Alert archive / Nevada / Flash Flood Warnings in 2021

Flash Flood Warning 52, NWS Las Vegas, NV

July 22, 2021Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 22, 2021, 2:20 PM PDT for Clark County, Nevada. 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 22, 2021, 2:20 PM PDT (21:20 UTC)
Expired: Jul 22, 2021, 5:01 PM PDT
In force: 3 hr
Issued by: NWS Las Vegas, NV
Area: Storm-based polygon
Damage threat: Considerable
Flood severity: None

County Clark County, NV

The radar

The Las Vegas radar (KESX), 107 km from the middle of the area, began a volume at 21:20 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, 9.3 hours before the alert went out and 13 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: 112 J/kg
Mixed-layer CIN: -243 J/kg
Mixed-layer LCL: 2637 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 8 m²/s²
0-3 km storm-relative helicity: -4 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

002 
WGUS55 KVEF 222120
FFWVEF
NVC003-230030-
/O.NEW.KVEF.FF.W.0052.210722T2120Z-210723T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
220 PM PDT Thu Jul 22 2021

The National Weather Service in Las Vegas has issued a

* Flash Flood Warning for...
  Northwestern Clark County in southern Nevada...

* Until 530 PM PDT.

* At 220 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain in Highway 95 near Indian Springs. Between 1 and 1.5 
  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 low-water
           crossings, creeks, normally dry washes and roads.

* Some locations that will experience flash flooding include...
  Indian Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3649 11571 3661 11562 3651 11540 3644 11547
      3637 11563

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

$$

SC

2 follow-up statements

999 
WGUS75 KVEF 222254
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
354 PM PDT Thu Jul 22 2021

NVC003-230030-
/O.CON.KVEF.FF.W.0052.000000T0000Z-210723T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
354 PM PDT Thu Jul 22 2021

...FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM PDT THIS 
AFTERNOON FOR NORTHWESTERN CLARK COUNTY...

At 354 PM PDT, Doppler radar indicated the thunderstorms producing 
heavy rain along Highway 95 near Indian Springs has diminished. 
Runoff of the early heavy rain may still be producing flash flooding.

HAZARD...Life-threatening 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...
  Highway 95 south of Indian Springs.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3649 11571 3661 11562 3651 11540 3644 11547
      3637 11563

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

$$

SC

809 
WGUS75 KVEF 230001
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
501 PM PDT Thu Jul 22 2021

NVC003-230011-
/O.CAN.KVEF.FF.W.0052.000000T0000Z-210723T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
501 PM PDT Thu Jul 22 2021

...FLASH FLOOD WARNING IS CANCELLED FOR NORTHWESTERN CLARK COUNTY...

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

A Flash Flood Watch remains in effect until 900 PM PDT Clark County 
so stay weather aware for additional updates.

LAT...LON 3649 11571 3661 11562 3651 11540 3644 11547
      3637 11563

$$

TB

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 22, 10:18 AM PDT	Flash Flood Watch	VEF	Clark, Lincoln, Nye	11 hr
Jul 22, 12:53 PM PDT	Severe Thunderstorm Warning	VEF	Clark	26 min
Jul 22, 1:31 PM PDT	Severe Thunderstorm Warning	VEF	Clark	44 min
Jul 22, 1:35 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Lincoln	3 hr
Jul 22, 1:36 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Clark	3 hr
Jul 22, 1:49 PM PDT	Severe Thunderstorm Warning	VEF	Clark	41 min
Jul 22, 2:32 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Clark	3 hr
Jul 22, 3:03 PM PDT	Severe Thunderstorm Warning	VEF	Clark, Lincoln	42 min
Jul 22, 3:21 PM PDT	Flash Flood Warning Considerable damage threat	VEF	Clark, Lincoln	3 hr
Jul 22, 4:09 PM PDT	Severe Thunderstorm Warning	VEF	Clark	51 min

Nearby

Flash Flood Warnings in Nevada, 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.