Alert archive / Nevada / Flash Flood Warnings in 2012

Flash Flood Warning 220, NWS Las Vegas, NV

October 11, 2012Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Oct 11, 2012, 7:56 PM PDT for Clark County, Nevada. It was in force for 80 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
Oct 11, 2012, 7:56 PM PDT (02:56 UTC)
Expired
Oct 11, 2012, 9:16 PM PDT
In force
80 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), 49 km from the middle of the area, began a volume at 02:58 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
Oct 11, 8:50 PM PDTFLASH FLOOD4 Wnw Silverado Ranch, NVAT LEAST 6 INCHES OF FLOWING WATER WAS CROSSING THE SOUTHBOUND LANE OF DEAN MARTIN DRIVE.

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 00:00Z, 2.9 hours before the alert went out and 46 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 00:00Z on 2012-10-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 305 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 00:00Z on 2012-10-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 56 square meters per square second.1939587897Sfc1 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
305 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
1141 m above ground
0-6 km bulk shear
64 kt
0-1 km storm-relative helicity
56 m²/s²
0-3 km storm-relative helicity
58 m²/s²
Significant tornado parameter
0.1
Supercell composite
1.3

Open this sounding in Storm Lab

The text

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

593 
WGUS55 KVEF 120256
FFWVEF
NVC003-120500-
/O.NEW.KVEF.FF.W.0220.121012T0256Z-121012T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
756 PM PDT THU OCT 11 2012

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 750 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  AN AREA OF THUNDERSTORMS MOVING NORTHWEST AT 10 TO 15 MPH ACROSS   
  THE SOUTHWEST AND SOUTH END OF THE LAS VEGAS VALLEY. VERY HEAVY    
  RAIN WAS FALLING WITH THIS AREA OF THUNDERSTORMS WITH LOCALIZED       
  AMOUNTS LIKELY TO EXCEED A HALF AN INCH AN HOUR. POOR DRAINAGE     
  AREAS AND LOW LYING SECTIONS WILL SEE SEVERAL INCHES OF WATER      
  FLOWING THROUGH THEM AS WELL AS THE POTENTIAL FOR MUD AND ROCKS TO 
  ACCOMPANY THE WATER. BE CAREFUL AT NIGHT AS IT IS HARDER TO SEE    
  FLOODWATERS. WASHES WILL SEE RAPID FLOWS IN THEM. 

* LOCATIONS IMPACTED INCLUDE...
  HENDERSON EXECUTIVE...ANTHEM...SLOAN...SEVEN HILLS...SOUTHERN
  HIGHLANDS...SILVERADO RANCH...GREEN VALLEY...MOUNTAINS EDGE...
  MCCARRAN INTERNATIONAL AIRPORT AND SPRING 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 3616 11537 3607 11507 3585 11499 3597 11537

$$

STACHELSKI
1 follow-up statement
320 
WGUS75 KVEF 120416
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
916 PM PDT THU OCT 11 2012

NVC003-120420-
/O.CAN.KVEF.FF.W.0220.000000T0000Z-121012T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
916 PM PDT THU OCT 11 2012

...THE FLASH FLOOD WARNING HAS BEEN CANCELLED FOR CENTRAL CLARK
COUNTY...

THE HEAVY RAIN HAS ENDED ACROSS THE SOUTHERN AND SOUTHWEST PORTION 
OF THE LAS VEGAS VALLEY. RUNOFF WILL CONTINUE TO PRODUCE MINOR 
FLOODING...BUT THE MOST SIGNIFICANT FLOODING HAS ENDED AND THE FLASH 
FLOOD WARNING HAS BEEN CANCELLED. ADDITIONAL FLASH FLOOD WARNINGS 
STILL REMAIN IN EFFECT IN CENTRAL CLARK COUNTY FURTHER TO THE NORTH 
INCLUDING LOCATIONS OF NORTH LAS VEGAS... NELLIS AFB...AND ALIANTE. 

LAT...LON 3616 11537 3607 11507 3585 11499 3597 11537

$$

CZYZYK

The office that day

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

IssuedProductOfficeCountiesLasted
Oct 11, 5:25 PM PDTSevere Thunderstorm WarningVEFClark, Nye35 min
Oct 11, 5:52 PM PDTSevere Thunderstorm WarningVEFNye53 min
Oct 11, 6:45 PM PDTFlash Flood WarningVEFClark2 hr
Oct 11, 8:12 PM PDTSevere Thunderstorm WarningVEFClark48 min
Oct 11, 8:21 PM PDTFlash Flood WarningVEFClark114 min
Oct 11, 8:57 PM PDTSevere Thunderstorm WarningVEFClark48 min
Oct 11, 9:07 PM PDTFlash Flood WarningVEFClark113 min
Oct 11, 9:40 PM PDTSevere Thunderstorm WarningVEFClark27 min
Oct 11, 10:15 PM PDTFlash Flood WarningVEFClark2 hr
Oct 11, 10:42 PM PDTFlash Flood WarningVEFClark94 min
Oct 12, 12:03 AM PDTFlash Flood WarningVEFNye87 min
Oct 12, 12:28 AM PDTSevere Thunderstorm WarningVEFLincoln32 min
Oct 12, 1:43 PM PDTFlash Flood WarningVEFClark2 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.