Alert archive / California / Flash Flood Warnings in 2011

Flash Flood Warning 7, NWS Las Vegas, NV

July 4, 2011San Bernardino County, California

NWS Las Vegas, NV issued this flash flood warning at Jul 4, 2011, 12:43 AM PDT for San Bernardino County, California. It was in force for 62 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: Jul 4, 2011, 12:43 AM PDT (07:43 UTC)
Expired: Jul 4, 2011, 1:45 AM PDT
In force: 62 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), 134 km from the middle of the area, began a volume at 07:43 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, 7.7 hours before the alert went out and 225 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 5387 m above ground
0-6 km bulk shear: 28 kt
0-1 km storm-relative helicity: 49 m²/s²
0-3 km storm-relative helicity: 43 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.

500 
WGUS55 KVEF 040743
FFWVEF
CAC071-040845-
/O.NEW.KVEF.FF.W.0007.110704T0743Z-110704T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LAS VEGAS NV
1243 AM PDT MON JUL 4 2011

THE NATIONAL WEATHER SERVICE IN LAS VEGAS HAS ISSUED A

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

* UNTIL 145 AM PDT.

* AT 1233 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  VERY HEAVY RAIN FROM A THUNDERSTORM OVER EXTREME EAST CENTRAL SAN
  BERNARDINO COUNTY...OR 10 MILES NORTHWEST OF LAKE HAVASU CITY. THE
  STORM PRODUCING VERY HEAVY RAIN WAS NEARLY STATIONARY.

* THE STORM PRODUCING VERY HEAVY RAIN WILL REMAIN OVER MAINLY
  RURAL AREAS OF THE INDICATED COUNTY. HOWEVER THIS WARNING DOES
  INCLUDE THE HAVASU LAKE ROAD FROM HIGHWAY 95 TO HAVASU LAKE
  WITHIN THE CHEMEHUEVI WASH AND ALSO OVER THE CHEMEHUEVI MOUNTAINS.

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS EVEN HARDER TO SEE WATER
COVERING THE ROADWAY OR IN LOW WATER CROSSINGS.

&&

LAT...LON 3454 11463 3468 11461 3465 11446 3461 11443
      3460 11444 3455 11440 3449 11439 3444 11439
      3439 11448 3440 11462

$$

JENSEN

2 follow-up statements

559 
WGUS75 KVEF 040810
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
110 AM PDT MON JUL 4 2011

CAC071-040845-
/O.CON.KVEF.FF.W.0007.000000T0000Z-110704T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
110 AM PDT MON JUL 4 2011

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 145 AM PDT FOR
EXTREME EAST CENTRAL SAN BERNARDINO COUNTY...

AT 1259 AM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO
INDICATE A THUNDERSTORM PRODUCING VERY HEAVY RAIN.  THIS STORM WAS
LOCATED OVER EXTREME EAST CENTRAL SAN BERNARDINO COUNTY...OR 12 MILES
SOUTH OF TOPOCK. THE THUNDERSTORM WITH EXCESSIVE RAIN WAS SLOWLY 
MOVING TO THE NORTH.

THE STORM PRODUCING VERY HEAVY RAIN WILL REMAIN OVER MAINLY RURAL 
AREAS OF THE INDICATED COUNTY. HOWEVER THIS WARNING DOES INCLUDE THE 
HAVASU LAKE ROAD FROM HIGHWAY 95 TO HAVASU LAKE LOCATED WITHIN THE 
CHEMEHUEVI WASH AREA AND ALSO THE CHEMEHUEVI MOUNTAINS.

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.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS EVEN HARDER TO SEE WATER
COVERING THE ROADWAY OR IN LOW WATER CROSSINGS.

&&

LAT...LON 3454 11463 3468 11461 3465 11446 3461 11443
      3460 11444 3455 11440 3449 11439 3444 11439
      3439 11448 3440 11462

$$

JENSEN

033 
WGUS75 KVEF 040842
FFSVEF

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE LAS VEGAS NV
142 AM PDT MON JUL 4 2011

CAC071-040846-
/O.EXP.KVEF.FF.W.0007.000000T0000Z-110704T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
SAN BERNARDINO CA-
142 AM PDT MON JUL 4 2011

...THE FLASH FLOOD WARNING WILL EXPIRE AT 145 AM PDT FOR EXTREME EAST
CENTRAL SAN BERNARDINO COUNTY...

THUNDERSTORMS HAVE DECREASED OVER EXTREME EASTERN SAN BERNARDINO AND 
ALTHOUGH LIGHT RAIN WILL LIKELY BE SEEN THROUGH 3 AM PDT...FLASH 
FLOODING IS NO LONGER EXPECTED.

HOWEVER...THE PREVIOUS HEAVY RAINF WILL LIKELY PRODUCE FLOWING 
WATER IN THE NORMALLY DRY WASHES THROUGHOUT MUCH OF THE NIGHT. 
TRAVELERS ON LAKE HAVASU ROAD FROM INTERSTATE 95 TO THE CITY OF 
HAVASU LAKE...AS WELL AS ALONG INTERSTATE 95 ESPECIALLY BETWEEN MILE 
MARKERS 26 AND 47 SHOULD USE CAUTION OVERNIGHT AS WATER IS 
ESPECIALLY DIFFICULT TO SEE AT NIGHT. 

LAT...LON 3454 11463 3468 11461 3465 11446 3461 11443
      3460 11444 3455 11440 3449 11439 3444 11439
      3439 11448 3440 11462

$$

JENSEN

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 3, 9:59 PM PDT	Severe Thunderstorm Warning	VEF	San Bernardino	46 min
Jul 3, 10:18 PM PDT	Severe Thunderstorm Warning	VEF	San Bernardino	42 min
Jul 4, 4:18 AM PDT	Areal Flood Advisory	VEF	San Bernardino	3 hr
Jul 4, 9:37 AM PDT	Flash Flood Watch	VEF	San Bernardino	11 hr

Nearby

Flash Flood Warnings in California, 2011 Every 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.