Alert archive / California / Flash Flood Warnings in 2015

Flash Flood Warning 13, NWS Los Angeles, CA

July 19, 2015Los Angeles County, California

NWS Los Angeles, CA issued this flash flood warning at Jul 19, 2015, 5:10 PM PDT for Los Angeles County, California. It was in force for 5 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 19, 2015, 5:10 PM PDT (00:10 UTC)
Expired: Jul 19, 2015, 10:00 PM PDT
In force: 5 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), 69 km from the middle of the area, began a volume at 00:13 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 00:00Z, 0.2 hours before the alert went out and 186 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: 106 J/kg
Mixed-layer CIN: -116 J/kg
Mixed-layer LCL: 1064 m above ground
0-6 km bulk shear: 23 kt
0-1 km storm-relative helicity: 102 m²/s²
0-3 km storm-relative helicity: 72 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.

997 
WGUS56 KLOX 200010
FFWLOX
CAC037-200300-
/O.NEW.KLOX.FF.W.0013.150720T0010Z-150720T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE OXNARD CA
510 PM PDT SUN JUL 19 2015

THE NATIONAL WEATHER SERVICE IN OXNARD HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  THE POWERHOUSE BURN AREA IN NORTHWESTERN LOS ANGELES COUNTY IN 
  SOUTHWESTERN CALIFORNIA...

* UNTIL 800 PM PDT

* AT 507 PM PDT...DOPPLER RADAR INDICATED HEAVY RAIN ACROSS THE 
  WARNED AREA WITH HOURLY RAINFALL RATES UP TO 2 INCHES PER HOUR.  
  FLASH FLOODING IS EXPECTED TO BEGIN SHORTLY...PRODUCING 
  SIGNIFICANT MUD AND DEBRIS FLOWS IN THE BURN AREA. 

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...ELIZABETH 
  LAKE...CASTAIC LAKE...HIGHWAY 138 BETWEEN QUAIL LAKE AND THE 
  POWERHOUSE BURN AREA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A FLASH FLOOD WARNING FOR A RECENT BURN AREA MEANS THAT FLOODING AND
DEBRIS FLOWS ARE IMMINENT OR OCCURRING. RESIDENTS LIVING IN OR
IMMEDIATELY DOWNSTREAM SHOULD TAKE IMMEDIATE PRECAUTIONS TO PROTECT
LIFE AND PROPERTY. QUICKLY MOVE AWAY FROM THE BURN AREA ONLY IF IT IS
SAFE TO DO SO...OTHERWISE SHELTER IN PLACE AND MOVE TO A SECOND STORY
OR THE HIGHEST LOCATION IN YOUR HOME TO STAY OUT OF THE PATH OF
FAST-MOVING WATER AND DEBRIS FLOWS.

&&

LAT...LON 3442 11870 3460 11879 3482 11835 3482 11782

$$

SMITH/SUKUP

MORE INFORMATION FROM THE USGS ON DEBRIS FLOWS AND THEIR IMPACTS
CAN BE FOUND AT HTTP://LANDSLIDES.USGS.GOV/RESEARCH/WILDFIRE

2 follow-up statements

014 
WGUS76 KLOX 200035
FFSLOX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE OXNARD CA
535 PM PDT SUN JUL 19 2015

CAC037-200300-
/O.CON.KLOX.FF.W.0013.000000T0000Z-150720T0300Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
LOS ANGELES CA-
535 PM PDT SUN JUL 19 2015

...THE FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 800 PM PDT FOR
NORTHWESTERN LOS ANGELES COUNTY...

AT 532 PM PDT...DOPPLER RADAR AND AUTOMATED RAIN GAUGES INDICATED 
THAT HEAVY RAIN WAS FALLING OVER THE AREA. GAUGE DATA SHOWS THAT 
1.20 INCHES OF RAIN FELL IN ONE HOUR. FLASH FLOODING IS EXPECTED TO 
RESULT FROM THE HEAVY RAINFALL. 

EXCESSIVE RAINFALL OVER THE BURN SCAR WILL RESULT IN DEBRIS FLOW 
MOVING THROUGH THE POWERHOUSE BURN AREA NEAR CASTAIC LAKE. THE 
DEBRIS FLOW CAN CONSIST OF ROCK...MUD...VEGETATION AND OTHER LOOSE 
MATERIALS.

SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...ELIZABETH 
LAKE... CASTAIC LAKE...HIGHWAY 138 BETWEEN QUAIL LAKE AND THE 
POWERHOUSE BURN AREA.

LAT...LON 3442 11870 3460 11879 3482 11835 3482 11782

$$

SMITH

255 
WGUS56 KLOX 200259
FFWLOX
CAC037-200500-
/O.EXT.KLOX.FF.W.0013.000000T0000Z-150720T0500Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE OXNARD CA
759 PM PDT SUN JUL 19 2015

THE NATIONAL WEATHER SERVICE IN OXNARD HAS EXTENDED THE

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

* UNTIL 1000 PM PDT
    
* AT 753 PM PDT...DOPPLER RADAR AND AUTOMATED RAIN GAUGES CONTINUED 
  TO INDICATE SHOWERS AND THUNDERSTORMS PRODUCING MODERATE TO HEAVY 
  RAIN NEAR THE POWERHOUSE BURN AREA IN NORTHWESTERN LOS ANGELES 
  COUNTY. SOME RAIN GAUGES CONTINUED TO SHOW RAINFALL RATES OF A 
  HALF AN INCH TO THREE QUARTERS OF AN INCH PER HOUR. RUNOFF AND 
  ADDITIONAL RAINFALL WILL CONTINUE TO PRODUCE FLASH FLOODING IN 
  THIS AREA FOR SEVERAL MORE HOURS.

* SOME LOCATIONS THAT WILL EXPERIENCE FLOODING INCLUDE...ELIZABETH 
  LAKE...CASTAIC LAKE...HIGHWAY 138 BETWEEN QUAIL LAKE AND THE 
  POWERHOUSE BURN AREA.

LAT...LON 3442 11870 3460 11879 3482 11835 3482 11782

$$

SUKUP

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 19, 5:00 PM PDT	Special Weather Statement	LOX	Los Angeles	60 min
Jul 19, 5:15 PM PDT	Flash Flood Warning	LOX	Los Angeles	3 hr
Jul 19, 6:04 PM PDT	Flash Flood Warning	LOX	Los Angeles	3 hr
Jul 19, 6:22 PM PDT	Areal Flood Advisory	LOX	Los Angeles	5 hr
Jul 19, 7:33 PM PDT	Areal Flood Advisory	LOX	Ventura	3 hr
Jul 19, 8:11 PM PDT	Small Craft Advisory	LOX		13 hr
Jul 19, 8:52 PM PDT	Areal Flood Advisory	LOX	San Luis Obispo, Santa Barbara	3 hr
Jul 19, 11:44 PM PDT	Areal Flood Advisory	LOX	San Luis Obispo, Santa Barbara	61 min

Nearby

Flash Flood Warnings in California, 2015 Every 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.