Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 23, NWS Las Vegas, NV

July 18, 2021Mohave County, Arizona; Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 18, 2021, 3:46 PM MST for Mohave County, Arizona; Clark County, Nevada. It was in force for 2 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 18, 2021, 3:46 PM MST (22:46 UTC)
Expired
Jul 18, 2021, 6:00 PM MST
In force
2 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Damage threat
Considerable
Flood severity
None

Counties Mohave County, AZ, Clark County, NV

The radar

The Las Vegas radar (KESX), 128 km from the middle of the area, began a volume at 22:50 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, 10.8 hours before the alert went out and 131 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 2021-07-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 424 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 2021-07-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 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
424 J/kg
Mixed-layer CIN
-164 J/kg
Mixed-layer LCL
2704 m above ground
0-6 km bulk shear
16 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
48 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

037 
WGUS55 KVEF 182246
FFWVEF
AZC015-NVC003-190100-
/O.NEW.KVEF.FF.W.0023.210718T2246Z-210719T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
346 PM PDT Sun Jul 18 2021

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  North Central Mohave County in northwestern Arizona...
  Northeastern Clark County in southern Nevada...

* Until 600 PM MST /600 PM PDT/.

* At 346 PM MST /346 PM PDT/, Doppler radar indicated thunderstorms 
  producing heavy rain across the warned area. Flash flooding is 
  ongoing or expected to begin shortly in Mesquite, Bunkerville, and 
  along Nevada State Route 170.

  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...
  Mesquite and Bunkerville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3635 11420 3675 11439 3676 11417 3681 11409
      3681 11406 3684 11399 3681 11398 3679 11404
      3636 11402

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

$$

JV
2 follow-up statements
002 
WGUS75 KVEF 190010
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
510 PM PDT Sun Jul 18 2021

AZC015-NVC003-190100-
/O.CON.KVEF.FF.W.0023.000000T0000Z-210719T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-Clark NV-
510 PM MST Sun Jul 18 2021 /510 PM PDT Sun Jul 18 2021/

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 6 PM MST/6 PM PDT/ 
THIS EVENING FOR NORTH CENTRAL MOHAVE AND NORTHEASTERN CLARK 
COUNTIES...

At 510 PM MST /510 PM PDT/, Doppler radar indicated thunderstorms 
producing heavy rain across the warned area. Flash flooding is 
ongoing or expected to begin shortly in Mesquite, Bunkerville, and 
along Nevada State Route 170. Though heavy rain has ended, moderate 
rain is expected to continue in the area, adding to the flash flood 
threat.

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...
  Mesquite and Bunkerville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3635 11420 3675 11439 3676 11417 3681 11409
      3681 11406 3684 11399 3681 11398 3679 11404
      3636 11402

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

$$

JV
473 
WGUS75 KVEF 190052
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
552 PM PDT Sun Jul 18 2021

AZC015-NVC003-190102-
/O.EXP.KVEF.FF.W.0023.000000T0000Z-210719T0100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-Clark NV-
552 PM MST Sun Jul 18 2021 /552 PM PDT Sun Jul 18 2021/

...FLASH FLOOD WARNING WILL EXPIRE AT 6 PM MST/6 PM PDT/ THIS 
EVENING FOR NORTH CENTRAL MOHAVE AND NORTHEASTERN CLARK COUNTIES...

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

LAT...LON 3635 11420 3675 11439 3676 11417 3681 11409
      3681 11406 3684 11399 3681 11398 3679 11404
      3636 11402

$$

JV

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 17, 5:33 PM MSTSevere Thunderstorm WarningVEFMohave57 min
Jul 18, 1:33 PM MSTAreal Flood AdvisoryVEFMohave80 min
Jul 18, 2:51 PM MSTFlash Flood Warning Considerable damage threatVEFMohave3 hr
Jul 18, 3:07 PM MSTSevere Thunderstorm WarningVEFMohave23 min
Jul 18, 3:14 PM MSTFlash Flood Warning Considerable damage threatVEFMohave3 hr
Jul 18, 1:05 PM MSTFlash Flood Warning Considerable damage threatVEFClark3 hr
Jul 18, 1:27 PM MSTAreal Flood AdvisoryVEFClark3 hr
Jul 18, 4:01 PM MSTFlash Flood Warning Considerable damage threatVEFClark119 min
Jul 18, 4:33 PM MSTFlash Flood Warning Considerable damage threatVEFClark3 hr

Nearby

Flash Flood Warnings in Arizona, 2021Flash Flood Warnings in Nevada, 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.