Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 112, NWS Las Vegas, NV

August 12, 2012San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 12, 2012, 2:46 PM PDT for San Bernardino County, California. It was in force for 119 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
Aug 12, 2012, 2:46 PM PDT (21:46 UTC)
Expired
Aug 12, 2012, 4:45 PM PDT
In force
119 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The Santa Ana Mts radar (KSOX), 149 km from the middle of the area, began a volume at 21:47 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

San Diego, CA (KNKX), launched 12:00Z, 9.8 hours before the alert went out and 184 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, San Diego, CA at 12:00Z on 2012-08-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 552 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, San Diego, CA at 12:00Z on 2012-08-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -9 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
552 J/kg
Mixed-layer CIN
-580 J/kg
Mixed-layer LCL
1680 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
-9 m²/s²
0-3 km storm-relative helicity
48 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.

240 
WGUS55 KVEF 122146
FFWVEF
CAC071-122345-
/O.NEW.KVEF.FF.W.0112.120812T2146Z-120812T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
246 PM PDT SUN AUG 12 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTH CENTRAL SAN BERNARDINO COUNTY IN SOUTHERN CALIFORNIA...

* UNTIL 445 PM PDT.

* AT 240 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR TWENTYNINE PALMS. THE
  STORM PRODUCING VERY HEAVY RAIN WAS NEARLY STATIONARY.

* LOCATIONS IMPACTED INCLUDE...
  HIGHWAY 62 NEAR TWENTYNINE PALMS AND TWENTYNINE PALMS.

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 3420 11602 3410 11602 3412 11605 3412 11616
      3420 11616

$$

JS
2 follow-up statements
263 
WGUS75 KVEF 122304
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
404 PM PDT SUN AUG 12 2012

CAC071-122345-
/O.CON.KVEF.FF.W.0112.000000T0000Z-120812T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
404 PM PDT SUN AUG 12 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 445 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

AT 400 PM PDT...THUNDERSTORMS HAVE WEAKENED NEAR TWENTYNINE PALMS 
BUT EARLIER HEAVY RAIN WILL STILL IMPACT HIGHWAY 62 AND LOCAL ROADS 
IN THE VICINITY OF TWENTYNINE PALMS WITH WATER AND DEBRIS OVER 
ROADWAYS. TRAVELERS ALONG HIGHWAY 62 FROM TWENTYNINE PALMS AND WEST 
SHOULD REMAIN ALERT TO FLOODED ROADS AND USE CAUTION IN THE WARNING 
AREA.

LOCATIONS IMPACTED INCLUDE...
TWENTYNINE PALMS AND HIGHWAY 62.

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 3420 11602 3410 11602 3412 11605 3412 11616
      3420 11616

$$

JS
201 
WGUS75 KVEF 122344
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
444 PM PDT SUN AUG 12 2012

CAC071-122352-
/O.EXP.KVEF.FF.W.0112.000000T0000Z-120812T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
444 PM PDT SUN AUG 12 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 445 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

THUNDERSTORMS HAVE ENDED AND FLASH FLOODING IS NOW LONGER EXPECTED 
NEAR TWENTYNINE PALMS. MOTORISTS SHOULD CONTINUE TO USE CAUTION AS 
THEY TRAVEL WEST OF THE TWENTYNINE PALMS AREA ON HIGHWAY 62 DUE TO 
HEAVY RAINFALL AND FLOODING FURTHER WEST.

LAT...LON 3420 11602 3410 11602 3412 11605 3412 11616
      3420 11616

$$

JS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 12, 1:41 PM PDTAreal Flood AdvisoryVEFInyo3 hr
Aug 12, 3:18 PM PDTFlash Flood WarningVEFSan Bernardino117 min

Nearby

Flash Flood Warnings in California, 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.