Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 182, NWS Las Vegas, NV

September 4, 2012San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Sep 4, 2012, 3:44 PM PDT for San Bernardino County, California. It was in force for 2 hr. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 4, 2012, 3:44 PM PDT (22:44 UTC)
Expired
Sep 4, 2012, 5:45 PM PDT
In force
2 hr
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

The radar

The San Diego radar (KNKX), 187 km from the middle of the area, began a volume at 22:46 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

Yuma Intl Airpor, AZ (KYUM), launched 12:00Z, 10.7 hours before the alert went out and 187 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, Yuma Intl Airpor, AZ at 12:00Z on 2012-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 907 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, Yuma Intl Airpor, AZ at 12:00Z on 2012-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 2 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
907 J/kg
Mixed-layer CIN
-175 J/kg
Mixed-layer LCL
1469 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
2 m²/s²
0-3 km storm-relative helicity
12 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.

232 
WGUS55 KVEF 042244
FFWVEF
CAC071-050045-
/O.NEW.KVEF.FF.W.0182.120904T2244Z-120905T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
344 PM PDT TUE SEP 4 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 545 PM PDT.

* AT 336 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM OVER EXTREME SOUTH CENTRAL SAN
  BERNARDINO COUNTY...OR 25 MILES EAST OF TWENTYNINE PALMS. THE STORM
  PRODUCING VERY HEAVY RAIN WAS NEARLY STATIONARY.

* LOCATIONS IMPACTED INCLUDE...
  HIGHWAY 62 BETWEEN MILE MARKERS 54 AND 68...OTHERWISE MAINLY RURAL 
  AREAS OF SOUTHERN SAN BERNARDINO COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED IN WASHES...LOW WATER CROSSINGS AND ON
AREA ROADWAYS. FLASH FLOODING IS NATURES NUMBER ONE KILLER. TO ESCAPE
RISING WATER...MOVE TO HIGHER GROUND. 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 3416 11573 3419 11549 3411 11548 3411 11553
      3408 11556 3410 11560 3407 11561 3404 11560
      3404 11573

$$

JS
2 follow-up statements
670 
WGUS75 KVEF 042350
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
450 PM PDT TUE SEP 4 2012

CAC071-050045-
/O.CON.KVEF.FF.W.0182.000000T0000Z-120905T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
450 PM PDT TUE SEP 4 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 545 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

AT 441 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR SHOWED  
THUNDERSTORM ACTIVITY HAD ENDED IN THE WARNED AREA. HOWEVER... 
RUNOFF FROM THE EARLIER STORM COULD STILL BE AFFECTING AREAS WHERE 
WASHES CROSS HIGHWAY 62 BETWEEN MILE MARKERS 54 AND 63. 

LOCATIONS IMPACTED INCLUDE...
MAINLY RURAL AREAS OF SOUTHERN SAN BERNARDINO COUNTY.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FLASH FLOODING IS EXPECTED IN WASHES...LOW WATER CROSSINGS AND ON
AREA ROADWAYS. FLASH FLOODING IS NATURES NUMBER ONE KILLER. TO ESCAPE
RISING WATER...MOVE TO HIGHER GROUND. 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 3416 11573 3419 11549 3411 11548 3411 11553
      3408 11556 3410 11560 3407 11561 3404 11560
      3404 11573

$$

JS
335 
WGUS75 KVEF 050049
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
549 PM PDT TUE SEP 4 2012

CAC071-050055-
/O.EXP.KVEF.FF.W.0182.000000T0000Z-120905T0045Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
549 PM PDT TUE SEP 4 2012

...THE FLASH FLOOD WARNING HAS EXPIRED FOR SOUTH CENTRAL SAN
BERNARDINO COUNTY...

THUNDERSTORMS HAVE MOVED OUT OF THE AREA AND FLASH FLOODING IS NO 
LONGER EXPECTED. MOTORISTS TRAVELING ALONG HIGHWAY 62 EAST OF 
TWENTYNINE PALMS SHOULD BE ALERT TO WATER AND DEBRIS LEFT ON THE 
ROADWAY BY EARLIER HEAVY RAIN. 

LAT...LON 3416 11573 3419 11549 3411 11548 3411 11553
      3408 11556 3410 11560 3407 11561 3404 11560
      3404 11573

$$

JS

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 3, 6:08 PM PDTSevere Thunderstorm WarningVEFSan Bernardino37 min
Sep 3, 6:43 PM PDTAreal Flood AdvisoryVEFSan Bernardino63 min
Sep 3, 7:42 PM PDTFlash Flood WarningVEFSan Bernardino3 hr
Sep 4, 2:00 PM PDTFlash Flood WarningVEFSan Bernardino65 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.