Alert archive / Nevada / Flash Flood Warnings in 2012

Flash Flood Warning 199, NWS Las Vegas, NV

September 11, 2012Clark County, Nevada

NWS Las Vegas, NV issued this flash flood warning at Sep 11, 2012, 12:32 PM PDT for Clark County, Nevada. It was in force for 88 min. 2 reports 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
Sep 11, 2012, 12:32 PM PDT (19:32 UTC)
Expired
Sep 11, 2012, 2:00 PM PDT
In force
88 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), 71 km from the middle of the area, began a volume at 19:34 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
Sep 11, 1:00 PM PDTFLASH FLOOD3 N Summerlin, NVA SMALL AMOUNT OF RUNNING WATER MOVED ACROSS LONE MOUNTAIN ROAD JUST EAST OF 215 ALONG WITH MUD AND SMALL ROCKS. THE EVENT TIME IS AN ESTIMATE.
Sep 11, 1:45 PM PDTHEAVY RAIN 02 Ene Summerlin, NVTRAINED SPOTTER REPORTED 10-12 INCHES OF STANDING WATER AT THE INTERSECTION OF EASTERN AND STEWART.

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, 7.5 hours before the alert went out and 25 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 2012-09-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2 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 2012-09-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 17 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
2 J/kg
Mixed-layer CIN
-171 J/kg
Mixed-layer LCL
1725 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
17 m²/s²
0-3 km storm-relative helicity
37 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.

802 
WGUS55 KVEF 111932
FFWVEF
NVC003-112100-
/O.NEW.KVEF.FF.W.0199.120911T1932Z-120911T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
1232 PM PDT TUE SEP 11 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 200 PM PDT.

* AT 1225 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR LONE MOUNTAIN...OR NEAR
  SUMMERLIN. THE STORM PRODUCING VERY HEAVY RAIN WAS NEARLY
  STATIONARY.

* LOCATIONS IMPACTED INCLUDE...
  LONE MOUNTAIN AND SUMMERLIN.

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 3625 11541 3627 11525 3615 11527 3615 11542

$$

JS
3 follow-up statements
065 
WGUS75 KVEF 111954
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1254 PM PDT TUE SEP 11 2012

NVC003-112100-
/O.CON.KVEF.FF.W.0199.000000T0000Z-120911T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
1254 PM PDT TUE SEP 11 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 PM PDT FOR
CENTRAL CLARK COUNTY...

AT 1238 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A THUNDERSTORM PRODUCING VERY HEAVY RAIN OVER THE LONE 
MOUNTAIN AND SUN CITY SUMMERLIN AREA. ONE RAIN GAGE IN THE AREA HAS 
REPORTED 1.18 INCHES OF RAIN IN THE LAST 30 MINUTES. THE 
THUNDERSTORM WITH EXCESSIVE RAIN WAS SLOWLY DRIFTING TO THE EAST AND 
BEGINNING TO IMPACT AREAS EAST OF SUN CITY SUMMERLIN.

LOCATIONS IMPACTED INCLUDE...

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 3625 11541 3627 11525 3615 11527 3615 11542

$$

JS
147 
WGUS75 KVEF 112023
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
123 PM PDT TUE SEP 11 2012

NVC003-112100-
/O.CON.KVEF.FF.W.0199.000000T0000Z-120911T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
123 PM PDT TUE SEP 11 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 200 PM PDT FOR
CENTRAL CLARK COUNTY...

AT 109 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
SECOND STRONG THUNDERSTORM PRODUCING VERY HEAVY RAIN NEAR LONE 
MOUNTAIN. RAIN GAGES IN THE FAR NORTHWEST PORTION OF THE VALLEY WERE 
GENERALLY REPORTING .25 TO .50 INCHES OF RAINFALL HOWEVER...TWO 
GAGES HAVE MEASURED GREATER THAN .80 INCHES IN THE PAST HOUR WITH 
ONE GAGE NEAR THE 215 AND SUMMERLIN PARKWAY REPORTING 1.85 INCHES IN 
THE PAST HOUR. THE THUNDERSTORM WITH EXCESSIVE RAIN WAS DRIFTING 
SLOWLY TO THE EAST.

LOCATIONS IMPACTED INCLUDE...
SUMMERLIN AND LONE MOUNTAIN.

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 3625 11541 3627 11525 3615 11527 3615 11542

$$

JS
535 
WGUS75 KVEF 112055
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
155 PM PDT TUE SEP 11 2012

NVC003-112103-
/O.EXP.KVEF.FF.W.0199.000000T0000Z-120911T2100Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CLARK NV-
155 PM PDT TUE SEP 11 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 200 PM PDT FOR CENTRAL
CLARK COUNTY...

THUNDERSTORMS OVER THE NORTHWEST VALLEY HAVE DISSIPATED AND FLASH 
FLOODING IS NO LONGER A CONCERN IN THIS AREA. HOWEVER...EARLIER 
HEAVY RAIN WILL CONTINUE TO PRODUCE ELEVATED WATER LEVELS IN WASHES 
AND PONDING OF WATER ON ROADWAYS.

LAT...LON 3625 11541 3627 11525 3615 11527 3615 11542

$$

JS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 11, 3:24 AM PDTFlash Flood WarningVEFClark111 min
Sep 11, 4:52 AM PDTFlash Flood WarningVEFNye113 min
Sep 11, 8:28 AM PDTAreal Flood AdvisoryVEFLincoln3 hr
Sep 11, 11:33 AM PDTAreal Flood AdvisoryVEFClark3 hr
Sep 11, 1:44 PM PDTAreal Flood AdvisoryVEFClark27 min
Sep 11, 1:51 PM PDTFlash Flood WarningVEFClark114 min
Sep 11, 2:08 PM PDTFlash Flood WarningVEFClark93 min
Sep 11, 2:16 PM PDTSevere Thunderstorm WarningVEFClark44 min
Sep 11, 2:18 PM PDTFlash Flood WarningVEFClark4 hr
Sep 11, 3:39 PM PDTFlash Flood WarningVEFClark2 hr
Sep 11, 4:02 PM PDTFlash Flood WarningVEFClark118 min

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.