Alert archive / Louisiana / Flash Flood Warnings in 1990

Flash Flood Warning 10, NWS New Orleans, LA

May 31, 1990Tangipahoa Parish, Washington Parish, Louisiana

NWS New Orleans, LA issued this flash flood warning at May 31, 1990, 5:33 PM CDT for Tangipahoa Parish, Washington Parish, Louisiana. It was in force for 4 hr.

The area

The counties it named.

The facts

Issued
May 31, 1990, 5:33 PM CDT (22:33 UTC)
Expired
May 31, 1990, 9:30 PM CDT
In force
4 hr
Issued by
NWS New Orleans, LA
Area
Whole counties

Counties Tangipahoa Parish, LA, Washington 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, 10.6 hours before the alert went out and 74 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 1990-05-31Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1122 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 1990-05-31The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 78 square meters per square second.1939Sfc1 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
1122 J/kg
Mixed-layer CIN
-94 J/kg
Mixed-layer LCL
632 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
78 m²/s²
0-3 km storm-relative helicity
125 m²/s²
Significant tornado parameter
0.3
Supercell composite
2.4

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KNEW 312233
FFWNEW
LAC105-117-010230-
 
BULLETIN - EBS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
533 PM CDT THU MAY 31 1990
 
THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A
FLASH FLOOD WARNING EFFECTIVE UNTIL  930 PM CDT
FOR RESIDENTS IN THE FOLLOWING PARISHES
 
IN SOUTHEAST LOUISIANA
 
   ...TANGIPAHOA PARISH...WASHINGTON PARISH
 
SLIDELL WEATHER SERVICE RADAR AT 525 PM CDT INDICATED A BROAD
BAND OF STRONG THUNDERSTORMS WITH VERY HEAVY RAINFALL ACROSS
TANGIPAHOA AND WASHINGTON PARISHES. RAINFALL OBSERVERS AT MOUNT
HERMAN IN NORTHWEST WASHINGTON PARISH REPORTED 7.7 INCHES AS OF
5 PM AND KENTWOOOD OBSERVER REPORTED 4.4 INCHES. SOME FLOODING WAS
ALREADY REPORTED IN THE SOME OF STREETS AND HIGHWAYS WITH A FEW ROADS
CLOSED IN WASHINGTON PARISH. SIGHTSEERS ARE ADVISED TO STAY OUT
OF THE FLOODED AREAS. THUNDERSTORMS WITH HEAVY RAIN WILL LIKELY
CONTINUE FOR THE NEXT SEVERAL HOURS IN THESE TWO PARISHES.
 
 
A FLASH FLOOD WARNING MEANS THAT FLOODING IS OCCURRING OR IS
IMMINENT.  MOST FLASH FLOOD DEATHS OCCUR IN AUTOMOBILES.  DO NOT
ATTEMPT TO CROSS BRIDGES...DIPS...OR LOW SPOTS IF WATER COVERS
THE ROADWAY.  NEVER TRY TO CROSS A FLOWING STREAM...EVEN A SMALL
ONE...ON FOOT.  TO ESCAPE RISING WATER MOVE UP 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, May 31, 2:40 PM CDT, 2 hours 53 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-312035-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
235 PM CDT THU MAY 31 1990

A THUNDERSTORM WITH VERY HEAVY RAIN WAS LOCATED BETWEEN AMITE AND
KENTWOOD LOUISIANA. STRONG GUSTY WINDS...SMALL HAIL AND FREQUENT
LIGHTNING WILL ACCOMPANY THIS THUNDERSTORM AS IT MOVES SLOWLY
EAST. OTHER THUNDERSTORMS AND AREAS OF RAIN WERE OCCURRING ALONG
THE MISSISSIPPI STATE LINE. THE AREA WAS SHOWING VERY LITTLE MOVEMENT
AND PEOPLE SHOULD BE ON THE LOOKOUT FOR POSSIBLE FLOODING OF STREETS OR
ROADS.

THUNDERSTORMS WITH HEAVY RAIN AND LARGE AREAS OF LIGHT RAIN CONTINUED
OVER SOUTHERN MISSISSIPPI SOUTH OF JAKCSON TO NEAR PICAYUNE.
Special weather statement, May 31, 3:00 PM CDT, 2 hours 33 minutes before
LAZ006-008-009-312100-

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE BATON ROUGE LA
300 PM CDT THU MAY 31 1990

...A FLASH FLOOD WATCH IS IN EFFECT THIS AFTERNOON FOR AVOYELLES...
CATAHOULA AND CONCORDIA PARISHES OF EAST CENTRAL LOUISIANA...

RADAR SHOWED STRONG THUNDERSTORMS NORTH OF A LINE FROM HATTISBURG MS
SOUTHWEST TO NEAR BATON ROUGE THEN NORTHWEST TO ALEXANDRIA AND FORT
POLK.  THIS AREA IS MOVING SLOWLY SOUTHWARD.

AS THESE THUNDERSTORMS MOVE THROUGH THE AREA...THEY WILL PRODUCE STRONG
GUSTY WINDS...VERY HEAVY RAIN...DANGEROUS LIGHTNING STRIKES AND POSSIBLY
SOME SMALL HAIL.  THE HEAVY RAIN ALONG WITH THE SLOW MOVEMENT WILL CAUSE
FLOODING OF ROADWAYS..UNDERPASSES AND LOW LYING AREAS PRONE TO FLOODING.

DUE TO THE FACT THAT MANY RIVERS IN CENTRAL LOUISIANA ARE AT OR NEAR
FLOOD AT THE PRESENT TIME...RUNOFF FROM THESE HEAVY RAINS WILL BE SLOW.
PEOPLE ARE ADVISED NOT TO DRIVE THROUGH FLOODED AREAS.
.
THIS AREA OF THUNDERSTORMS WILL CONTINUE MOVING SOUTH OVER EAST CENTRAL
LOUISIANA FOR THE NEXT SEVERAL HOURS AND WILL LIKELY DECREAE LATE THIS
AFTERNOON OR EARLY TONIGHT. PEOPLE SHOULD KEEP ABREAST OF THE WEATHER
SITUATION AND BE PREPARED TO TAKE ACTION IF SEVERE WEATHER IS SIGHTED
OR A WARNING IS ISSUED.
Special weather statement, May 31, 3:38 PM CDT, 1 hour 55 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-312135-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
335 PM CDT THU MAY 31 1990

...HEAVY RAINS FALLING OVER SOUTHEAST LOUISIANA NORTH OF LAKE
PONTCHARTRAIN...

A THUNDERSTORM WITH VERY HEAVY RAIN CONTINUED OVER KENTWOOD LOUISIANA.
STRONG GUSTY WINDS...SMALL HAIL AND FREQUENT LIGHTNING WILL ACCOMPANY
THIS THUNDERSTORM AS IT MOVES VERY SLOWLY EAST. OTHER THUNDERSTORMS
WITH HEAVY RAIN WERE OCCURRING BETWEEN BATON ROUGE AND KENTWOOD TO
NEAR BOGALUSA. THE AREA WAS SHOWING VERY LITTLE MOVEMENT AND FOR THIS
REASON WATER WILL ACCUMULATE ON STREETS AND ROADS. PEOPLE SHOULD BE
ALERT TO THE POSSIBILITY OF FLOODING. KENTWOOD HAS REPORTED AROUND
TWO AND ONE-HALF INCHES OF RAIN SINCE NOON.

THUNDERSTORMS WITH HEAVY RAIN AND LARGE AREAS OF LIGHT RAIN CONTINUED
OVER SOUTHERN MISSISSIPPI SOUTH OF JAKCSON TO NEAR PICAYUNE AND NEAR
THE ALABAMA STATE LINE EAST OF HATTIESBURG.#
Special weather statement, May 31, 4:43 PM CDT, 50 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-312300-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
446 PM CDT THU MAY 31 1990

...THE SEVERE THUNDERSTORM WARNING ISSUED EARLIER FOR TANGIPAHOA PARISH
   IS NO LONGER IN EFFECT...
Special weather statement, May 31, 4:49 PM CDT, 44 minutes before
LAZ008>010-012>014-MSZ010>014-ALZ016-312300-

SPECIAL WEATHER STATEMENT AND RADAR SUMMARY
NATIONAL WEATHER SERVICE NEW ORLEANS LA
446 PM CDT THU MAY 31 1990

...THE SEVERE THUNDERSTORM WARNING ISSUED EARLIER FOR TANGIPAHOA PARISH
   IS NO LONGER IN EFFECT...

A BAND OF STRONG THUNDERSTORMS CONTINUED ACROSS SOUTHEAST LOUISIANA
FROM NEAR FRANKLINTON SOUTHWEST TO BETWEEN HAMMOND AND BATON ROUGE.

THESE THUNDERSTORMS WILL BE MOVING ACROSS TANGIPAHOA...WASHINGTON...AND
NORTHERN ST. TAMMANY PARISHES DURING THE NEXT HOUR AND WILL LIKELY
PRODUCE STRONG AND GUSTY WINDS...VERY HEAVY RAIN...AND POSSIBLY SOME
HAIL.

THESE THUNDERSTORMS ARE MOVING SLOWLY EAST AS THE AREA DRIFTS SOUTH.
DUE TO THE SLOW MOVEMENT OF THE STORMS SOME FLOODING OF STREETS AND
LOW LYING AREAS IS POSSIBLE IN THE VICINITY OF THE HEAVIER RAINS.

ELSEWHERE...SCATTERED THUNDERSTORMS AND LARGE PATCHES OF LIGHT RAIN
CONTINUED ACROSS MUCH OF SOUTHWEST MISSISSIPPI AND EXTENDED EAST TO
THE LAUREL AND HATTIESBURG AREAS.

The office that day

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

IssuedProductOfficeCountiesLasted
May 31, 3:58 PM CDTSevere Thunderstorm WarningLIXLivingston, Saint Helena47 min
May 31, 4:00 PM CDTSevere Thunderstorm WarningLIXTangipahoa45 min
May 31, 4:11 PM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, West Baton Rouge49 min
May 31, 4:11 PM CDTSevere Thunderstorm WarningLIXPointe Coupee49 min
May 31, 4:45 PM CDTSevere Thunderstorm WarningLIXAscension, East Baton Rouge, Livingston45 min
May 31, 4:45 PM CDTSevere Thunderstorm WarningLIXIberville, West Baton Rouge45 min
May 31, 5:30 PM CDTSevere Thunderstorm WarningLIXAscension, Livingston45 min
May 31, 5:30 PM CDTSevere Thunderstorm WarningLIXIberville45 min
May 31, 5:55 PM CDTTornado WarningLIXIberia, St. Mary65 min

Nearby

Flash Flood Warnings in Louisiana, 1990Every flash flood warning in 1990

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.