Alert archive / Nevada / Flash Flood Warnings in 2012

Flash Flood Warning 84, NWS Las Vegas, NV

July 31, 2012Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Jul 31, 2012, 4:37 PM PDT for Clark County, Nevada. It was in force for 113 min. 1 report came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Jul 31, 2012, 4:37 PM PDT (23:37 UTC)
Expired
Jul 31, 2012, 6:30 PM PDT
In force
113 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County Clark County, NV

The radar

The Las Vegas radar (KESX), 37 km from the middle of the area, began a volume at 23:40 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.

What was reported inside it

TimeReportWhereRemark
Jul 31, 5:10 PM PDTFLASH FLOOD5 Ese Henderson, NVLAS VEGAS BROADCAST MEDIA REPORTED AT LEAST 6 INCHES OF MUDDY FLOWING WATER AT THE INTERSECTION WAGON WHEEL AND BOULDER HIGHWAY.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Las Vegas, NV (KVEF), launched 12:00Z, 11.6 hours before the alert went out and 63 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 2012-07-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 121 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 2012-07-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
121 J/kg
Mixed-layer CIN
-75 J/kg
Mixed-layer LCL
1334 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
-43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

718 
WGUS55 KVEF 312337
FFWVEF
NVC003-010130-
/O.NEW.KVEF.FF.W.0084.120731T2337Z-120801T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
437 PM PDT TUE JUL 31 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  CENTRAL CLARK COUNTY IN SOUTHERN NEVADA...

* UNTIL 630 PM PDT.

* AT 432 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR RAILROAD PASS...OR NEAR
  BOULDER CITY...MOVING NORTHWEST AT 5 MPH.

* LOCATIONS IMPACTED INCLUDE...
  HENDERSON AND GREEN VALLEY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED ON AREA ROADWAYS...AROUND UNDERPASSES...
AND IN NORMALLY DRY WASHES AND LOW LYING AREAS. FLASH FLOODING IS
NATURES NUMBER ONE KILLER. NEVER TRY TO CROSS A FLOODED ROADWAY OR
WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE...OR BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3604 11511 3616 11491 3599 11485 3591 11496

$$

JA
3 follow-up statements
848 
WGUS75 KVEF 312358
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
458 PM PDT TUE JUL 31 2012

NVC003-010130-
/O.CON.KVEF.FF.W.0084.000000T0000Z-120801T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
458 PM PDT TUE JUL 31 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM PDT FOR
CENTRAL CLARK COUNTY...

DOPPLER RADAR INDICATED A THUNDERSTORM PRODUCING HEAVY RAIN OVER 
HENDERSON. THIS STORM WAS MOVING TO THE NORTHWEST AT 5 MPH.
AUTOMATED SENSORS IN HENDERSON REPORTED BETWEEN THREE-QUARTERS
OF AN INCH AND 1.3 INCHES OF RAIN HAVE FALLEN IN THIRTY MINUTES.

LOCATIONS IMPACTED INCLUDE...
HENDERSON...GREEN VALLEY...RAILROAD PASS AND AREAS AROUND SAM BOYD 
STADIUM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED ON AREA ROADWAYS...AROUND UNDERPASSES...
AND IN NORMALLY DRY WASHES AND LOW LYING AREAS. FLASH FLOODING IS
NATURES NUMBER ONE KILLER. NEVER TRY TO CROSS A FLOODED ROADWAY OR
WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE...OR BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3604 11511 3616 11491 3599 11485 3591 11496

$$

JA
918 
WGUS75 KVEF 010023
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
523 PM PDT TUE JUL 31 2012

NVC003-010130-
/O.CON.KVEF.FF.W.0084.000000T0000Z-120801T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
523 PM PDT TUE JUL 31 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM PDT FOR
CENTRAL CLARK COUNTY...

AT 515 PM PDT...FLASH FLOODING WAS REPORTED NEAR WAGON WHEEL DRIVE 
AND BOULDER HIGHWAY IN HENDERSON. THE THUNDERSTORM WAS WEAKENING AND 
ONLY LIGHT TO MODERATE RAIN SHOWERS WERE OCCURRING. AUTOMATED RAIN 
GAUGES AROUND WAGON WHEEL AND BOULDER HIGHWAY REPORTED RAINFALL 
AMOUNTS BETWEEN .75 OF AN INCH AND 1.3 INCHES SINCE 520 PM.

LOCATIONS IMPACTED INCLUDE...
HENDERSON FROM WAGON WHEEL DRIVE TO SAM BOYD STADIUM.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED ON AREA ROADWAYS...AROUND UNDERPASSES...
AND IN NORMALLY DRY WASHES AND LOW LYING AREAS. FLASH FLOODING IS
NATURES NUMBER ONE KILLER. NEVER TRY TO CROSS A FLOODED ROADWAY OR
WALK THROUGH FLOODWATERS. TURN AROUND...DONT DROWN!

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE...OR BY USING THE TWITTER HASHTAG...
NWSVEGAS.

&&

LAT...LON 3594 11492 3607 11505 3616 11491 3599 11485

$$

JA
425 
WGUS75 KVEF 010126 RRA
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
626 PM PDT TUE JUL 31 2012

NVC003-010131-
/O.EXP.KVEF.FF.W.0084.000000T0000Z-120801T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
626 PM PDT TUE JUL 31 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 630 PM PDT FOR CENTRAL
CLARK COUNTY...

NO ADDITIONAL RAIN HAS FALLEN OVER HENDERSON SINCE 530 PM. EVEN 
THOUGH THE FLASH FLOOD WARNING WILL BE ALLOWED TO EXPIRE ON 
SCHEDULE...RUNOFF WILL STILL BE RECEDING IN FLOOD CHANNELS AND ON 
SOME STREETS AND INTERSECTIONS THROUGH EARLY EVENING.

LAT...LON 3594 11492 3607 11505 3616 11491 3599 11485

$$

JA

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 2:29 AM PDTFlash Flood WatchVEFClark19 hr
Jul 31, 6:39 AM PDTAreal Flood AdvisoryVEFClark51 min
Jul 31, 2:33 PM PDTFlash Flood WarningVEFClark, Nye117 min
Jul 31, 2:42 PM PDTFlash Flood WarningVEFClark3 hr

Nearby

Flash Flood Warnings in Nevada, 2012Every flash flood warning in 2012

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.