Alert archive / Louisiana / Flash Flood Warnings in 2012

Flash Flood Warning 45, NWS New Orleans, LA

August 11, 2012Saint Tammany Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Aug 11, 2012, 5:40 AM CDT for Saint Tammany Parish, Louisiana. It was in force for 2 hr. 2 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 11, 2012, 5:40 AM CDT (10:40 UTC)
Expired: Aug 11, 2012, 7:45 AM CDT
In force: 2 hr
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Flood severity: None

County Saint Tammany Parish, LA

What was reported inside it

Time	Report	Where	Remark
Aug 11, 6:35 AM CDT	FLASH FLOOD	1 N Slidell, LA	MULTIPLE STREETS IMPASSIBLE IN SLIDELL. 5.02 INCHES OF RAIN OCCURRED IN 2 HOURS AT 16 MINS AT THE SLIDELL AIPORT.
Aug 11, 6:50 AM CDT	FLASH FLOOD	Slidell Airport, LA	FLASH FLOODING REPORTED IN NORTH SLIDELL. SOME STREETS IMPASSABLE.

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, 10.7 hours before the alert went out and 10 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: 911 J/kg
Mixed-layer CIN: -160 J/kg
Mixed-layer LCL: 1138 m above ground
0-6 km bulk shear: 16 kt
0-1 km storm-relative helicity: 0 m²/s²
0-3 km storm-relative helicity: 70 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.

223 
WGUS54 KLIX 111040
FFWLIX
LAC103-111245-
/O.NEW.KLIX.FF.W.0045.120811T1040Z-120811T1245Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
540 AM CDT SAT AUG 11 2012

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  SOUTHEASTERN ST. TAMMANY PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITY OF SLIDELL...

* UNTIL 745 AM CDT

* AT 534 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED   
  FLASH FLOODING POSSIBLE FROM A THUNDERSTORM NEAR SLIDELL...MOVING 
  EAST AT 5 MPH.

* OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO PEARL
  RIVER

PRECAUTIONARY/PREPAREDNESS ACTIONS...

2.75 INCHES OF RAIN HAS ALREADY OCCURRED IN JUST OVER AN HOUR AT THE 
SLIDELL AIRPORT AND AN ADDITIONAL 2 TO 3 INCHES OF RAINFALL ARE 
POSSIBLE IN THE WARNED AREA.

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 ALONG STREAMS AND CREEKS 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 3037 8967 3018 8964 3030 8993 3038 8989

$$

CAB

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 11, 2:55 AM CDT	Special Marine Warning	LIX		95 min
Aug 11, 7:14 AM CDT	Flash Flood Warning	LIX	Saint John the Baptist	2 hr
Aug 11, 7:55 AM CDT	Flash Flood Warning	LIX	Livingston	95 min
Aug 11, 8:01 AM CDT	Special Marine Warning	LIX		29 min
Aug 11, 8:27 AM CDT	Special Marine Warning	LIX		63 min
Aug 11, 8:36 AM CDT	Special Marine Warning	LIX		24 min
Aug 11, 10:00 AM CDT	Special Marine Warning	LIX		30 min
Aug 11, 10:37 AM CDT	Special Marine Warning	LIX		83 min
Aug 11, 11:26 AM CDT	Special Marine Warning	LIX		34 min
Aug 11, 12:04 PM CDT	Special Marine Warning	LIX		116 min

Nearby

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