Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 86, NWS Las Vegas, NV

July 31, 2012San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 31, 2012, 11:31 PM PDT for San Bernardino County, California. It was in force for 119 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
Jul 31, 2012, 11:31 PM PDT (06:31 UTC)
Expired
Aug 1, 2012, 1:30 AM PDT
In force
119 min
Issued by
NWS Las Vegas, NV
Area
Storm-based polygon
Flood severity
None

County San Bernardino County, CA

What was reported inside it

TimeReportWhereRemark
Jul 31, 11:40 PM PDTFLASH FLOOD1 N Trona, CAESTIMATED 8 TO 12 INCHES OF WATER FLOWING ACROSS TRONA ROAD.

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, 6.5 hours before the alert went out and 170 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 2012-08-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 646 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 2012-08-01The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -12 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
646 J/kg
Mixed-layer CIN
-52 J/kg
Mixed-layer LCL
1370 m above ground
0-6 km bulk shear
8 kt
0-1 km storm-relative helicity
-12 m²/s²
0-3 km storm-relative helicity
16 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.

687 
WGUS55 KVEF 010631
FFWVEF
CAC071-010830-
/O.NEW.KVEF.FF.W.0086.120801T0631Z-120801T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
1131 PM PDT TUE JUL 31 2012

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 130 AM PDT.

* AT 1127 PM PDT...A TRAINED WEATHER SPOTTER REPORTED VERY HEAVY     
  RAIN FROM A THUNDERSTORM NEAR TRONA...OR 20 MILES NORTHEAST OF 
  RIDGECREST. THE STORM WAS MOVING SOUTHWEST AT 20 MPH.

* LOCATIONS IMPACTED INCLUDE...
  MAINLY RURAL AREAS OF NORTHWESTERN SAN BERNARDINO COUNTY INCLUDING
  TRONA AND STATE ROUTE 178.

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 3542 11691 3543 11758 3580 11752 3579 11682

$$

JA
2 follow-up statements
578 
WGUS75 KVEF 010723
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
1223 AM PDT WED AUG 1 2012

CAC071-010830-
/O.CON.KVEF.FF.W.0086.000000T0000Z-120801T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
1223 AM PDT WED AUG 1 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 130 AM PDT FOR
NORTHWESTERN SAN BERNARDINO COUNTY...

TRAINED WEATHER SPOTTERS REPORTED SOME ROADS FLOODED IN TRONA WITH 8 
TO 12 INCHES OF RUNNING WATER. THUNDERSTORMS MOVED SOUTH OF THE AREA 
AND WERE DISSIPATING AND ONLY LIGHT RAIN SHOWERS REMAINED OVER THE 
WARNING AREA. FLOODED ROADS AROUND TRONA CAN STILL BE EXPECTED UNTIL 
130 AM AS RUNOFF FROM THE EARLIER HEAVY RAIN SLOWLY RECEDES.

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 3579 11750 3579 11682 3542 11691 3543 11739

$$

JA
919 
WGUS75 KVEF 010826
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
126 AM PDT WED AUG 1 2012

CAC071-010830-
/O.EXP.KVEF.FF.W.0086.000000T0000Z-120801T0830Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
126 AM PDT WED AUG 1 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 130 AM PDT FOR NORTHWESTERN
SAN BERNARDINO COUNTY...

HEAVY RAIN HAS NOT FALLEN NEAR TRONA SINCE MIDNIGHT AND ONLY LIGHT 
RAIN SHOWERS WERE OCCURRING EARLY THIS MORNING. RUNOFF FROM THE
EARLIER HEAVY RAINFALL HAS LIKELY RECEDED AND THE FLASH FLOOD 
WARNING WILL EXPIRE AT 130 AM.


LAT...LON 3579 11750 3579 11682 3542 11691 3543 11739

$$

JA

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 31, 10:12 PM PDTAreal Flood AdvisoryVEFInyo42 min
Jul 31, 10:51 PM PDTFlash Flood WarningVEFInyo114 min
Aug 1, 2:44 AM PDTFlash Flood WatchVEFSan Bernardino20 hr

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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.