Alert archive / Louisiana / Tornado Warnings in 1991

Tornado Warning 13, NWS New Orleans, LA

May 9, 1991Lafourche Parish, Terrebonne Parish, Louisiana

NWS New Orleans, LA issued this tornado warning at May 9, 1991, 9:01 AM CDT for Lafourche Parish, Terrebonne Parish, Louisiana. It was in force for 59 min.

The area

The counties it named.

The facts

Issued
May 9, 1991, 9:01 AM CDT (14:01 UTC)
Expired
May 9, 1991, 10:00 AM CDT
In force
59 min
Issued by
NWS New Orleans, LA
Area
Whole counties

Counties Lafourche Parish, LA, Terrebonne Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 2.0 hours before the alert went out and 128 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 1991-05-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 12 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°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 1991-05-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 118 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
12 J/kg
Mixed-layer CIN
-311 J/kg
Mixed-layer LCL
975 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
118 m²/s²
0-3 km storm-relative helicity
181 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 091403
TORNEW
LAC057-109-091500-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
901 AM CDT THU MAY 9 1991
 
THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL 1000 AM CDT
FOR RESIDENTS IN THE FOLLOWING PARISHES
 
IN SOUTHEAST LOUISIANA
 
   ...NORTHERN LAFOURCHE PARISH...NORTHERN TERREBONNE PARISH
 
AND THE ADJACENT COASTAL WATERS OF SOUTHEAST LOUISIANA.
 
 
A HELICOPTER PILOT FLYING IN THE HOUMA LOUISIANA AREA REPORTED THREE
FUNNEL CLOUDS POSSIBLY TOUCHING THE GROUND. THE STRONG THUNDERSTORM
PRODUCING THESE FUNNEL CLOUDS IS MOVING TOWARD THE NORTHEAST AT 35
MPH.
 
IF YOU ARE IN THE PATH OF A TORNADO...GET UNDER A! WORKBENCH OR PIECE
 OF STURDY FURNITURE.
IF NO BASEMENT IS AVAILABLE...SEEK SHELTER IN AN INTERIOR ROOM
SUCH AS A CLOSET ON THE LOWEST FLOOR.  USE BLANKETS...PILLOWS...
OR CUSHIONS TO COVER YOUR BODY.  AVOID WINDOWS.

What forecasters said that day

The local office's own words before this tornado 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, May 9, 5:25 AM CDT, 3 hours 36 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-091200-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
525 AM CDT THU MAY 9 1991

AT 525 AM CDT...A LARGE STRONG THUNDERSTORM WITH HEAVY RAIN WAS OVER VERMILION
BAY AND ANOTHER WAS ALONG THE COAST SOUTHWEST OF HOUMA. THESE STORMS WILL
PRODUCE STRONG GUSTY WINDS...HEAVY RAIN...DANGEROUS LIGHTNING AND POSSIBLY
SMALL HAIL. BOATERS ALONG THE COAST SHOULD SEEK SAFE SHELTER FROM THESE
STORMS.

ELSEWHERE WIDELY SCATTERED THUNDERSTORMS AND RAIN SHOWERS WERE FROM NEAR MORGAN
CITY EAST TO BETWEEN GRAND ISLE AND THIBODAUX AND OVER THE COASTAL WATERS FROM
VERMILION BAY TO TIMBALIER BAY.

SCATTERED PATCHES OF RAIN WERE ALONG THE COAST FROM PASCAGOULA MISSISSIPPI
EAST INTO NORTHWEST FLORIDA.

MOVEMENT WAS NORTHEAST AT 35 MILES AN HOUR.
Special weather statement, May 9, 6:17 AM CDT, 2 hours 44 minutes before
LAZ009-091210-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BATON ROUGE LA
610 AM CDT THU MAY 9 1991

...A LARGE THUNDERSTORM WAS MOVING TOWARD A PART OF EAST CENTRAL
LOUISIANA...

RADAR SHOWED A LARGE...STRONG THUNDERSTORM WITH VERY HEAVY RAIN
AND GUSTY WIND ABOUT 20 MILES SOUTHWEST OF PLAQUEMINE...IN IBERVILLE
PARISH...MOVING NORTHEAST TOWARD PLAQUEMINE ABOUT 30 MPH.

PEOPLE IN THE SOUTH HALF OF PLAQUEMINE PARISH SHOULD BE ALERT TO
THIS STORM FOR THE NEXT HOUR.  SINCE MOST BAYOUS AND SMALL RIVERS
ARE ALREADY FULL OR AT BANKFULL...THE ADDITIONAL HEAVY RAIN FROM THIS
STORM WILL CAUSE FLOODING OF ROADWAYS AND LOW LYING AREAS PRONE TO
FLOODING.  MOTORISTS ARE URGED TO PROCEED WITH EXTREME CAUTION THROUGH
FLOODED ROADWAYS.

AS ANOTHER ROUND OF RAIN...POSSIBLY HEAVY AT TIMES IS EXPECTED
THROUGHOUT EAST CENTRAL LOUISIANA TODAY...PEOPLE ON OR CLOSE TO
BAYOUS AND RIVERS SHOULD MONITOR THESE WEATHER CONDITIONS AND
BE READY TO TAKE &QUICK ACTION IF NEEDED.
Special weather statement, May 9, 6:31 AM CDT, 2 hours 30 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-091300-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
631 AM CDT THU MAY 9 1991

AT 631 AM CDT...A LARGE STRONG THUNDERSTORM WITH HEAVY RAIN WAS ABOUT
10 MILES NORTHWEST OF MORGAN CITY AND ANOTHER JUST SOUTHEAST OF THIBODAUX.
THESE STORMS WILL PRODUCE STRONG GUSTY WINDS...HEAVY RAIN...DANGEROUS LIGHTNING
AND POSSIBLY SMALL HAIL. SOME STREET FLOODING WILL LIKELY OCCUR WITH THESE
STORMS. THESE STORMS WERE MOVING NORTHEAST AT 35 MILES AN HOUR.

ELSEWHERE SCATTERED RAIN SHOWERS AND THUNDERSTORMS EXTENDED INLAND FROM THE
COASTAL WATERS BETWEEN VERMILION BAY AND GRAND ISLE TO JUST SOUTH OF BATON
ROUGE AND TO JUST WEST OF NEHW ORLEANS.

WIDELY SCATTERED RAIN SHOWERS WERE IN SOUTHWEST ALABAMA.
Special weather statement, May 9, 6:43 AM CDT, 2 hours 18 minutes before
LAZ009-091240-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BATON ROUGE LA
640 AM CDT THU MAY 9 1991

...THUNDERSTORMS WITH VERY HEAVY RAIN WERE APPROACHING PARTS OF
EAST CENTRAL LOUISIANA...

RADAR SHOWED THE STRONG THUNDERSTORM WITH VERY HEAVY RAIN AND STRONG
AND GUSTY WIND THAT WAS MOVING TOWARD PLAQUEMINE HAD TURNED MORE
EASTWARD AND WAS LOCATED JUST SOUTHWEST OF DONALDSONVILLE.  THIS
STORM WILL MOVE THROUGH THE REMAINDER OF EXTREME SOUTHEAST IBERVILLE
AND ACROSS ASCENSION AND THE SOUTHERN PART OF LIVINGSTON PARISHES
FOR THE NEXT HOUR.

ANOTHER STRONG THUNDERSTORM WAS LOCATED NEAR GRAMERCY AND RESERVE
MOVING NORTHEAST ABOUT 30 MPH TOWARD SOUTHERN LIVINGSTON PARISH.

PEOPLE IN THESE AREAS CAN EXPECT THE VERY HEAVY RAIN TO RUNOFF QUICKLY
SINCE THE GROUND IS ALREADY WELL SATURATED AND MANY SMALL BAYOUS AND
STREAMS ARE SWOLLEN OR AT BANKFULL...FLOODING STREETS AND ROADWAYS
AND LOW LYING AREAS PRONE TO FLOODING.

AS ANOTHER? ROUND OF RAIN...POSSIBLY HEAVY AT TIMES...IS EXPECTED
THROUGHOUT EAST CENTRAL LOUISIANA TODAY...PEOPLE ON OR CLOSE TO
BAYOUS AND RIVERS SHOULD MONITOR THESE WEATHER CONDITIONS AND
BE READY TO TAKE QUICK ACTION IF NEEDED.
Special weather statement, May 9, 8:48 AM CDT, 13 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-091500-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
840 AM CDT THU MAY 9 1991

AT 830 AM CDT...A LARGE AREA OF SHOWERS AND THUNDESTORMS CONTINUED OVER
SOUTHEAST LOUISIANA FROM JUST NORTH OF BOGALUSA EXTENDING SOUTHWEST TO
BETWEEN BATON ROUGE AND POINTE A LA HACHE AND CONTINUING SOUTHWEST IN
COASTAL WATERS BETWEEN VERMILION AND TERREBONNE BAY. THE STRONGEST
THUNDERSTORMS WERE LOCATED OVER THE NEW ORLEANS AREA AND NEAR HOUMA.

THESE STORMS WILL PRODUCE STRONG GUSTY WINDS...HEAVY RAIN...DANGEROUS
LIGHTNING AND POSSIBLY SMALL HAIL. SOME STREET FLOODING WILL LIKELY
OCCUR WITH THESE THUNDERSTORMS. THE THUNDERSTORMS WERE MOVING NORTHEAST
AT 35 MILES AN HOUR.
Special weather statement, May 9, 8:50 AM CDT, 11 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-091500-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
840 AM CDT THU MAY 9 1991

AT 830 AM CDT...A LARGE AREA OF THUNDERSTORMS WITH HEAVY RAIN CONTINUED
OVER SOUTHEAST LOUISIANA FROM JUST NORTH OF BOGALUSA EXTENDING SOUTHWEST
TO BETWEEN BATON ROUGE AND POINTE A LA HACHE AND CONTINUING SOUTHWEST IN
COASTAL WATERS BETWEEN VERMILION AND TERREBONNE BAY. THE STRONGEST
THUNDERSTORMS WERE LOCATED OVER THE NEW ORLEANS AREA AND NEAR HOUMA.

THESE STORMS WILL PRODUCE STRONG GUSTY WINDS...HEAVY RAIN...DANGEROUS
LIGHTNING AND POSSIBLY SMALL HAIL. SOME STREET FLOODING WILL LIKELY
OCCUR WITH THESE THUNDERSTORMS. THE THUNDERSTOR
MS WERE MOVING NORTHEAST
AT 35 MILES AN HOUR.

The office that day

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

IssuedProductOfficeCountiesLasted
May 8, 9:17 PM CDTSevere Thunderstorm WarningLIXSaint Landry58 min
May 9, 11:12 AM CDTTornado WarningLIXLafourche48 min
May 9, 11:37 AM CDTTornado WarningLIXJefferson, Saint Charles53 min
May 9, 12:18 PM CDTSevere Thunderstorm WarningLIXSaint Tammany57 min

Nearby

Tornado Warnings in Louisiana, 1991Every tornado warning in 1991Tornadoes in 1991

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.