Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 38, NWS Las Vegas, NV

July 20, 2021Mohave County, Arizona

NWS Las Vegas, NV issued this flash flood warning at Jul 20, 2021, 6:47 PM MST for Mohave County, Arizona. It was in force for 3 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 20, 2021, 6:47 PM MST (01:47 UTC)
Expired: Jul 20, 2021, 9:45 PM MST
In force: 3 hr
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), 41 km from the middle of the area, began a volume at 01:49 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 00:00Z, 1.8 hours before the alert went out and 105 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: 183 J/kg
Mixed-layer CIN: -5 J/kg
Mixed-layer LCL: 3414 m above ground
0-6 km bulk shear: 15 kt
0-1 km storm-relative helicity: 52 m²/s²
0-3 km storm-relative helicity: 50 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

458 
WGUS55 KVEF 210147
FFWVEF
AZC015-210445-
/O.NEW.KVEF.FF.W.0038.210721T0147Z-210721T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
647 PM PDT Tue Jul 20 2021

The National Weather Service in Las Vegas has issued a

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

* Until 945 PM MST.

* At 647 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain along Temple Bar Road. 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...
  Temple Bar Road, Willow Beach area and other mainly rural areas of 
  Northwestern Mohave County

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 3581 11454 3587 11467 3587 11466 3604 11448
      3598 11436 3597 11438

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

$$

JS

2 follow-up statements

008 
WGUS75 KVEF 210316
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
816 PM PDT Tue Jul 20 2021

AZC015-210445-
/O.CON.KVEF.FF.W.0038.000000T0000Z-210721T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
816 PM MST Tue Jul 20 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 945 PM MST THIS 
EVENING FOR NORTHWESTERN MOHAVE COUNTY...

At 816 PM MST, Doppler radar indicates heavy rain has ended across 
the warned area. However, due to the possibility of continuing 
impacts due to the earlier heavy rain, the warning is continued. 
Additional flash flooding is no longer expected.

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...
  Temple Bar Road, Willow Beach access and mainly rural areas of 
  Northwestern Mohave County

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 3581 11454 3587 11467 3587 11466 3604 11448
      3598 11436 3597 11438

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

$$

JS

638 
WGUS75 KVEF 210441
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
941 PM PDT Tue Jul 20 2021

AZC015-210451-
/O.EXP.KVEF.FF.W.0038.000000T0000Z-210721T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
941 PM MST Tue Jul 20 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 945 PM MST THIS EVENING FOR 
NORTHWESTERN MOHAVE COUNTY...

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

LAT...LON 3581 11454 3587 11467 3587 11466 3604 11448
      3598 11436 3597 11438

$$

JS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 21, 12:07 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	4 hr
Jul 21, 1:24 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	5 hr
Jul 21, 2:25 PM MST	Areal Flood Advisory	VEF	Mohave	2 hr
Jul 21, 3:35 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr
Jul 21, 4:03 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	2 hr
Jul 21, 4:18 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	2 hr
Jul 21, 4:56 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr

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.