Alert archive / Louisiana / Flash Flood Warnings in 1989

Flash Flood Warning 13, NWS New Orleans, LA

November 7, 1989Orleans Parish, Plaquemines Parish, Saint Bernard Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at Nov 7, 1989, 12:20 PM CST for Orleans Parish, Plaquemines Parish, Saint Bernard Parish, Louisiana. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
Nov 7, 1989, 12:20 PM CST (18:20 UTC)
Expired
Nov 7, 1989, 4:15 PM CST
In force
4 hr
Issued by
NWS New Orleans, LA
Area
Whole counties

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

The radar

The WSR-88D network and its archive begin in 1991, so there is no radar volume for this alert.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 6.3 hours before the alert went out and 49 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 12:00Z on 1989-11-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 596 joules per kilogram.LCLLFCEL10008507005003002001001 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 12:00Z on 1989-11-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 130 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
596 J/kg
Mixed-layer CIN
-87 J/kg
Mixed-layer LCL
636 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
130 m²/s²
0-3 km storm-relative helicity
169 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 071829 RRA
FFWNEW
LAC051-071-075-087-072215-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1220 PM CST TUE NOV 7 1989
 
THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  415 PM CST
FOR PEOPLE IN THE FOLLOWING PARISHES...
 
IN SOUTHEAST LOUISIANA
          ...JEFFERSON...ORLEANS...NORTHERN PLAQUEMINES...ST.BERNARD
 
AT 1215 PM STRONG THUNDERSTORMS CONTINUED TO MOVE ACROSS THE GREATER
NEW ORLEANS METRO AREA. RAINFALL AMOUNTS SINCE 6AM HAVE RANGED BETWEEN
4 AND 7 INCHES. SPECIFIC TOTALS BETWEEN 6AM AND NOON INCLUDE: MOISANT
AIRPORT 6.90...LAKEFRONT AIRPORT 3.66...AUDABON PARK 4.20......BELLE
CHASE NAS 4.19...HARVEY 9.17. THE HEAVY RAIN HAS CAUSED WIDESPREAD
STREET FLOODING ACROSS THE METRO AREA. FLOODING OF HOUSES HAS BEEN
REPORTED ACROSS WEST BANK AREA OF JEFFERSON AND IN ST. BERNARD PARISH.
 
AT 1215 PM RADAR AND SATELITTE IMAGERY SHOWED RAIN AND THUNDERSTORMS
ACROSS THE NEW ORLEANS AREA. THESE THUNDERSTORMS WILL LIKELY CAUSE
ADDITIONAL HEAVY RAIN WHICH WILL COMPOUND THE FLOODING PROBLEMS AS PUMPSARE WORKING AT CAPACITY TO DRAIN ALREADY FLOODED AREAS. ALL UNECESSARY
TRAVEL IS DISCOURAGED ACROSS THE AREA AS MANY STREETS AND ROADWAYS
AREA FLOODED AND IMPASSABLE.
 
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 SJHOULD BE
ABANDONED QUICKLY.  MOVE TO HIGHER GROUND.

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

In the hours before

Special weather statement, Nov 7, 7:49 AM CST, 4 hours 31 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
750 AM CST TUE NOV 7 1989

...STRONG THUNDERSTORMS HEADED FOR THE METROPOLITAN NEW ORLEANS
   AREA...

AT 725 AM RADAR SHOWED A CLUSTER OF THUNDERSTORMS WITH HEAVY
RAIN JUST WEST OF THE NEW ORLEANS INTERNATIONAL AIRPORT SPREADING
NORTHEAST OUT OVER LAKE PONTCHARTRAIN. THESE THUNDERSTORMS ARE
CAPABLE OF PRODUCING PERIODS OF HEAVY RAINFALL...STRONG GUSTY WINDS
...AND DANGEROUS LIGHTNING. IN ADDITION PERIODS OF INTENSE DOWNPOURS
MAY REDUCE VISIBILITY TO NEAR ZERO. THESE THUNDERSTORMS HAVE BEEN
MOVING EAST NORTHEAST AT 15 MILES AN HOUR AND WILL MOVE ACROSS WESTERN
PORTIONS OF THE CITY AS WELL AS ACROSS LAKE PONTCHARTRAIN AND THE
CAUSEWAY BRIDGE. AS YOU ARE TRAVELING TO WORK THIS MORNING BE ALERT
FOR THESE THUNDERSTORMS AND THE POTENTIAL TRAFFIC HAZARD THEY MAY
CAUSE.

PATCHY LIGHT RAIN AND WIDELY SCATTERED SHOWERS AND THUNDERSTORMS
CONTINUED ACROSS NORTH PORTIONS OF SOUTHEAST LOUISIANA...EXTREME
SOUTH MISSISSIPPI AND THE ADJACENT COASTAL WATERS...AS WELL AS
EXTREME SOUTHWEST ALABAMA.

THUNDERSTORMS PRODUCING HEAVY RAINFALL WERE OCCURRING IN A BAND
STRETCHING FROM WEST OF SLIDELL EAST ONVER THE MISSISSIPPI SOUND TO
JUST SOUTH OF GULFPORT...AND WEST OF THE METRO NEW ORLEANS AREA.

MOVEMENT WAS EAST NORTHEAST AT 15 MILES AN HOUR.
Special weather statement, Nov 7, 8:50 AM CST, 3 hours 30 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
850 AM CST TUE NOV 7 1989

...STRONG THUNDERSTORMS OVER THE METROPOLITAN NEW ORLEANS
   AREA...

AT 825 AM RADAR SHOWED A CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN
NEAR NEW ORLEANS INTERNATIONAL AIRPORT EXTENDING EAST NEAR LAKE
BORGNE. HEAVY RAINS HAVE CAUSED SOME STREET FLOODING OVER LOW LYING
AREA OF NEW ORLEANS. PERSONS SHOULD BE ALERT FOR PERIODS OF INTENSE
DOWNPOURS...FREQUENT LIGHTNING...AND THE POSSIBILITY OF HAIL AS
THESE THUNDERSTORMS MOVE TO THE EAST NORTHEAST AT 15 MILES AN HOUR.

ELSEWHERE...SHOWERS AND THUNDERSTORMS CONTINUED OVER SOUTHEAST
LOUISIANA AND SOUTH MISSISSIPPI BETWEEN MC COMB AND MORGAN CITY
EXTENDING EAST BETWEEN LAUREL AND GULFPORT MISSISSIPPI.

MOVEMENT WAS TO THE EAST NORTHEAST AT 15 MILES AN HOUR.
Special weather statement, Nov 7, 9:46 AM CST, 2 hours 34 minutes before
SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
945 AM CST TUE NOV 7 1989

...RAIN CONTINUES OVER THE METROPOLITAN NEW ORLEANS AREA...

AT 925 AM RADAR SHOWED A CLUSTER OF THUNDERSTORMS WITH HEAVY RAIN
BETWEEN NEW ORLEANS AND LAKE BORGNE. ALTHOUGH THE THUNDERSTORMS
HAVE MOVE TO THE EAST OF THE CITY...RAIN SHOWERS ARE STILL OCCURRING
OVER METROPOLITAN NEW ORLEANS AND MAY PRODUCE SOME LOW LYING STREET
FLOODING AS THE STORMS MOVE TO THE EAST AT 10 MILES.

ELSEWHERE...SHOWERS AND THUNDERSTORMS CONTINUED OVER SOUTHEAST
LOUISIANA AND SOUTH MISSISSIPPI.

MOVEMENT WAS TO THE EAST AT 10 MILES AN HOUR.
Special weather statement, Nov 7, 9:52 AM CST, 2 hours 28 minutes before
URBAN FLOOD FLOOD STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
950 AM CST TUE NOV 7 1989

...HEAVY RAIN PELTS THE NEW ORLEANS METROPOLITAN AREA...

DURING THE PAST SEVERAL HOURS STRONG THUNDERSTORMS HAVE DEVELOPED
ALONG A LOW PRESSURE TROUGH LYING EAST WEST ACROSS SOUTHEAST LOUISIANA.
THE THUNDERSTORMS HAVE PRODUCED HEAVY RAINFALL WITH AMOUNTS 1 TO 3
INCHES LIKELY ACROSS THE AREA. WIDESPREAD STREET FLOODING HAS BEEN
REPORTED ACROSS THE METRO AREA ALONG WITH WATER ENTERING A FEW HOMES
IN LOW LYING AREAS OF WEST JEFFERSON PARISH.

AT LATE MORNING SATELLITE AND RADAR INDICATED THE HEAVIEST THUNDERSTORM
IN ST BERNARD MOVING INTO THE MISSISSIPPI SOUND. HOWEVER ADDITIONAL
THUNDERSTORMS ARE DEVELOPING JUST TO THE WEST OF METRO AREA. THESE
THUNDERSTORMS SHOULD MOVE EAST ACROSS THE AREA AND PRODUCE PERIODS OF
HEAVY RAIN INTO EARLY AFTERNOON.

RESIDENTS SHOULD EXERCISE CAUTION IN DRIVING IN FLOOD PRONE AREAS...
AND NOT ATTEMPT TO CROSS
FLOODED ROADWAYS.

The office that day

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

IssuedProductOfficeCountiesLasted
Nov 7, 10:18 AM CSTFlash Flood WarningLIXJefferson4 hr
Nov 7, 10:18 AM CSTFlash Flood WarningLIXSaint Bernard4 hr
Nov 7, 12:20 PM CSTFlash Flood WarningLIXJefferson4 hr
Nov 7, 1:36 PM CSTFlash Flood WarningLIXSaint Charles3 hr
Nov 7, 4:09 PM CSTFlash Flood WarningLIXJefferson, Plaquemines, Saint Bernard2 hr

Nearby

Flash Flood Warnings in Louisiana, 1989Every flash flood warning in 1989

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.