Alert archive / Nevada / Flash Flood Warnings in 2012

Flash Flood Warning 225, NWS Las Vegas, NV

October 11, 2012Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Oct 11, 2012, 10:42 PM PDT for Clark County, Nevada. It was in force for 94 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Oct 11, 2012, 10:42 PM PDT (05:42 UTC)
Expired
Oct 12, 2012, 12:16 AM PDT
In force
94 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), 40 km from the middle of the area, began a volume at 05:42 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, 5.7 hours before the alert went out and 58 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.

636 
WGUS55 KVEF 120542
FFWVEF
NVC003-120745-
/O.NEW.KVEF.FF.W.0225.121012T0542Z-121012T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
1042 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 1245 AM PDT.

* AT 1036 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR HENDERSON...MOVING NORTH
  AT 25 MPH.

* LOCATIONS IMPACTED INCLUDE...
  THE SILVER BOWL...SAM BOYD STADIUM AND EAST LAS VEGAS.

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 3608 11511 3619 11501 3593 11493 3591 11509

$$
CZYZYK
2 follow-up statements
487 
WGUS75 KVEF 120642
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1142 PM PDT THU OCT 11 2012

NVC003-120745-
/O.CON.KVEF.FF.W.0225.000000T0000Z-121012T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
1142 PM PDT THU OCT 11 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1245 AM PDT FOR
CENTRAL CLARK COUNTY...

AT 1136 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THE HEAVY RAIN HAS MOVED TO THE NORTH AND OUT OF THE WARNED AREA. 
RUNOFF WILL LIKELY CONTINUE TO PRODUCE FLOODING THROUGH 1245 AM. 
RAINFALL RATES WITH THE EARLIER STORM WERE AS HIGH AS THREE INCHES 
PER HOUR. 

LOCATIONS IMPACTED INCLUDE...HENDERSON...SAM BOYD STADIUM...AND EAST 
LAS VEGAS.

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 3608 11511 3619 11501 3593 11493 3591 11509

$$

CZYZYK
336 
WGUS75 KVEF 120716
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1216 AM PDT FRI OCT 12 2012

NVC003-120725-
/O.CAN.KVEF.FF.W.0225.000000T0000Z-121012T0745Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
1216 AM PDT FRI OCT 12 2012

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

ALTHOUGH SHOWERS AND THUNDERSTORMS ARE STILL POSSIBLE THE REMAINDER 
OF THE NIGHT ACROSS THE LAS VEGAS VALLEY...HEAVY RAINFALL IS NOT 
BEING EXPERIENCED AT THIS TIME. THUS THE FLASH FLOOD WARNING HAS 
BEEN CANCELLED. 

MOTORISTS SHOULD CONTINUE TO USE EXTRA CAUTION TONIGHT AS PONDING OF 
WATER IN LOW LYING AREAS IS LIKELY TO STILL BE ENCOUNTERED...AND 
AREAS SUSCEPTIBLE TO FLOODING DURING PERIODS OF HEAVY RAIN ARE 
LIKELY STILL SEEING IMPACTS FROM THE EARLIER RAINFALL.

LAT...LON 3608 11511 3619 11501 3593 11493 3591 11509

$$
KENNEDY

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, 7:56 PM PDTFlash Flood WarningVEFClark80 min
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 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.