Alert archive / California / Flash Flood Warnings in 2015

Flash Flood Warning 21, NWS Los Angeles, CA

July 30, 2015Los Angeles County, California

NWS Los Angeles, CA issued this flash flood warning at Jul 30, 2015, 2:29 PM PDT for Los Angeles 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
Jul 30, 2015, 2:29 PM PDT (21:29 UTC)
Expired
Jul 30, 2015, 4:30 PM PDT
In force
2 hr
Issued by
NWS Los Angeles, CA
Area
Storm-based polygon
Flood severity
None

County Los Angeles County, CA

The radar

The Los Angeles radar (KVTX), 78 km from the middle of the area, began a volume at 21:29 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

Vandenberg AFB, CA (KVBG), launched 12:00Z, 9.5 hours before the alert went out and 200 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, Vandenberg AFB, CA at 12:00Z on 2015-07-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Vandenberg AFB, CA at 12:00Z on 2015-07-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 56 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1641 m above ground
0-6 km bulk shear
5 kt
0-1 km storm-relative helicity
56 m²/s²
0-3 km storm-relative helicity
99 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.

336 
WGUS56 KLOX 302131
FFWLOX
CAC037-302330-
/O.NEW.KLOX.FF.W.0021.150730T2129Z-150730T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE OXNARD CA
229 PM PDT THU JUL 30 2015

THE NATIONAL WEATHER SERVICE IN OXNARD HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  NORTH CENTRAL LOS ANGELES COUNTY IN SOUTHWESTERN CALIFORNIA...

* UNTIL 430 PM PDT
    
* AT 229 PM PDT...DOPPLER RADAR INDICATED A THUNDERSTORM PRODUCING
  HEAVY RAIN ACROSS THE WARNED AREA. FLASH FLOODING IS EXPECTED TO 
  BEGIN SHORTLY. ANY THUNDERSTORM THAT FORMS WILL BE CAPABLE OF 
  PRODUCING DANGEROUS CLOUD TO GROUND LIGHTNING...SMALL HAIL AND 
  STRONG GUSTY WINDS.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...ACTON... 
  SANTA CLARITA...HIGHWAY 14 AND THE POWERHOUSE BURN AREA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

TURN AROUND...DONT DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 3428 11822 3437 11851 3456 11864 3471 11852
      3482 11830 3457 11794

$$

CS/RK/DG
2 follow-up statements
798 
WGUS76 KLOX 302229
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
319 PM PDT THU JUL 30 2015

CAC037-302330-
/O.CON.KLOX.FF.W.0021.000000T0000Z-150730T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOS ANGELES CA-
319 PM PDT THU JUL 30 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 430 PM PDT FOR
NORTH CENTRAL LOS ANGELES COUNTY...

AT 319 PM PDT...DOPPLER RADAR CONTINUED TO INDICATE THUNDERSTORMS 
PRODUCING HEAVY RAIN ACROSS THE WARNED AREA. LOCAL GAGES SHOW 
RAINFALL TOTALS UP TO ONE AND ONE QUARTER INCHES OF RAIN...AND 
DOPPLER RADAR ESIMATES UP TO TWO INCHES OF RAIN OVER HIGHWAY 14 WEST 
OF ACTON. CALIFORNIA HIGHWAY PATROL HAS REPORTED HEAVY MUD AND 
FLOODING ON HIGHWAY 14 BETWEEN ESCONDIDO AND RED ROVER MINE ROAD. 

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING IF THEY HAVE NOT 
ALREADY INCLUDE...ACTON... SANTA CLARITA...HIGHWAY 14 AND THE 
POWERHOUSE BURN AREA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

MOVE TO HIGHER GROUND NOW. ACT QUICKLY TO PROTECT YOUR LIFE.

TURN AROUND...DONT DROWN WHEN ENCOUNTERING FLOODED ROADS. MOST FLOOD
DEATHS OCCUR IN VEHICLES.

&&

LAT...LON 3428 11822 3437 11851 3456 11864 3471 11852
      3482 11830 3457 11794

$$

SMITH/GOMBERG
256 
WGUS76 KLOX 302338
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
436 PM PDT THU JUL 30 2015

CAC037-302346-
/O.EXP.KLOX.FF.W.0021.000000T0000Z-150730T2330Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOS ANGELES CA-
436 PM PDT THU JUL 30 2015

...THE FLASH FLOOD WARNING FOR NORTH CENTRAL LOS ANGELES COUNTY HAS
EXPIRED...

THE HEAVY RAIN HAS ENDED...BUT ADDITIONAL STORMS ARE STARTING TO 
FORM IN THE WARNING AREA EAST OF ACTON. ANY THUNDERSTORMS THAT 
DEVELOP IN THIS AREA WILL BE CAPABLE OF PRODUCING HEAVY 
RAIN...LIGHTNING...STRONG GUSTY WINDS...HAIL...AND ROADWAY FLOODING. 

LAT...LON 3428 11822 3437 11851 3456 11864 3471 11852
      3482 11830 3457 11794

$$

SMITH/GOMBERG

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 29, 5:43 PM PDTFlash Flood WarningLOXLos Angeles107 min
Jul 29, 9:07 PM PDTFlash Flood WatchLOXLos Angeles, Santa Barbara25 hr
Jul 30, 11:49 AM PDTFlash Flood WarningLOXSanta Barbara, Ventura3 hr
Jul 30, 1:29 PM PDTAreal Flood AdvisoryLOXLos Angeles3 hr
Jul 30, 1:48 PM PDTFlash Flood WarningLOXLos Angeles, Ventura3 hr
Jul 30, 1:50 PM PDTFlash Flood WarningLOXLos Angeles3 hr
Jul 30, 2:47 PM PDTFlash Flood WarningLOXSanta Barbara3 hr
Jul 30, 2:47 PM PDTFlash Flood WarningLOXLos Angeles, Ventura3 hr
Jul 30, 3:09 PM PDTFlash Flood WarningLOXLos Angeles3 hr
Jul 30, 3:12 PM PDTSevere Thunderstorm WarningLOXLos Angeles, Ventura48 min
Jul 30, 3:52 PM PDTSevere Thunderstorm WarningLOXVentura53 min
Jul 30, 3:55 PM PDTFlash Flood WarningLOXVentura3 hr

Nearby

Flash Flood Warnings in California, 2015Every flash flood warning in 2015

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.