Alert archive / Mississippi / Flash Flood Warnings in 2012

Flash Flood Warning 76, NWS New Orleans, LA

August 30, 2012Walthall County, Mississippi; Washington Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Aug 30, 2012, 8:41 PM CDT for Walthall County, Mississippi; Washington Parish, Louisiana. It was in force for 3 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: Aug 30, 2012, 8:41 PM CDT (01:41 UTC)
Expired: Aug 30, 2012, 11:45 PM CDT
In force: 3 hr
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Flood severity: None

Counties Washington Parish, LA, Walthall County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 1.7 hours before the alert went out and 105 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: 1798 J/kg
Mixed-layer CIN: 0 J/kg
Mixed-layer LCL: 535 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 245 m²/s²
0-3 km storm-relative helicity: 250 m²/s²
Significant tornado parameter: 1.5
Supercell composite: 12.1

Open this sounding in Storm Lab

The text

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

928 
WGUS54 KLIX 310141
FFWLIX
LAC117-MSC147-310445-
/O.NEW.KLIX.FF.W.0076.120831T0141Z-120831T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
841 PM CDT THU AUG 30 2012

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  WESTERN WASHINGTON PARISH IN SOUTHEAST LOUISIANA...
  THIS INCLUDES THE CITY OF FRANKLINTON...
  WALTHALL COUNTY IN SOUTHERN MISSISSIPPI...

* UNTIL 1145 PM CDT

* AT 838 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED   
  A LINE OF VERY HEAVY RAINFALL ASSOCIATED WITH TROPICAL DEPRESSION  
  ISAAC MOVING ACROSS WALTHALL COUNTY AND NORTHWESTERN WASHINGTON    
  PARISH.  RAINFALL AMOUNTS OF 1 TO 3 INCHES PER HOUR ARE LIKELY AS  
  THIS BAND OF RAIN MOVES THROUGH.  FLASH FLOODING IS LIKELY         
  ESPECIALLY AS GROUNDS ARE SATURATED OR ALREADY FLOODED.

* LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO SALEM

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 3133 9008 3134 9005 3125 9004 3118 9002
      3117 9000 3113 9000 3113 8994 3108 8992
      3108 8984 3100 8983 3071 9025 3093 9035
      3100 9035 3100 9026 3135 9026 3135 9011

$$


DUNN

2 follow-up statements

482 
WGUS74 KLIX 310245
FFSLIX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
945 PM CDT THU AUG 30 2012

LAC117-MSC147-310445-
/O.CON.KLIX.FF.W.0076.000000T0000Z-120831T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WALTHALL MS-WASHINGTON LA-
945 PM CDT THU AUG 30 2012

...A FLASH FLOOD WARNING REMAINS IN EFFECT UNTIL 1145 PM CDT FOR
WALTHALL COUNTY...AND WESTERN WASHINGTON PARISH...

AT 943 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED VERY
HEAVY RAIN CONTINUING ACROSS THE WARNED AREA.  SHOWERS AND 
THUNDERSTORMS EXTEND FROM NORTHERN WALTHALL COUNTY THROUGH NORTHWEST 
WASHINGTON PARISH.  ADDITIONAL RAINFALL AMOUNTS OF 1 TO 2 INCHES 
WILL BE POSSIBLE THROUGH MIDNIGHT WITH THIS ACTIVITY.

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.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 AM CDT FRIDAY MORNING FOR
SOUTHERN MISSISSIPPI.

&&

LAT...LON 3133 9008 3134 9005 3125 9004 3118 9002
      3117 9000 3113 9000 3113 8994 3108 8992
      3108 8984 3100 8983 3071 9025 3093 9035
      3100 9035 3100 9026 3135 9026 3135 9011

$$


DUNN

989 
WGUS74 KLIX 310438
FFSLIX

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1138 PM CDT THU AUG 30 2012

LAC117-MSC147-310448-
/O.EXP.KLIX.FF.W.0076.000000T0000Z-120831T0445Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
WALTHALL MS-WASHINGTON LA-
1138 PM CDT THU AUG 30 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 1145 PM CDT FOR WALTHALL
COUNTY...AND WESTERN WASHINGTON PARISH...

THE HEAVY RAINFALL FROM EARLIER THIS EVENING HAS MOVED TO THE NORTH 
OF THE AREA.  ADDITIONAL SCATTERED SHOWERS WILL BE POSSIBLE DURING 
THE OVERNIGHT HOURS.

A TORNADO WATCH REMAINS IN EFFECT UNTIL 500 AM CDT FRIDAY MORNING FOR
SOUTHERN MISSISSIPPI.

LAT...LON 3133 9008 3134 9005 3125 9004 3118 9002
      3117 9000 3113 9000 3113 8994 3108 8992
      3108 8984 3100 8983 3071 9025 3093 9035
      3100 9035 3100 9026 3135 9026 3135 9011

$$


DUNN

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 8:44 PM CDT	Tornado Warning	LIX	Walthall	31 min
Aug 31, 2:39 PM CDT	Flash Flood Warning	LIX	Amite, Pike, Walthall	4 hr
Aug 30, 7:04 PM CDT	Flash Flood Warning	LIX	Ascension, Livingston, Tangipahoa	3 hr
Aug 31, 11:56 AM CDT	Flash Flood Warning	LIX	Ascension	3 hr

Nearby

Flash Flood Warnings in Mississippi, 2012 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; the sounding from the Mesonet's radiosonde archive.