Alert archive / Nevada / Flash Flood Warnings in 2018

Flash Flood Warning 4, NWS Las Vegas, NV

July 9, 2018Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 9, 2018, 8:47 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 9, 2018, 8:47 PM PDT (03:47 UTC)
Expired: Jul 9, 2018, 11:45 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), 66 km from the middle of the area, began a volume at 03:46 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, 3.8 hours before the alert went out and 88 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: 776 J/kg
Mixed-layer CIN: -80 J/kg
Mixed-layer LCL: 3012 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 40 m²/s²
0-3 km storm-relative helicity: 76 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

101 
WGUS55 KVEF 100347
FFWVEF
NVC003-100645-
/O.NEW.KVEF.FF.W.0004.180710T0347Z-180710T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Las Vegas NV
847 PM PDT MON JUL 9 2018

The National Weather Service in Las Vegas has issued a

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

* Until 1145 PM PDT.

* At 845 PM PDT, Doppler radar and automated rain gauges indicated 
  thunderstorms producing heavy rain across the area from Valley of 
  Fire to Callville Bay on Lake Mead. The storms were moving to the 
  southwest at 10 to 15 mph. Flash flooding is expected to begin 
  shortly.

* Some locations that will experience flooding include...
  Valley Of Fire, Callville Bay and Callville Bay Campground. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the
dangers of flooding.

&&

LAT...LON 3613 11448 3613 11451 3614 11450 3615 11451
      3615 11458 3613 11462 3614 11463 3611 11468
      3610 11474 3630 11477 3661 11456 3661 11450
      3644 11442

$$

JA

2 follow-up statements

632 
WGUS75 KVEF 100507
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1007 PM PDT MON JUL 9 2018

NVC003-100645-
/O.CON.KVEF.FF.W.0004.000000T0000Z-180710T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
1007 PM PDT MON JUL 9 2018

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM PDT FOR
NORTHEASTERN CLARK COUNTY...

At 1005 PM PDT, Doppler radar indicated heavy rain had ended over 
the area between Valley of Fire and Callville Bay. However...radar 
rainfall estimates and automated gauges indicated between 1 and 2 
inches of rain fell over parts of the warned area. Flash flooding is 
occurring around Valley of Fire and is expected to begin shortly in 
washes near Callville Bay.

Some locations that will experience flooding include...
Valley Of Fire, Callville Bay and Callville Bay Campground. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Be especially cautious at night when it is harder to recognize the 
dangers of flooding. Avoid washes and low lying areas. Get to higher 
ground.

&&

LAT...LON 3613 11448 3613 11451 3614 11450 3615 11451
      3615 11458 3613 11462 3614 11463 3611 11468
      3610 11474 3630 11477 3661 11456 3661 11450
      3644 11442

$$

964 
WGUS75 KVEF 100643
FFSVEF

Flash Flood Statement
National Weather Service Las Vegas NV
1143 PM PDT MON JUL 9 2018

NVC003-100649-
/O.EXP.KVEF.FF.W.0004.000000T0000Z-180710T0645Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
Clark NV-
1143 PM PDT MON JUL 9 2018

...THE FLASH FLOOD WARNING FOR NORTHEASTERN CLARK COUNTY WILL EXPIRE
AT 1145 PM PDT...

Significant flooding is no longer expected to pose a threat over the 
area between Valley of Fire and Callville Bay since heavy rain ended 
before 9 PM and only light to moderate rainfall remains. Be cautious 
on Valley of Fire Road and North Shore Road for ponding of water in 
low spots and heed any remaining road closures.

LAT...LON 3613 11448 3613 11451 3614 11450 3615 11451
      3615 11458 3613 11462 3614 11463 3611 11468
      3610 11474 3630 11477 3661 11456 3661 11450
      3644 11442

$$

JA

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 9, 6:47 PM PDT	Severe Thunderstorm Warning	VEF	Clark	43 min
Jul 9, 9:21 PM PDT	Severe Thunderstorm Warning	VEF	Clark	54 min
Jul 9, 11:06 PM PDT	Areal Flood Advisory	VEF	Clark	3 hr

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.