Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 163, NWS Phoenix, AZ

August 12, 2021Yuma County, Arizona

NWS Phoenix, AZ issued this flash flood warning at Aug 12, 2021, 7:16 PM MST for Yuma County, Arizona. It was in force for 4 hr. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 12, 2021, 7:16 PM MST (02:16 UTC)
Expired
Aug 12, 2021, 11:15 PM 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), 74 km from the middle of the area, began a volume at 02:19 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.

What was reported inside it

TimeReportWhereRemark
Aug 12, 7:30 PM MSTHEAVY RAIN 1.251 N Tacna, AZ

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Phoenix, AZ (KPSR), launched 00:00Z, 2.3 hours before the alert went out and 198 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 2021-08-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 760 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 00:00Z on 2021-08-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 13 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
760 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
1919 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
13 m²/s²
0-3 km storm-relative helicity
9 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

258 
WGUS55 KPSR 130216
FFWPSR
AZC027-130615-
/O.NEW.KPSR.FF.W.0163.210813T0216Z-210813T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Phoenix AZ
716 PM MST Thu Aug 12 2021

The National Weather Service in Phoenix has issued a

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

* Until 1115 PM MST.

* At 716 PM MST, Doppler radar 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.

  IMPACT...Life threatening flash flooding of normally dry
           washes, highways, streets and underpasses.

* Some locations that will experience flash flooding include...
  Tyson, Tacna and Roll.

This includes the following highways...
	AZ Interstate 8 between mile markers 38 and 47.

This includes the following streams and drainages...
  Big Eye Wash, Mohawk Wash,  Mohawk Canal

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3299 11390 3283 11376 3261 11377 3258 11388
      3272 11410 3282 11418 3296 11423

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

$$

AJ
3 follow-up statements
287 
WGUS75 KPSR 130257
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
757 PM MST Thu Aug 12 2021

AZC027-130615-
/O.CON.KPSR.FF.W.0163.000000T0000Z-210813T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yuma AZ-
757 PM MST Thu Aug 12 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM MST THIS 
EVENING FOR CENTRAL YUMA COUNTY...

At 757 PM MST, Doppler radar indicated thunderstorms have produced 
between 1 and 2 inches of rain. 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 normally dry washes,
         highways, streets and underpasses.

Some locations that will experience flash flooding include...
  Tyson, Tacna and Roll.

This includes the following highways...
	AZ Interstate 8 between mile markers 38 and 47.

This includes the following streams and drainages...
  Big Eye Wash, Mohawk Wash, Mohawk Canal, and small washes feeding 
  into the Gila River..

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Turn around, don't drown when encountering flooded roads. Most flood 
deaths occur in vehicles. It is especially difficult at night to 
determine the depth of water.

&&

LAT...LON 3299 11390 3283 11376 3261 11377 3258 11388
      3272 11410 3282 11418 3296 11423

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

$$

AJ
017 
WGUS75 KPSR 130511
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1011 PM MST Thu Aug 12 2021

AZC027-130615-
/O.CON.KPSR.FF.W.0163.000000T0000Z-210813T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yuma AZ-
1011 PM MST Thu Aug 12 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1115 PM MST THIS 
EVENING FOR CENTRAL YUMA COUNTY...

At 1011 PM MST, Doppler radar 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.

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

Some locations that will experience flash flooding include...
  Tyson, Tacna and Roll.

This includes the following highways...
	AZ Interstate 8 between mile markers 38 and 47.

This includes the following streams and drainages...
  Big Eye Wash, Mohawk Wash, Gila River and Mohawk Canal.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3299 11390 3283 11376 3261 11377 3258 11388
      3272 11410 3282 11418 3296 11423

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

$$

Rogers
364 
WGUS75 KPSR 130611
FFSPSR

Flash Flood Statement
National Weather Service Phoenix AZ
1111 PM MST Thu Aug 12 2021

AZC027-130621-
/O.EXP.KPSR.FF.W.0163.000000T0000Z-210813T0615Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Yuma AZ-
1111 PM MST Thu Aug 12 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 1115 PM MST THIS EVENING FOR 
CENTRAL 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 3299 11390 3283 11376 3261 11377 3258 11388
      3272 11410 3282 11418 3296 11423

$$

CK

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 5:16 PM MSTSpecial Weather StatementPSRYuma44 min
Aug 12, 5:17 PM MSTSpecial Weather StatementPSRYuma43 min
Aug 12, 5:53 PM MSTAreal Flood AdvisoryPSRYuma3 hr
Aug 12, 6:28 PM MSTSpecial Weather StatementPSRLa Paz47 min
Aug 12, 6:30 PM MSTSpecial Weather StatementPSRYuma45 min
Aug 12, 6:42 PM MSTAreal Flood AdvisoryPSRLa Paz3 hr
Aug 12, 6:47 PM MSTAreal Flood AdvisoryPSRMaricopa, Yuma3 hr
Aug 12, 6:50 PM MSTSevere Thunderstorm WarningPSRYuma40 min
Aug 12, 6:52 PM MSTSevere Thunderstorm WarningPSRLa Paz38 min
Aug 12, 7:25 PM MSTSevere Thunderstorm WarningPSRLa Paz50 min
Aug 12, 7:42 PM MSTAreal Flood AdvisoryPSRLa Paz, Yuma3 hr
Aug 12, 7:56 PM MSTSpecial Weather StatementPSRLa Paz49 min
Aug 12, 8:05 PM MSTDust Storm AdvisoryPSRLa Paz, Yuma55 min
Aug 12, 8:48 PM MSTFlash Flood Warning Considerable damage threatPSRLa Paz, Yuma4 hr
Aug 13, 2:50 PM MSTSpecial Weather StatementPSRGila40 min
Aug 13, 3:30 PM MSTSevere Thunderstorm WarningPSRGila45 min
Aug 13, 3:36 PM MSTFlash Flood Warning Considerable damage threatPSRGila4 hr
Aug 13, 4:12 PM MSTFlash Flood Warning Considerable damage threatPSRGila4 hr
Aug 13, 4:14 PM MSTSpecial Weather StatementPSRGila46 min
Aug 13, 4:34 PM MSTSevere Thunderstorm WarningPSRGila, Maricopa, Pinal41 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.