Alert archive / Louisiana / Tornado Warnings in 1990

Tornado Warning 21, NWS New Orleans, LA

December 18, 1990Washington Parish, Louisiana

NWS New Orleans, LA issued this tornado warning at Dec 18, 1990, 11:31 AM CST for Washington Parish, Louisiana. It was in force for 29 min.

The area

The counties it named.

The facts

Issued
Dec 18, 1990, 11:31 AM CST (17:31 UTC)
Expired
Dec 18, 1990, 12:00 PM CST
In force
29 min
Issued by
NWS New Orleans, LA
Area
Whole counties

County 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, 5.5 hours before the alert went out and 75 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 1990-12-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 97 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 1990-12-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 39 square meters per square second.1939587897Sfc1 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
97 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
593 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
39 m²/s²
0-3 km storm-relative helicity
118 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 181732 RRA
TORNEW
LAC117-181800-
 
BULLETIN - EBS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1131 AM CST TUE DEC 18 1990
 
THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A
TORNADO WARNING EFFECTIVE UNTIL NOON CST
FOR RESIDENTS IN THE FOLLOWING PARISHES
 
IN SOUTHEAST LOUISIANA
 
   ...WASHINGTON PARISH
 
AT 1110 AM THE STATE POLICE REPORTED A TORNADO TOUCHED DOWN 5 MILES
NORTH OF COVINGTON TAKING THE ROOF OFF OF A HOUSE. THE THUNDERSTORM
WHICH SPAWNED THIS TORNADO IS MOVING NORTHEAST 45 MILES AN HOUR.
 
 
IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A NEARBY REINFORCED
BUILDING.  AS A LAST RESORT...SEEK SHELTER IN A CULVERT...DITCH
OR LOW SPOT AND COVER YOUR HEAD WITH YOUR HANDS.

The office that day

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

IssuedProductOfficeCountiesLasted
Dec 18, 10:58 AM CSTTornado WarningLIXSaint Tammany, Tangipahoa62 min
Dec 18, 10:58 AM CSTTornado WarningLIXSaint Charles62 min

Nearby

Tornado Warnings in Louisiana, 1990Every tornado warning in 1990Tornadoes 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.