Alert archive / California / Flash Flood Warnings in 2011

Flash Flood Warning 74, NWS Las Vegas, NV

August 27, 2011San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 27, 2011, 4:31 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 27, 2011, 4:31 PM PDT (23:31 UTC)
Expired
Aug 27, 2011, 6:30 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 Las Vegas radar (KESX), 177 km from the middle of the area, began a volume at 23:35 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, 11.5 hours before the alert went out and 213 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 2011-08-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 46 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 2011-08-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 0 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
46 J/kg
Mixed-layer CIN
-838 J/kg
Mixed-layer LCL
2203 m above ground
0-6 km bulk shear
15 kt
0-1 km storm-relative helicity
0 m²/s²
0-3 km storm-relative helicity
43 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.2

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

448 
WGUS55 KVEF 272331
FFWVEF
CAC071-280130-
/O.NEW.KVEF.FF.W.0074.110827T2331Z-110828T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
431 PM PDT SAT AUG 27 2011

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 630 PM PDT.

* AT 421 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED   
  VERY HEAVY RAIN FROM THUNDERSTORM JUST EAST OF TWENTYNINE PALMS TO 
  AREAS JUST EAST OF AMBOY ROAD...MOVING NORTH AT 10 MPH.

* LOCATIONS IMPACTED INCLUDE...
  HIGHWAY 62 EAST OF TWENTYNINE PALMS AND AMBOY ROAD NORTH TO THE    
  TOWN OF AMBOY.

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 TWITTER #NWSVEGAS.

&&

LAT...LON 3457 11602 3453 11539 3413 11545 3412 11551
      3409 11556 3411 11560 3404 11564 3405 11599

$$

JS
2 follow-up statements
455 
WGUS75 KVEF 280029
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
529 PM PDT SAT AUG 27 2011

CAC071-280130-
/O.CON.KVEF.FF.W.0074.000000T0000Z-110828T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
529 PM PDT SAT AUG 27 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 630 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

AT 519 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED 
THAT MODERATE RAIN CONTINUED OVER THE WARNED AREA.  WATER IN AREA 
WASHES ARE LIKELY TO REMAIN ELEVATED DUE TO THE EARLIER HEAVY RAIN 
AND WATER MAY STILL BE CROSSING AREA ROADWAYS THROUGH 630 PM. 

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 TWITTER #NWSVEGAS.

&&

LAT...LON 3457 11602 3453 11539 3413 11545 3412 11551
      3409 11556 3411 11560 3404 11564 3405 11599

$$

JS
759 
WGUS75 KVEF 280126
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
626 PM PDT SAT AUG 27 2011

CAC071-280134-
/O.EXP.KVEF.FF.W.0074.000000T0000Z-110828T0130Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
626 PM PDT SAT AUG 27 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 630 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

RAIN HAS ENDED IN THE WARNED AREA AND THE WARNING WILL BE ALLOWED TO 
EXPIRE ON TIME. HOWEVER...WASHES MAY REMAIN ELEVEATED AND THERE 
STILL MAY BE PONDING OF WATER ON ROADWAYS. MOTORISTS SHOULD USE 
CAUTION WHEN TRAVELING ROADS IN THE AREA OVER THE NEXT COUPLE OF 
HOURS. 
 
LAT...LON 3457 11602 3453 11539 3413 11545 3412 11551
      3409 11556 3411 11560 3404 11564 3405 11599

$$

JS

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 3:19 AM PDTExcessive Heat WarningVEFInyo, San Bernardino24 hr
Aug 27, 2:01 PM PDTFlash Flood WarningVEFSan Bernardino4 hr
Aug 27, 3:29 PM PDTSevere Thunderstorm WarningVEFSan Bernardino32 min
Aug 27, 4:11 PM PDTSevere Thunderstorm WarningVEFSan Bernardino49 min

Nearby

Flash Flood Warnings in California, 2011Every flash flood warning in 2011

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.