Alert archive / California / Flash Flood Warnings in 2003

Flash Flood Warning 14, NWS Los Angeles, CA

November 12, 2003Los Angeles County, California

NWS Los Angeles, CA issued this flash flood warning at Nov 12, 2003, 5:45 PM PST for Los Angeles County, California. It was in force for 105 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
Nov 12, 2003, 5:45 PM PST (01:45 UTC)
Expired
Nov 12, 2003, 7:30 PM PST
In force
105 min
Issued by
NWS Los Angeles, CA
Area
Counties, with a storm outline in the text

County Los Angeles County, CA

The radar

The Santa Ana Mts radar (KSOX), 41 km from the middle of the area, began a volume at 01:46 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.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

San Diego, CA (KNKX), launched 00:00Z, 1.8 hours before the alert went out and 160 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 00:00Z on 2003-11-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 352 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, San Diego, CA at 00:00Z on 2003-11-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -2 square meters per square second.1939587897117136Sfc1 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
352 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
659 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
-2 m²/s²
0-3 km storm-relative helicity
57 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.

000 
WGUS56 KLOX 130144
FFWLOX
CAC037-130330-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
545 PM PST WED NOV 12 2003

THE NATIONAL WEATHER SERVICE IN OXNARD HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  SOUTHERN AND EASTERN LOS ANGELES COUNTY IN SOUTHWEST
  CALIFORNIA...INCLUDING THE PADUA BURN AREA

* UNTIL 730 PM PST

* AT 525 PM PST...WEATHER SERVICE DOPPLER RADAR INDICATED VERY HEAVY
  RAIN ASSOCIATED WITH STRONG THUNDERSTORMS EXTENDING FROM NEAR THE 
  I-110 AND I-105 INTERSECTION IN SOUTH CENTRAL LOS ANGELES TO THE
  FOOTHILLS OF THE SAN GABRIEL VALLEY. RAINFALL RATES FROM AUTOMATED
  RAIN GAGES CONTINUE TO BE NEAR 2.5 INCHES PER HOUR BETWEEN COMPTON
  AND INGLEWOOD. RAINFALL RATES IN THE EASTERN SAN GABRIEL VALLEY
  WERE NEAR ONE INCH PER HOUR.

* LOCATIONS LIKELY TO EXPERIENCE FLASH FLOODING INCLUDE COMPTON...
  DIAMOND BAR...DOWNEY...EAST LOS ANGELES...EL MONTE...HAWTHORNE...
  HUNTINGTON PARK...INGLEWOOD...LA PUENTE...DOWNTOWN LOS ANGELES...
  LYNWOOD...MONTEBELLO...MONTEREY PARK...NORWALK...POMONA...ROWLAND
  HEIGHTS...SOUTH SAN JOSE HILLS...TORRANCE...WALNUT...WEST COVINA   
  AND WHITTIER.

EXCESSIVE RUNOFF FROM THIS STORM WILL CAUSE FLASH FLOODING OF SMALL
CREEKS AND STREAMS...URBAN AREAS...HIGHWAYS...STREETS AND UNDERPASSES
AS WELL AS OTHER DRAINAGE AREAS AND LOW LYING SPOTS. AREAS NEAR THE
PADUA BURN AREA CAN EXPECT THE DANGER OF MUDSLIDES AND DEBRIS FLOW.

DO NOT DRIVE YOUR VEHICLE INTO AREAS WHERE THE WATER COVERS THE
ROADWAY. THE WATER DEPTH MAY BE TOO GREAT TO ALLOW YOUR CAR TO CROSS
SAFELY. VEHICLES CAUGHT IN RISING WATER SHOULD BE ABANDONED QUICKLY.
MOVE TO HIGHER GROUND.

TO REPORT SEVERE WEATHER HAVE THE NEAREST LAW ENFORCEMENT AGENCY
RELAY YOUR REPORT TO THE NATIONAL WEATHER SERVICE FORECAST OFFICE IN
OXNARD.

LAT...LON 3422 11766 3396 11775 3389 11835 3422 11820

$$

MOYER

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

Hazardous weather outlook, Nov 12, 8:15 AM PST, 9 hours 30 minutes before
CAZ034>041-044>047-051>054-059-087-088-130200-

HAZARDOUS WEATHER OUTLOOK...CORRECTION
NATIONAL WEATHER SERVICE LOS ANGELES/OXNARD CA
815 AM PST WED NOV 12 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHWESTERN CALIFORNIA.

.DAY ONE...TODAY

NUMEROUS SHOWERS AND THUNDERSTORMS WILL OCCUR TODAY. THERE IS A
STRONG POTENTIAL FOR FLASH FLOODING IN THE BURN AREAS DUE TO THE
HIGH RAINFALL RATES ASSOCIATED WITH THUNDERSTORMS. A FLASH FLOOD
WATCH HAS BEEN ISSUED FOR THE BURN AREAS.

DANGEROUS LIGHTNING AND SMALL HAIL WILL BE POSSIBLE TODAY ANYWHERE
AND AT ANY TIME.

THE THUNDERSTORMS AND SHOWERS WILL DIMINISH OVERNIGHT.

THE SNOW LEVEL WILL LOWER TO BETWEEN 5000 AND 5500 FEET BY LATE THIS
AFTERNOON. SNOW WILL FALL THROUGH THE NIGHT. THE GREATEST
ACCUMULATIONS WILL BE OVER THE NORTHERN MOUNTAINS. 4 TO 8 INCHES OF
SNOW IS FORECAST OVER THE NORTHERN MOUNTAINS WHILE 2 TO 4 INCHES IS
FORECAST ELSEWHERE IN THE MOUNTAINS.

MOUNTAIN WINDS WILL BLOW FROM THE EAST TODAY FROM 20 TO 30 MPH WITH
GUSTS TO 40 MPH.

* FLOOD WATCH................SEE WGUS66 KLOX - FFALOX FOR DETAILS *

* WINTER WEATHER ADVISORY....SEE WWUS46 KLOX - WSWLOX FOR DETAILS *

.DAYS TWO THROUGH SEVEN... THURSDAY THROUGH TUESDAY

SNOW SHOWERS OVER THE MOUNTAINS WILL LINGER THROUGH THURSDAY
MORNING...OTHERWISE HAZARDOUS WEATHER IS NOT EXPECTED DURING THE
PERIOD.

* WINTER WEATHER ADVISORY....SEE WWUS46 KLOX - WSWLOX FOR DETAILS *

.SPOTTER INFORMATION STATEMENT...

WEATHER SPOTTERS ARE ENCOURAGED TO REPORT SIGNIFICANT WEATHER
CONDITIONS ACCORDING TO STANDARD OPERATING PROCEDURES.

RORKE/SWEET

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 12, 4:43 PM PSTFlash Flood WarningLOXLos Angeles62 min
Nov 12, 7:30 PM PSTFlash Flood WarningLOXLos Angeles2 hr
Nov 12, 9:30 PM PSTFlash Flood WarningLOXLos Angeles60 min

Nearby

Flash Flood Warnings in California, 2003Every flash flood warning in 2003

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.