Alert archive / California / Flash Flood Warnings in 2011

Flash Flood Warning 75, NWS Las Vegas, NV

August 27, 2011San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 27, 2011, 5:40 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
Aug 27, 2011, 5:40 PM PDT (00:40 UTC)
Expired
Aug 27, 2011, 7:45 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 Las Vegas radar (KESX), 89 km from the middle of the area, began a volume at 00:41 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

Las Vegas, NV (KVEF), launched 00:00Z, 0.7 hours before the alert went out and 148 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 2011-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 78 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 2011-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 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
78 J/kg
Mixed-layer CIN
-155 J/kg
Mixed-layer LCL
3639 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
-7 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.

519 
WGUS55 KVEF 280040
FFWVEF
CAC071-280245-
/O.NEW.KVEF.FF.W.0075.110828T0040Z-110828T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

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

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 745 PM PDT.

* AT 532 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM NEAR MITCHELL CAVERNS. THE
  STORM PRODUCING VERY HEAVY RAIN WAS NEARLY STATIONARY.

* LOCATIONS IMPACTED INCLUDE...
  MITHCELL CAVERNS...HOLE IN THE WALL CAMPGROUND...BLACK CANYON      
  EQUESTRIAN CAMPGROUND...MID HILLS CAMPGROUND AND KELSO CIMA ROAD.

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 TWITTER #NWSVEGAS.

CAMPERS AND HIKERS SHOULD BE ALERT TO THE POSSIBILITY OF RAPIDLY
RISING WATER AND BE PREPARED TO MOVE QUICKLY TO HIGHER GROUND IF
FLASH FLOODING IS OBSERVED.

&&

LAT...LON 3522 11549 3518 11528 3482 11525 3483 11555
      3501 11569

$$

JS
2 follow-up statements
991 
WGUS75 KVEF 280146
FFSVEF

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

CAC071-280245-
/O.CON.KVEF.FF.W.0075.000000T0000Z-110828T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
646 PM PDT SAT AUG 27 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 745 PM PDT FOR
CENTRAL SAN BERNARDINO COUNTY...

AT 635 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE NEARLY STATIONARY STRONG THUNDERSTORMS PRODUCING VERY HEAVY 
RAIN NEAR MITCHELL CAVERNS.

LOCATIONS IMPACTED INCLUDE...
KELSO...HOLE IN THE WALL CAMPGROUND...BLACK CANYON EQUESTRIAN 
CAMPGROUND...MID HILLS CAMPGROUND...MITCHELL CAVERNS AND KELSO CIMA 
ROAD.

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!

CAMPERS AND HIKERS SHOULD BE ALERT TO THE POSSIBILITY OF RAPIDLY 
RISING WATER AND BE PREPARED TO MOVE QUICKLY TO HIGHER GROUND IF 
FLASH FLOODING IS OBSERVED.

REPORT FLOODING BY POSTING YOUR REPORT TO THE LAS VEGAS NATIONAL
WEATHER SERVICE FACEBOOK PAGE OR TWITTER #NWSVEGAS.

&&

LAT...LON 3522 11549 3518 11528 3482 11525 3483 11555
      3501 11569

$$

JS
946 
WGUS75 KVEF 280239
FFSVEF

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

CAC071-280247-
/O.EXP.KVEF.FF.W.0075.000000T0000Z-110828T0245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
739 PM PDT SAT AUG 27 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 745 PM PDT FOR CENTRAL SAN
BERNARDINO COUNTY...

THUNDERSTORMS OVER THE WARNED AREA HAVE WEAKENED. THE FLASH FLOOD 
WARNING WILL EXPIRE AT 745 PM PDT.

LAT...LON 3522 11549 3518 11528 3482 11525 3483 11555
      3501 11569

$$

PIERCE

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 27, 5:20 PM PDTSevere Thunderstorm WarningVEFSan Bernardino40 min
Aug 27, 5:32 PM PDTAreal Flood AdvisoryVEFInyo118 min
Aug 27, 6:33 PM PDTAreal Flood AdvisoryVEFSan Bernardino3 hr
Aug 27, 6:57 PM PDTSevere Thunderstorm WarningVEFSan Bernardino48 min
Aug 28, 3:39 AM PDTExcessive Heat WarningVEFInyo, San Bernardino40 hr
Aug 28, 2:19 PM PDTAreal Flood AdvisoryVEFSan Bernardino52 min
Aug 28, 2:37 PM PDTFlash Flood WarningVEFSan Bernardino113 min
Aug 28, 2:47 PM PDTSevere Thunderstorm WarningVEFSan Bernardino43 min
Aug 28, 4:28 PM PDTFlash Flood WarningVEFSan Bernardino2 hr

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.