Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 117, NWS Las Vegas, NV

August 29, 2021Mohave County, Arizona

NWS Las Vegas, NV issued this flash flood warning at Aug 29, 2021, 4:18 PM MST for Mohave County, Arizona. It was in force for 117 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Aug 29, 2021, 4:18 PM MST (23:18 UTC)
Expired
Aug 29, 2021, 6:15 PM MST
In force
117 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

County Mohave County, AZ

The radar

The Las Vegas radar (KESX), 91 km from the middle of the area, began a volume at 23:17 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

Las Vegas, NV (KVEF), launched 12:00Z, 11.3 hours before the alert went out and 185 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, Las Vegas, NV at 12:00Z on 2021-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 350 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, Las Vegas, NV at 12:00Z on 2021-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -24 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
350 J/kg
Mixed-layer CIN
-157 J/kg
Mixed-layer LCL
3268 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-24 m²/s²
0-3 km storm-relative helicity
-10 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

220 
WGUS55 KVEF 292318
FFWVEF
AZC015-300115-
/O.NEW.KVEF.FF.W.0117.210829T2318Z-210830T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
418 PM PDT Sun Aug 29 2021

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  Southwestern Mohave County in northwestern Arizona...

* Until 615 PM MST.

* At 418 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across Golden Valley, south of highway 68. 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 low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Golden Valley.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3517 11406 3513 11410 3508 11412 3503 11415
      3498 11418 3496 11420 3498 11423 3502 11426
      3506 11427 3510 11428 3515 11428 3519 11429
      3521 11429 3523 11429 3523 11420 3523 11413
      3521 11410 3517 11407

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

$$

BKP
2 follow-up statements
243 
WGUS75 KVEF 300013
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
513 PM PDT Sun Aug 29 2021

AZC015-300115-
/O.CON.KVEF.FF.W.0117.000000T0000Z-210830T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
513 PM MST Sun Aug 29 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM MST THIS 
EVENING FOR SOUTHWESTERN MOHAVE COUNTY...

At 513 PM MST, Doppler radar indicated thunderstorms producing heavy 
rain continue near and along Interstate 40 between Kingman and 
Yucca. 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 low-water crossings,
         creeks, normally dry washes and roads.

Some locations that will experience flash flooding include...
  Golden Valley and the Sacramento Wash.

  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3517 11406 3513 11410 3508 11412 3503 11415
      3498 11418 3496 11420 3498 11423 3502 11426
      3506 11427 3510 11428 3515 11428 3519 11429
      3521 11429 3523 11429 3523 11420 3523 11413
      3521 11410 3517 11407

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

$$

BKP
232 
WGUS75 KVEF 300110
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
610 PM PDT Sun Aug 29 2021

AZC015-300120-
/O.EXP.KVEF.FF.W.0117.000000T0000Z-210830T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
610 PM MST Sun Aug 29 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 615 PM MST THIS EVENING FOR 
SOUTHWESTERN MOHAVE COUNTY...

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

LAT...LON 3517 11406 3513 11410 3508 11412 3503 11415
      3498 11418 3496 11420 3498 11423 3502 11426
      3506 11427 3510 11428 3515 11428 3519 11429
      3521 11429 3523 11429 3523 11420 3523 11413
      3521 11410 3517 11407

$$

BKP

The office that day

Everything else NWS Las Vegas, NV issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 29, 3:15 PM MSTSevere Thunderstorm WarningVEFMohave32 min
Aug 29, 3:43 PM MSTFlash Flood Warning Considerable damage threatVEFMohave3 hr

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.