Alert archive / California / Flash Flood Warnings in 2012

Flash Flood Warning 3, NWS Los Angeles, CA

September 10, 2012Ventura County, California

NWS Los Angeles, CA issued this flash flood warning at Sep 10, 2012, 2:38 PM PDT for Ventura County, California. It was in force for 3 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: Sep 10, 2012, 2:38 PM PDT (21:38 UTC)
Expired: Sep 10, 2012, 5:30 PM PDT
In force: 3 hr
Issued by: NWS Los Angeles, CA
Area: Storm-based polygon
Flood severity: None

County Ventura County, CA

The radar

The Los Angeles radar (KVTX), 35 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

Edwards AFB, CA (KEDW), launched 12:00Z, 9.6 hours before the alert went out and 111 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: 2666 m above ground
0-6 km bulk shear: 13 kt
0-1 km storm-relative helicity: 61 m²/s²
0-3 km storm-relative helicity: 75 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.

341 
WGUS56 KLOX 102138
FFWLOX
CAC111-110030-
/O.NEW.KLOX.FF.W.0003.120910T2138Z-120911T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE OXNARD CA
238 PM PDT MON SEP 10 2012

THE NATIONAL WEATHER SERVICE IN OXNARD HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTH CENTRAL VENTURA COUNTY IN SOUTHWEST CALIFORNIA...

* UNTIL 530 PM PDT

* AT 230 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A 
THUNDERSTORM AROUND THE LOCKWOOD VALLEY AREA. THIS THUNDERSTORM WILL 
BE CAPABLE OF PRODUCING FLASH FLOODING ACROSS BOY SCOUT CAMP ROAD 
AND LOCKWOOD VALLEY ROAD AS WELL AS SEYMOUR CREEK ROAD. RAINFALL 
RATES WERE AROUND ONE TO TWO INCHES PER HOUR. THESE AREAS ARE 
SUSCEPTIBLE FOR ROADWAY FLOODING. 

* THE STORM PRODUCING FLASH FLOODING WILL OTHERWISE REMAIN OVER      
  THE VENTURA COUNTY MOUNTAINS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN HILLY TERRAIN THERE ARE HUNDREDS OF LOW WATER CROSSINGS WHICH ARE
POTENTIALLY DANGEROUS IN HEAVY RAIN. DO NOT ATTEMPT TO TRAVEL ACROSS
FLOODED ROADS. FIND ALTERNATE ROUTES. IT TAKES ONLY A FEW INCHES OF
SWIFTLY FLOWING WATER TO CARRY VEHICLES AWAY.

&&

LAT...LON 3450 11897 3461 11925 3482 11921 3482 11898
      3480 11897 3479 11889 3479 11888 3457 11877

$$

KAPLAN/BOLDT

3 follow-up statements

690 
WGUS76 KLOX 102236
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
336 PM PDT MON SEP 10 2012

CAC111-110030-
/O.CON.KLOX.FF.W.0003.000000T0000Z-120911T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
VENTURA CA-
336 PM PDT MON SEP 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM PDT FOR NORTH
CENTRAL VENTURA COUNTY...

AT 323 PM PDT...NATIONAL WEATHER SERVICE DOPPLER RADAR CONTINUED TO 
INDICATE A THUNDERSTORM JUST SOUTH OF LOCKWOOD VALLEY THAT WAS 
MOVING SLOWLY SOUTH AND DISSIPATING. THERE HAVE BEEN NO REPORTS OF 
FLASH FLOODING ACROSS THE AREA ACCORDING TO VENTURA COUNTY FIRE. 
HOWEVER...SOME STREAMS COULD BE AFFECTED OVER THE NEXT FEW HOURS 
AROUND THE VENTURA COUNTY MOUNTAINS. 

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LOCKWOOD
VALLEY

LAT...LON 3450 11897 3461 11925 3482 11921 3482 11898
      3480 11897 3479 11889 3479 11888 3457 11877

$$

KAPLAN/RAT

635 
WGUS76 KLOX 102335
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
435 PM PDT MON SEP 10 2012

CAC111-110030-
/O.CON.KLOX.FF.W.0003.000000T0000Z-120911T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
VENTURA CA-
435 PM PDT MON SEP 10 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 530 PM PDT FOR NORTH
CENTRAL VENTURA COUNTY...

AT 424 PM PDT...ANOTHER THUNDERSTORM HAS DEVELOPED TO THE WEST OF 
LOCKWOOD VALLEY AND THE THREAT OF FLASH FLOODING WILL CONTINUE TO 
AFFECT SOME OF THE LOW LYING ROADS IN AND AROUND THE LOCKWOOD 
VALLEY. SOME AREAS CAPABLE OF PRODUCING FLASH FLOODING WOULD INCLUDE 
BOY SCOUT CAMP ROAD AND LOCKWOOD VALLEY ROAD AS WELL AS SEYMOUR 
CREEK ROAD. RAINFALL RATES WERE AROUND ONE TO TWO INCHES PER HOUR. 
THESE AREAS ARE SUSCEPTIBLE FOR ROADWAY FLOODING. 

LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO LOCKWOOD
VALLEY

LAT...LON 3450 11897 3461 11925 3482 11921 3482 11898
      3480 11897 3479 11889 3479 11888 3457 11877

$$

KAPLAN/HALL

705 
WGUS76 KLOX 110027
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
527 PM PDT MON SEP 10 2012

CAC111-110033-
/O.EXP.KLOX.FF.W.0003.000000T0000Z-120911T0030Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
VENTURA CA-
527 PM PDT MON SEP 10 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 530 PM PDT FOR NORTH
CENTRAL VENTURA COUNTY...

THE THREAT OF FLASH FLOODING HAS DIMINISHED THIS AFTERNOON ACROSS 
PORTIONS OF THE VENTURA COUNTY MOUNTAINS. LATEST DOPPLER RADAR 
INDICATED A THUNDERSTORM COLLAPSING AROUND 10 MILES SOUTHWEST OF 
LOCKWOOD VALLEY. THUNDERSTORM ACTIVITY SHOULD BEGIN TO DIMINISH AS 
THE HEATING OF THE DAY PASSES.

LAT...LON 3450 11897 3461 11925 3482 11921 3482 11898
      3480 11897 3479 11889 3479 11888 3457 11877

$$

KAPLAN

The office that day

Everything else NWS Los Angeles, CA issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 9, 5:22 PM PDT	Flash Flood Warning	LOX	Los Angeles	3 hr
Sep 9, 6:40 PM PDT	Areal Flood Advisory	LOX		93 min
Sep 10, 3:23 AM PDT	Flash Flood Watch	LOX		16 hr
Sep 10, 2:15 PM PDT	Areal Flood Advisory	LOX		3 hr
Sep 10, 3:40 PM PDT	Flash Flood Warning	LOX	Los Angeles	3 hr
Sep 10, 3:49 PM PDT	Severe Thunderstorm Warning	LOX	Los Angeles	26 min
Sep 10, 4:11 PM PDT	Severe Thunderstorm Warning	LOX	Los Angeles	64 min

Nearby

Flash Flood Warnings in California, 2012 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.