Alert archive / Nevada / Flash Flood Warnings in 2018

Flash Flood Warning 82, NWS Las Vegas, NV

July 20, 2018Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 20, 2018, 7:05 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 20, 2018, 7:05 PM PDT (02:05 UTC)
Expired: Jul 20, 2018, 10:00 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), 45 km from the middle of the area, began a volume at 02:04 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, 2.1 hours before the alert went out and 52 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: 1115 J/kg
Mixed-layer CIN: -47 J/kg
Mixed-layer LCL: 2787 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: -4 m²/s²
0-3 km storm-relative helicity: 9 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted.

529 
WGUS55 KVEF 210205
FFWVEF
NVC003-210500-
/O.NEW.KVEF.FF.W.0082.180721T0205Z-180721T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
705 PM PDT FRI JUL 20 2018

The National Weather Service in Las Vegas has issued a

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

* Until 1000 PM PDT.

* At 704 PM PDT, Doppler radar indicated thunderstorms producing 
  heavy rain near Green Valley. Flash flooding is expected to begin 
  shortly.  Rain rates of over One-Third of an inch per hour have 
  been recorded. 

* Some locations that will experience flooding include...
  Las Vegas, Henderson, North Las Vegas, Anthem, The Strip, Nellis
  AFB, Downtown Las Vegas, East Las Vegas, Sam Boyd Stadium, The
  Motor Speedway, Southern Highlands, Green Valley, Paradise, Lake
  Las Vegas, Enterprise, Sloan, Seven Hills, Silverado Ranch,
  Mccarran International Airport and Black Mtn.

This includes Interstate 15 in Nevada near mile marker 25.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3614 11520 3594 11521 3582 11514 3588 11498
      3627 11488 3627 11509

$$

Outler

3 follow-up statements

387 
WGUS75 KVEF 210229
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
729 PM PDT FRI JUL 20 2018

NVC003-210500-
/O.CON.KVEF.FF.W.0082.000000T0000Z-180721T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
729 PM PDT FRI JUL 20 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 PM PDT FOR
CENTRAL CLARK COUNTY...

At 727 PM PDT, Doppler radar and automated rain gauges indicated 
thunderstorms producing heavy rain near Green Valley. A rain  gauge 
in Green Valley has picked up three-quarters of an inch of rain in 
the past hour. Flash flooding is likely.

Some locations that will experience flooding include...
Henderson, Anthem, Nellis AFB, East Las Vegas, Sam Boyd Stadium, The 
Motor Speedway, Southern Highlands, Green Valley, Paradise, Lake Las 
Vegas, Seven Hills, Silverado Ranch, and Black Mtn.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3614 11520 3594 11521 3582 11514 3588 11498
      3627 11488 3627 11509

$$

Outler

089 
WGUS75 KVEF 210324
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
824 PM PDT FRI JUL 20 2018

NVC003-210500-
/O.CON.KVEF.FF.W.0082.000000T0000Z-180721T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
824 PM PDT FRI JUL 20 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1000 PM PDT FOR
CENTRAL CLARK COUNTY...

At 823 PM PDT, thunderstorm activity had mostly diminished across 
the Las Vegas Valley. However...runoff will persist through 10 pm 
and area washes east of the Las Vegas strip will remain high through 
the evening. 

Some locations that will experience flooding include...
Henderson, Anthem, East Las Vegas, Sam Boyd Stadium, Southern 
Highlands, Green Valley, Paradise, Lake Las Vegas, Seven Hills, 
Silverado Ranch, and Black Mtn.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3614 11520 3594 11521 3582 11514 3588 11498
      3627 11488 3627 11509

$$

Outler

623 
WGUS75 KVEF 210451
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
951 PM PDT FRI JUL 20 2018

NVC003-210500-
/O.EXP.KVEF.FF.W.0082.000000T0000Z-180721T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
951 PM PDT FRI JUL 20 2018

...THE FLASH FLOOD WARNING FOR CENTRAL CLARK COUNTY WILL EXPIRE AT
1000 PM PDT...

The heavy rain has ended. Flooding is no longer expected to pose a 
threat. Please continue to heed any remaining road closures and 
avoid washes and drainages will continue to observe elevated flows 
through the evening.

LAT...LON 3614 11520 3594 11521 3582 11514 3588 11498
      3627 11488 3627 11509

$$

Outler

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 20, 6:54 PM PDT	Severe Thunderstorm Warning	VEF	Clark	51 min
Jul 20, 8:54 PM PDT	Severe Thunderstorm Warning	VEF	Nye	51 min
Jul 21, 9:22 AM PDT	Severe Thunderstorm Warning	VEF	Clark	53 min
Jul 21, 9:41 AM PDT	Severe Thunderstorm Warning	VEF	Clark	79 min
Jul 21, 10:28 AM PDT	Dust Storm Warning	VEF	Clark	62 min
Jul 21, 12:36 PM PDT	Areal Flood Advisory	VEF	Lincoln	3 hr
Jul 21, 2:28 PM PDT	Severe Thunderstorm Warning	VEF	Clark	62 min

Nearby

Flash Flood Warnings in Nevada, 2018 Every 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.