Alert archive / Louisiana / Flash Flood Warnings in 2012

Flash Flood Warning 50, NWS New Orleans, LA

August 29, 20125 parishes in Louisiana

NWS New Orleans, LA issued this flash flood warning at Aug 29, 2012, 12:57 AM CDT for 5 parishes in Louisiana. It was in force for 6 hr. 5 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Aug 29, 2012, 12:57 AM CDT (05:57 UTC)
Expired
Aug 29, 2012, 6:45 AM CDT
In force
6 hr
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Flood severity
None

Counties Jefferson Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA

What was reported inside it

TimeReportWhereRemark
Aug 29, 3:35 AM CDTFLOOD3 Ene Belle Chasse, LAPLAQUEMINES PARISH EMERGENCY MANAGEMENT AND LOCAL LAW ENFORCEMENT REPORTED OVERTOPPING OF A PARISH BACK LEVEE FROM THE ST. BERNARD PARISH LINE TO WHITE DITCH. FLOOD WATERS ARE ENTERING THE EAST BANK OF PLAQUEMINES PARISH BETWEEN THOSE LOCATIONS AND EVACUATIONS
Aug 29, 3:35 AM CDTFLOOD3 Wnw Belle Chasse, LAPLAQUEMINES PARISH EMERGENCY MANAGEMENT AND LOCAL LAW ENFORCEMENT REPORTED OVERTOPPING OF A PARISH BACK LEVEE FROM THE ST. BERNARD PARISH LINE TO WHITE DITCH. FLOOD WATERS ARE ENTERING THE EAST BANK OF PLAQUEMINES PARISH BETWEEN THOSE LOCATIONS AND EVACUATIONS
Aug 29, 4:20 AM CDTFLOOD3 Ene Belle Chasse, LALOCAL LAW ENFORCEMENT REPORTED 5 FEET OF WATER IN THE WOODLAWN FIRE DEPARTMENT.
Aug 29, 4:20 AM CDTFLOOD3 Wnw Belle Chasse, LALOCAL LAW ENFORCEMENT REPORTED 5 FEET OF WATER IN THE WOODLAWN FIRE DEPARTMENT.
Aug 29, 5:27 AM CDTFLASH FLOODNew Orleans, LAWIDESPREAD AND SIGNIFICANT STREET FLOODING REPORTED IN DOWNTOWN AREA OF NEW ORLEANS.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 6.0 hours before the alert went out and 57 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, Slidell Radar S, LA at 00:00Z on 2012-08-29Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 275 joules per kilogram.LCLEL10008507005003002001001 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, Slidell Radar S, LA at 00:00Z on 2012-08-29The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 392 square meters per square second.19395878Sfc1 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
275 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
509 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
392 m²/s²
0-3 km storm-relative helicity
473 m²/s²
Significant tornado parameter
0.5
Supercell composite
8.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

866 
WGUS54 KLIX 290557
FFWLIX
LAC051-071-075-087-089-290845-
/O.NEW.KLIX.FF.W.0050.120829T0557Z-120829T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1257 AM CDT WED AUG 29 2012

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  JEFFERSON PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITIES OF...TIMBERLANE...METAIRIE...MARRERO...
  KENNER...HARVEY...AVONDALE...
  ORLEANS PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITIES OF...NEW ORLEANS...EAST NEW ORLEANS...
  NORTHWESTERN PLAQUEMINES PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITIES OF...PORT SULPHUR...BELLE CHASSE...
  WESTERN ST. BERNARD PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITY OF CHALMETTE...
  ST. CHARLES PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITY OF HAHNVILLE...

* UNTIL 345 AM CDT

* AT 1248 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS
  DETECTED FLASH FLOODING IS LIKELY FROM PERSISTENT TROPICAL
  RAINBANDS FROM HURRICANE ISAAC ACROSS THE SOUTHSHORE AREAS OF
  METROPOLITAN NEW ORLEANS...AND COASTAL AREAS TO THE EAST AND
  SOUTHEAST.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

EXCESSIVE RUNOFF FROM HEAVY RAINFALL WILL CAUSE FLOODING OF
CANALS...HIGHWAYS...UNDERPASSES...AND POOR DRAINAGE AREAS. DRAINAGE 
LIMITATIONS BECAUSE OF GATE CLOSURES AND VERY HIGH STORM TIDES WILL 
AUGMENT THE FLASH FLOOD POTENTIAL DURING PERSISTENT HEAVY RAIN. 

A FLASH FLOOD WARNING MEANS THAT FLOODING IS IMMINENT OR OCCURRING.
IF YOU ARE IN THE WARNING AREA MOVE TO HIGHER GROUND IMMEDIATELY. 
RESIDENTS LIVING IN AREAS SUBJECTED TO FLOODING SHOULD TAKE  
IMMEDIATE PRECAUTIONS TO PROTECT LIFE AND PROPERTY. DO NOT ATTEMPT 
TO CROSS SWIFTLY FLOWING WATERS OR WATERS OF UNKNOWN DEPTH BY FOOT 
OR BY AUTOMOBILE.

&&

LAT...LON 2950 9010 2967 9016 2980 9044 3002 9054
      3007 9038 3003 9011 3014 8972 3003 8971
      3004 8981 2995 8984 2997 8973 2989 8959
      2963 8948 2965 8963 2959 8971 2946 8951
      2939 8951 2938 8936 2931 8953

$$

22/TD
2 follow-up statements
424 
WGUS74 KLIX 290756
FFSLIX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
256 AM CDT WED AUG 29 2012

LAC051-071-075-087-089-290845-
/O.CON.KLIX.FF.W.0050.000000T0000Z-120829T0845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
ST. CHARLES LA-ORLEANS LA-JEFFERSON LA-PLAQUEMINES LA-ST. BERNARD LA-
256 AM CDT WED AUG 29 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 345 AM CDT FOR
WESTERN ST. BERNARD...NORTHWESTERN PLAQUEMINES...JEFFERSON...ORLEANS
AND ST. CHARLES PARISHES...

AT 250 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED TO 
DETECT A LARGE AREA OF HEAVY RAIN FROM TROPICAL RAINBANDS OVER THE 
WARNED AREA.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

ADDITIONAL RAINFALL AMOUNTS OF ONE TO TWO INCHES ARE POSSIBLE IN THE 
WARNED AREA THROUGH 4 AM...AND ADDITIONAL HEAVY RAINFALL IS EXPECTED 
THROUGH THE MORNING.

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 700 AM CDT WEDNESDAY MORNING
FOR SOUTHEAST LOUISIANA AND SOUTHERN MISSISSIPPI.

&&

LAT...LON 2950 9010 2967 9016 2980 9044 3002 9054
      3007 9038 3003 9011 3014 8972 3003 8971
      3004 8981 2995 8984 2997 8973 2989 8959
      2963 8948 2965 8963 2959 8971 2946 8951
      2939 8951 2938 8936 2931 8953

$$

22/TD
465 
WGUS54 KLIX 290837
FFWLIX
LAC051-071-075-087-089-291145-
/O.EXT.KLIX.FF.W.0050.000000T0000Z-120829T1145Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
337 AM CDT WED AUG 29 2012

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS EXTENDED THE

* FLASH FLOOD WARNING FOR...
  JEFFERSON PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITIES OF...TIMBERLANE...METAIRIE...MARRERO...
  KENNER...HARVEY...AVONDALE...
  ORLEANS PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITIES OF...NEW ORLEANS...EAST NEW ORLEANS...
  NORTHWESTERN PLAQUEMINES PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITIES OF...PORT SULPHUR...BELLE CHASSE...
  WESTERN ST. BERNARD PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITY OF CHALMETTE...
  ST. CHARLES PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITY OF HAHNVILLE...

* UNTIL 645 AM CDT

* AT 327 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS CONTINUED
  TO DETECTED VERY HEAVY RAINFALL THAT WILL LIKELY RESULT IN FLASH
  FLOODING ACROSS METROPOLITAN NEW ORLEANS AND ADJACENT COASTAL 
  AREAS. 
 
  IN ADDITION...EMERGENCY MANAGEMENT OFFICIALS IN PLAQUEMINES PARISH
  REPORTED OVERTOPPING OF A LEVEE ON THE EAST BANK FROM BRAITHWAITE
  TO WHITE DITCH. THIS WILL RESULT IN SIGNIFICANT DEEP FLOODING IN 
  THIS AREA.  

PRECAUTIONARY/PREPAREDNESS ACTIONS...

BE ESPECIALLY CAUTIOUS AT NIGHT WHEN IT IS HARDER TO RECOGNIZE THE 
DANGERS OF FLOODING. IF FLASH FLOODING IS OBSERVED ACT QUICKLY. MOVE 
UP TO HIGHER GROUND TO ESCAPE FLOOD WATERS. DO NOT STAY IN AREAS 
SUBJECT TO FLOODING WHEN WATER BEGINS RISING.

&&

LAT...LON 2950 9010 2967 9016 2980 9044 3002 9054
      3007 9038 3003 9011 3014 8972 3003 8971
      3004 8981 2995 8984 2997 8973 2989 8959
      2963 8948 2965 8963 2959 8971 2946 8951
      2939 8951 2938 8936 2931 8953

$$

22/TD

The office that day

Everything else NWS New Orleans, LA issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 28, 8:54 PM CDTRiver Flood WarningLIXTangipahoa7 days
Aug 28, 9:02 PM CDTRiver Flood WarningLIXSaint Tammany6 days
Aug 28, 9:08 PM CDTRiver Flood WarningLIXSaint Tammany4 days
Aug 28, 9:25 PM CDTRiver Flood WarningLIXWashington5 days
Aug 28, 9:31 PM CDTRiver Flood WarningLIXSaint Tammany8 days
Aug 28, 9:37 PM CDTRiver Flood WarningLIXSaint Tammany, Washington11 days
Aug 28, 9:43 PM CDTRiver Flood WarningLIXSaint Tammany13 days
Aug 29, 4:02 AM CDTFlash Flood Warning EmergencyLIXPlaquemines6 hr
Aug 29, 6:54 AM CDTFlash Flood WarningLIXJefferson, Orleans, Saint Bernard, Saint Charles3 hr
Aug 29, 9:15 AM CDTTornado WarningLIXWashington11 min
Aug 29, 10:11 AM CDTAreal Flood WarningLIXPlaquemines12 hr
Aug 29, 12:26 PM CDTSpecial Marine WarningLIX64 min
Aug 29, 12:34 PM CDTFlash Flood WarningLIXJefferson, Orleans, Saint Charles, Saint John the Baptist3 hr
Aug 29, 1:31 PM CDTSpecial Marine WarningLIX29 min
Aug 29, 1:51 PM CDTFlash Flood WarningLIXSaint Tammany, Washington3 hr
Aug 29, 1:53 PM CDTFlash Flood WarningLIXAscension, East Baton Rouge, Livingston, Tangipahoa3 hr
Aug 29, 4:44 PM CDTFlash Flood WarningLIXSaint Tammany, Washington3 hr
Aug 29, 6:01 PM CDTFlash Flood WarningLIXLafourche, Saint Charles, Saint John the Baptist3 hr

Nearby

Flash Flood Warnings in Louisiana, 2012Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.