Alert archive / Louisiana / Flash Flood Warnings in 1998

Flash Flood Warning 34, NWS New Orleans, LA

September 12, 1998Saint Tammany Parish, Louisiana; Hancock County, Mississippi

NWS New Orleans, LA issued this flash flood warning at Sep 12, 1998, 11:03 AM CDT for Saint Tammany Parish, Louisiana; Hancock County, Mississippi. 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 counties it named.

The facts

Issued: Sep 12, 1998, 11:03 AM CDT (16:03 UTC)
Expired: Sep 12, 1998, 1:40 PM CDT
In force: 3 hr
Issued by: NWS New Orleans, LA
Area: Whole counties

Counties Saint Tammany Parish, LA, Hancock County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 4.1 hours before the alert went out and 17 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: 5 J/kg
Mixed-layer CIN: -147 J/kg
Mixed-layer LCL: 884 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: 210 m²/s²
0-3 km storm-relative helicity: 424 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 
TTAA00 KNEW 121604
FFWNEW
LAC051-071-075-087-103-MSC045-121830-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1103 AM CDT SAT SEP 12 1998

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS LA HAS ISSUED A...

* FLASH FLOOD WARNING FOR
   - ST TAMMANY PARISH IN SOUTHEASTERN LOUISIANA
   - SOUTHERN JEFFERSON PARISH IN SOUTHEASTERN LOUISIANA
   - ORLEANS PARISH IN SOUTHEASTERN LOUISIANA
   - ST BERNARD PARISH IN SOUTHEASTERN LOUISIANA
   - PLAQUEMINES PARISH IN SOUTHEASTERN LOUISIANA
   - HANCOCK COUNTY IN SOUTHERN MISSISSIPPI

* UNTIL 140 PM CDT

* AT 1100 AM A LARGE AREA OF RAIN AND EMBEDDED THUNDERSTORMS
  EXTENDED FROM EAST ST TAMMANY PARISH ACROSS EAST ORLEANS AND ST
  BERNARD PARISH INTO PLAQUEMINE PARISH TO GRAND ISLE. THE AREA OF
  RAIN WAS MOVING SLOWLY NORTHEAST AROUND 10 TO 15 MPH. RAINFALL
  OF 2 TO 4 INCHES OF RAIN WILL LIKELY   OCCUR IN THE WARNED
  PARISHES AND COUNTIES FROM 11AM THROUGH 130PM.   DUE TO SATURATED
  GROUND CONDITIONS FLOODING OF LOW LYING AREAS AND ROADWAY WILL
  LIKELY OCCUR.

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.

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 12, 6:31 AM CDT	Flash Flood Warning	LIX	Ascension, Assumption, Saint James	3 hr
Sep 12, 6:31 AM CDT	Flash Flood Warning	LIX	Lafourche, Terrebonne	3 hr
Sep 12, 8:48 AM CDT	Flash Flood Warning	LIX	Orleans, Plaquemines, Saint Bernard	2 hr
Sep 12, 8:48 AM CDT	Flash Flood Warning	LIX	Jefferson, Saint Charles, Saint John the Baptist	2 hr
Sep 12, 11:03 AM CDT	Flash Flood Warning	LIX	Jefferson, Orleans, Plaquemines, Saint Bernard	3 hr
Sep 12, 1:28 PM CDT	Flash Flood Warning	LIX	Plaquemines	3 hr
Sep 12, 1:08 PM CDT	Severe Thunderstorm Warning	LIX	Hancock, Harrison	42 min
Sep 12, 1:28 PM CDT	Flash Flood Warning	LIX	Hancock, Harrison	3 hr

Nearby

Flash Flood Warnings in Louisiana, 1998 Flash Flood Warnings in Mississippi, 1998 Every flash flood warning in 1998

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.