s²
0-3 km storm-relative helicity
3 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

674 
WGUS55 KPSR 040110
FFWPSR
AZC013-040515-
/O.NEW.KPSR.FF.W.0015.210704T0110Z-210704T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
610 PM MST Sat Jul 3 2021

The National Weather Service in Phoenix has issued a

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

* Until 1015 PM MST.

* At 610 PM MST, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the warned area. Between 
  0.5 and 2 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...
  Phoenix, Glendale, Peoria, Surprise, Sun City West, Wittmann, Sun 
  City, Circle City, Beardsley, Surprise Stadium and Vistancia.

This includes the following highways...
	US Highway 60 between mile markers 123 and 132.
	AZ Route 303 between mile markers 117 and 126.
	AZ Route 74 between mile markers 10 and 19.
	AZ Interstate 17 near mile marker 237.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3399 11219 3399 11213 3371 11219 3366 11225
      3362 11239 3375 11256 3387 11262 3394 11250
      3388 11228 3389 11228 3391 11226 3391 11224
      3392 11224 3394 11223 3394 11224 3396 11224
      3396 11223 3397 11220

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

$$

SDB
2 follow-up statements
240 
WGUS75 KPSR 040328
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
828 PM MST Sat Jul 3 2021

AZC013-040515-
/O.CON.KPSR.FF.W.0015.000000T0000Z-210704T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
828 PM MST Sat Jul 3 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1015 PM MST THIS 
EVENING FOR MARICOPA COUNTY...

At 828 PM MST, Doppler radar and automated rain gauges indicated 
heavy rain fell across the warned area earlier. Light to moderate 
rain is still falling in the 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...
  Surprise, Sun City West, Beardsley and Vistancia.

This includes the following highways...
	US Highway 60 between mile markers 138 and 141.
	AZ Route 303 between mile markers 120 and 129.
	AZ Route 74 between mile markers 10 and 19.

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.

Please report observed flooding to local emergency services or law 
enforcement and request they pass this information to the National 
Weather Service when you can do so safely.

&&

LAT...LON 3378 11226 3369 11229 3365 11237 3380 11254
      3387 11252 3390 11238 3388 11228 3389 11228
      3391 11224 3392 11224 3394 11223 3394 11224
      3395 11224 3396 11224 3396 11223 3392 11220
      3383 11225

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

$$

SDB
110 
WGUS75 KPSR 040512
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1012 PM MST Sat Jul 3 2021

AZC013-040522-
/O.EXP.KPSR.FF.W.0015.000000T0000Z-210704T0515Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Maricopa AZ-
1012 PM MST Sat Jul 3 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1015 PM MST THIS EVENING 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 3378 11226 3369 11229 3365 11237 3380 11254
      3387 11252 3390 11238 3388 11228 3389 11228
      3391 11224 3392 11224 3394 11223 3394 11224
      3395 11224 3396 11224 3396 11223 3392 11220
      3383 11225

$$

SDB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 3, 5:11 PM MSTSpecial Weather StatementPSR49 min
Jul 3, 5:20 PM MSTSpecial Weather StatementPSR25 min
Jul 3, 5:29 PM MSTAreal Flood AdvisoryPSRPinal3 hr
Jul 3, 5:32 PM MSTSpecial Weather StatementPSRMaricopa43 min
Jul 3, 5:38 PM MSTFlash Flood Warning Considerable damage threatPSRGila4 hr
Jul 3, 5:41 PM MSTDust Storm WarningPSRMaricopa, Pinal44 min
Jul 3, 5:43 PM MSTDust Storm WarningPSRMaricopa62 min
Jul 3, 5:56 PM MSTAreal Flood AdvisoryPSRMaricopa3 hr
Jul 3, 6:05 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Jul 3, 6:20 PM MSTSpecial Weather StatementPSRMaricopa40 min
Jul 3, 6:23 PM MSTFlash Flood Warning Considerable damage threatPSRGila, Maricopa4 hr
Jul 3, 6:31 PM MSTSpecial Weather StatementPSRGila44 min
Jul 3, 6:43 PM MSTDust Storm WarningPSRLa Paz, Maricopa, Pinal, Yuma62 min
Jul 3, 6:46 PM MSTFlash Flood Warning Considerable damage threatPSRGila, Maricopa4 hr
Jul 3, 7:13 PM MSTFlash Flood Warning Considerable damage threatPSRMaricopa4 hr
Jul 4, 3:09 PM MSTFlash Flood Warning Considerable damage threatPSRGila4 hr
Jul 4, 3:43 PM MSTSpecial Weather StatementPSRGila32 min
Jul 4, 4:10 PM MSTFlash Flood Warning Considerable damage threatPSRGila4 hr
Jul 4, 4:36 PM MSTSpecial Weather StatementPSRGila24 min
Jul 4, 4:51 PM MSTSpecial Weather StatementPSRGila39 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.