Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 118, NWS Las Vegas, NV

August 17, 2012San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 17, 2012, 2:48 PM PDT for San Bernardino County, California. It was in force for 102 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
Aug 17, 2012, 2:48 PM PDT (21:48 UTC)
Expired
Aug 17, 2012, 4:30 PM PDT
In force
102 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), 136 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.

What was reported inside it

TimeReportWhereRemark
Aug 17, 2:50 PM PDTHEAVY RAIN 0.53 Ese Joshua Tree, CASPOTTER REPORTS AN ESTIMATED HALF INCH OF RAIN FELL IN A 10 MINUTE PERIOD ENDING AT 1450 PDT.
Aug 17, 4:30 PM PDTHEAVY RAIN 1.252 Sw Twentynine Palms, CA1.25 INCES OF RAIN FELL IN A 40 MINUTE PERIOD. SPOTTER REPORTS 2 INCHES OF WATER FLOWING ACROSS ADOBE ROAD IN TWENTYNINE PALMS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Edwards AFB, CA (KEDW), launched 12:00Z, 9.8 hours before the alert went out and 169 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, Edwards AFB, CA at 12:00Z on 2012-08-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Edwards AFB, CA at 12:00Z on 2012-08-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -3 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3028 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-3 m²/s²
0-3 km storm-relative helicity
92 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.

931 
WGUS55 KVEF 172148
FFWVEF
CAC071-172345-
/O.NEW.KVEF.FF.W.0118.120817T2148Z-120817T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
248 PM PDT FRI AUG 17 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 235 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
VERY HEAVY RAIN FROM A THUNDERSTORM NEAR JOSHUA TREE...OR 2 MILES 
EAST OF YUCCA VALLEY THE STORM PRODUCING VERY HEAVY RAIN WAS   
NEARLY STATIONARY.

* LOCATIONS IMPACTED INCLUDE...ROUTE 62 FROM TWENTYNINE PALMS TO 
JOSHUA TREE AND WEST ALONG ROUTE 62 TO AVALON AVENUE TOWARDS YUCCA 
VALLEY.

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 3418 11638 3419 11603 3411 11604 3411 11605
      3412 11606 3412 11626 3408 11627 3408 11639

$$

KENNEDY
2 follow-up statements
788 
WGUS75 KVEF 172231
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
331 PM PDT FRI AUG 17 2012

CAC071-172345-
/O.CON.KVEF.FF.W.0118.000000T0000Z-120817T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
331 PM PDT FRI AUG 17 2012

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

AT 320 PM PDT...HEAVY RAIN HAD LARGELY SUBSIDED BETWEEN TWENTYNINE 
PALMS AND YUCCA VALLEY...HOWEVER...A TRAINED STORM SPOTTER IN JOSHUA 
TREE REPORTED 0.50 INCHES OF RAIN FELL IN 10 MINUTES...WHICH 
COINCIDES WELL WITH RADAR PRECIPITATION ESTIMATES. RADAR ESTIMATES 
SHOW UP TO 2 INCHES OF RAINFALL ACROSS BASINS JUST SOUTH OR ROUTE 62 
WHICH ALL FLOW NORTH TOWARDS THE ROADWAY AND WILL LIKELY IMPACT 
KNOWN LOW WATER CROSSINGS ALONG ROUTE 62 SUCH AS MILE 
SQUARE...SUNBURST...SUNNY VISTA...AND YUCCA MESA ROADS.

LOCATIONS IMPACTED INCLUDE...ROUTE 62 FROM TWENTYNINE PALMS TO 
JOSHUA TREE AND WEST ALONG ROUTE 62 TO AVALON AVENUE TOWARDS YUCCA 
VALLEY.

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 3418 11638 3419 11603 3411 11604 3411 11605
      3412 11606 3412 11626 3408 11627 3408 11639

$$
KENNEDY
385 
WGUS75 KVEF 172330
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
430 PM PDT FRI AUG 17 2012

CAC071-172339-
/O.CAN.KVEF.FF.W.0118.000000T0000Z-120817T2345Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
430 PM PDT FRI AUG 17 2012

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

LAT...LON 3418 11638 3419 11603 3411 11604 3411 11605
      3412 11606 3412 11626 3408 11627 3408 11639

NO SIGNIFICANT RAINFALL HAS BEEN OBSERVED BETWEEN YUCCA VALLEY AND 
TWENTYNINE PALMS FOR THE PAST 50 MINUTES...AND ANY WATER FLOWING IN 
NORMALLY DRY WASHES OR IMPACTING ANY LOW WATER CROSSING SHOULD BE 
SUBSIDING. THEREFORE...THE FLASH FLOOD WARNING IS CANCELLED. 

$$
KENNEDY

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 17, 11:23 AM PDTFlash Flood WatchVEFSan Bernardino8 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; radar from the NEXRAD Level II archive.