Alert archive / Arizona / Flash Flood Warnings in 2021

Flash Flood Warning 35, NWS Las Vegas, NV

July 20, 2021Mohave County, Arizona

NWS Las Vegas, NV issued this flash flood warning at Jul 20, 2021, 3:28 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, 3:28 PM MST (22:28 UTC)
Expired: Jul 20, 2021, 6:30 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), 137 km from the middle of the area, began a volume at 22:30 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

Flgstf/Belemont, AZ (KFGZ), launched 12:00Z, 10.5 hours before the alert went out and 150 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: 396 J/kg
Mixed-layer CIN: -58 J/kg
Mixed-layer LCL: 1392 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 16 m²/s²
0-3 km storm-relative helicity: 5 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

947 
WGUS55 KVEF 202228
FFWVEF
AZC015-210130-
/O.NEW.KVEF.FF.W.0035.210720T2228Z-210721T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

The National Weather Service in Las Vegas has issued a

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

* Until 630 PM MST.

* At 328 PM MST, Doppler radar indicated thunderstorms producing 
  heavy rain across the warned area. 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...
  Peach Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3555 11333 3553 11351 3576 11350 3574 11340
      3579 11333 3574 11333 3563 11333 3562 11333
      3559 11333

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

$$

JS

2 follow-up statements

687 
WGUS75 KVEF 210018
FFSVEF

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

AZC015-210130-
/O.CON.KVEF.FF.W.0035.000000T0000Z-210721T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
518 PM MST Tue Jul 20 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM MST THIS 
EVENING FOR CENTRAL MOHAVE COUNTY...

At 518 PM MST, Doppler radar indicated heavy rain due to 
thunderstorms has ended over the warned area however the warning 
will continue with clusters of thunderstorms to the west and 
southwest generally moving to the northeast. Additional flash 
flooding is possible.

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 could experience flash flooding include...
  Diamond Creek road, Diamond Creek Campground and Peach Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

In hilly terrain there are hundreds of low water crossings which are 
potentially dangerous in heavy rain. Do not attempt to cross flooded 
roads. Find an alternate route.

&&

LAT...LON 3555 11333 3553 11351 3576 11350 3574 11340
      3579 11333 3574 11333 3563 11333 3562 11333
      3559 11333

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

$$

JS

253 
WGUS75 KVEF 210128
FFSVEF

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

AZC015-210138-
/O.EXP.KVEF.FF.W.0035.000000T0000Z-210721T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Mohave AZ-
628 PM MST Tue Jul 20 2021

...FLASH FLOOD WARNING WILL EXPIRE AT 630 PM MST THIS EVENING FOR 
CENTRAL 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 3555 11333 3553 11351 3576 11350 3574 11340
      3579 11333 3574 11333 3563 11333 3562 11333
      3559 11333

$$

JS

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 5:07 PM MST	Flash Flood Warning Considerable damage threat	VEF	Mohave	3 hr
Jul 20, 3:13 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.