Alert archive / California / Flash Flood Warnings in 2011

Flash Flood Warning 78, NWS Las Vegas, NV

August 28, 2011San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Aug 28, 2011, 2:37 PM PDT for San Bernardino County, California. It was in force for 113 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 28, 2011, 2:37 PM PDT (21:37 UTC)
Expired
Aug 28, 2011, 4:30 PM PDT
In force
113 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), 131 km from the middle of the area, began a volume at 21:40 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, 9.6 hours before the alert went out and 172 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 2011-08-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 19 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 2011-08-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -42 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
19 J/kg
Mixed-layer CIN
-740 J/kg
Mixed-layer LCL
2184 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
-42 m²/s²
0-3 km storm-relative helicity
33 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.

887 
WGUS55 KVEF 282137
FFWVEF
CAC071-282330-
/O.NEW.KVEF.FF.W.0078.110828T2137Z-110828T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
237 PM PDT SUN AUG 28 2011

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 430 PM PDT.

* AT 231 PM PDT...LOCAL LAW ENFORCEMENT OFFICIALS REPORTED VERY HEAVY
  RAIN FROM A THUNDERSTORM NEAR JOSHUA TREE...OR 12 MILES WEST OF
  TWENTYNINE PALMS. THE STORM PRODUCING VERY HEAVY RAIN WAS NEARLY   
  STATIONARY. 

* LOCATIONS IMPACTED INCLUDE...
  HIGHWAY 62 NEAR JOSHUA TREE.

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.

&&

LAT...LON 3408 11637 3425 11639 3425 11617 3413 11615
      3412 11620 3412 11626 3410 11627

$$

JS
2 follow-up statements
208 
WGUS75 KVEF 282241
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
341 PM PDT SUN AUG 28 2011

CAC071-282330-
/O.CON.KVEF.FF.W.0078.000000T0000Z-110828T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
341 PM PDT SUN AUG 28 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

AT 329 PM PDT...REPORTS OF FLASH FLOODING WERE RECEIVED BY THE FIRE 
DEPARTMENT...LOCAL LAW ENFORECMENT AND TRAINED WEATHER SPOTTERS 
ALONG HIGHWAY 62 NEAR JOSHUA TREE. IN ADDITION...EARLIER STORMS WERE 
PRODUCING HEAVY RAIN NEAR HIGHWAY 247 AND LOCALIZED FLOODING WAS 
LIKELY OCCURRING THERE. THE THUNDERSTORMS THAT PRODUCED THE 
EXCESSIVE RAIN HAVE WEAKENED CONSIDERABLY BUT FLOODING CONDITIONS 
ARE POSSIBLE THROUGH AT LEAST 430 PM.

LOCATIONS IMPACTED INCLUDE...
JOSHUA TREE LAKE CAMPGROUND.

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.

&&

LAT...LON 3408 11637 3425 11639 3425 11617 3413 11615
      3412 11620 3412 11626 3410 11627

$$

JS
948 
WGUS75 KVEF 282322
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
422 PM PDT SUN AUG 28 2011

CAC071-282330-
/O.EXP.KVEF.FF.W.0078.000000T0000Z-110828T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
422 PM PDT SUN AUG 28 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 430 PM PDT FOR SOUTH
CENTRAL SAN BERNARDINO COUNTY...

AT 420 PM PDT...RADAR INDICATED THAT RAIN HAD ENDED IN JOSHUA TREE. 
NO REPORTS OF FLOODING HAD BEEN RECEIVED SINCE 3 PM...SO THE FLASH 
FLOOD WARNING WILL BE ALLOWED TO EXPIRE.

LAT...LON 3408 11637 3425 11639 3425 11617 3413 11615
      3412 11620 3412 11626 3410 11627

$$

MORGAN

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, 5:40 PM PDTFlash Flood WarningVEFSan Bernardino2 hr
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, 2:47 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.