Alert archive / Nevada / Flash Flood Warnings in 2018

Flash Flood Warning 101, NWS Las Vegas, NV

August 9, 2018Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Aug 9, 2018, 3:11 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
Aug 9, 2018, 3:11 PM PDT (22:11 UTC)
Expired
Aug 9, 2018, 6:15 PM PDT
In force
3 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County Clark County, NV

The radar

The Las Vegas radar (KESX), 97 km from the middle of the area, began a volume at 22:14 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, 10.2 hours before the alert went out and 31 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 2018-08-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 551 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 2018-08-09The 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
551 J/kg
Mixed-layer CIN
-340 J/kg
Mixed-layer LCL
2902 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
131 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.4

Open this sounding in Storm Lab

The text

As transmitted.

700 
WGUS55 KVEF 092211
FFWVEF
NVC003-100115-
/O.NEW.KVEF.FF.W.0101.180809T2211Z-180810T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
311 PM PDT THU AUG 9 2018

The National Weather Service in Las Vegas has issued a

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

* Until 615 PM PDT.

* At 310 PM PDT, Doppler radar indicated thunderstorms producing
  heavy rain across the warned area. Up to one inch of rain has
  already fallen. Flash flooding is expected to begin shortly.

* Some locations that will experience flooding include...
  Rainbow Canyon, Spring Mountains and Mary Jane Falls Campground. 
  This includes western portions of the Carpenter One burn scar.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3615 11590 3619 11590 3630 11575 3626 11561
      3614 11567 3607 11578

$$

WOLF
2 follow-up statements
012 
WGUS75 KVEF 092332
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
432 PM PDT THU AUG 9 2018

NVC003-100115-
/O.CON.KVEF.FF.W.0101.000000T0000Z-180810T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
432 PM PDT THU AUG 9 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 615 PM PDT FOR
WESTERN CLARK COUNTY...

At 431 PM PDT, Doppler radar indicated thunderstorms producing heavy
rain across the warned area.  Flash flooding is expected to begin
shortly.

Excessive rainfall over the burn scar may result in debris flow 
moving through the Carpenter One burn scar. The debris flow can 
consist of rock, mud, vegetation and other loose materials.

Some locations that will experience flooding include...
Rainbow Canyon, Spring Mountains and Mary Jane Falls Campground. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3615 11590 3619 11590 3630 11575 3626 11561
      3614 11567 3607 11578

$$

WOLF
773 
WGUS75 KVEF 100105
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
605 PM PDT THU AUG 9 2018

NVC003-100115-
/O.EXP.KVEF.FF.W.0101.000000T0000Z-180810T0115Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
605 PM PDT THU AUG 9 2018

...THE FLASH FLOOD WARNING FOR WESTERN CLARK COUNTY WILL EXPIRE AT
615 PM PDT...

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

LAT...LON 3615 11590 3619 11590 3630 11575 3626 11561
      3614 11567 3607 11578

$$

Wolf

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 8, 5:20 PM PDTAreal Flood AdvisoryVEFClark3 hr
Aug 8, 5:29 PM PDTSevere Thunderstorm WarningVEFClark46 min

Nearby

Flash Flood Warnings in Nevada, 2018Every flash flood warning in 2018

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.