Alert archive / Louisiana / Flash Flood Warnings in 1998

Flash Flood Warning 39, NWS New Orleans, LA

September 13, 1998Plaquemines Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Sep 13, 1998, 4:40 AM CDT for Plaquemines Parish, Louisiana. It was in force for 80 min. 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 13, 1998, 4:40 AM CDT (09:40 UTC)
Expired
Sep 13, 1998, 6:00 AM CDT
In force
80 min
Issued by
NWS New Orleans, LA
Area
Whole counties

County Plaquemines Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 9.7 hours before the alert went out and 79 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 1998-09-13Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 108 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 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 1998-09-13The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 114 square meters per square second.193958Sfc1 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
108 J/kg
Mixed-layer CIN
-22 J/kg
Mixed-layer LCL
796 m above ground
0-6 km bulk shear
13 kt
0-1 km storm-relative helicity
114 m²/s²
0-3 km storm-relative helicity
217 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KNEW 130940
FFWNEW
LAC075-131110-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
440 AM CDT SUN SEP 13 1998

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

* FLASH FLOOD WARNING FOR
   - NORTHWESTERN PLAQUEMINES PARISH IN SOUTHEASTERN LOUISIANA

* UNTIL 600 AM CDT

* AT 435 AM CDT...THE NATIONAL WEATHER SERVICE DOPPLER RADAR
  DETECTED A SOLID AREA OF HEAVY RAIN EXTENDING FROM THE CENTRAL
  JEFFERSON PARISH INTO THE NORTHWESTERN PALQUEMINES PARISH. THE
  STORM WAS MOVING SLOWLY NORTH AT 10 MPH.

THE FLASH FLOOD WARNING ISSUED EARLIER REMAINS IN EFFECT FOR THE
ENTIRE JEFFERSON PARISH AND THE WESTERN ORLEANS PARISH UNTIL 600 AM
CDT.

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.

IssuedProductOfficeCountiesLasted
Sep 13, 4:00 AM CDTFlash Flood WarningLIXJefferson, Orleans2 hr
Sep 13, 10:19 AM CDTFlash Flood WarningLIXLafourche3 hr

Nearby

Flash Flood Warnings in Louisiana, 1998Every 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.