Alert archive / Louisiana / Severe Thunderstorm Warnings in 1990

Severe Thunderstorm Warning 64, NWS New Orleans, LA

August 30, 1990St. Mary Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Aug 30, 1990, 9:47 PM CDT for St. Mary Parish, Louisiana. It was in force for 58 min.

The area

The counties it named.

The facts

Issued: Aug 30, 1990, 9:47 PM CDT (02:47 UTC)
Expired: Aug 30, 1990, 10:45 PM CDT
In force: 58 min
Issued by: NWS New Orleans, LA
Area: Whole counties

County St. Mary 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

Lake Charles Mun, LA (KLCH), launched 00:00Z, 2.8 hours before the alert went out and 175 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 4254 J/kg
Mixed-layer CIN: -15 J/kg
Mixed-layer LCL: 1289 m above ground
0-6 km bulk shear: 25 kt
0-1 km storm-relative helicity: 86 m²/s²
0-3 km storm-relative helicity: 179 m²/s²
Significant tornado parameter: 1.8
Supercell composite: 14.9

Open this sounding in Storm Lab

The text

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

000 
TTAA00 KNEW 310247
SVRNEW
LAC101-310345-
 
BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
947 PM CDT THU AUG 30 1990
 
THE NATIONAL WEATHER SERVICE IN NEW ORLEANS HAS ISSUED A
SEVERE THUNDERSTORM AND SPECIAL MARINE WARNING
EFFECTIVE UNTIL 1045 PM CDT
FOR RESIDENTS IN THE FOLLOWING PARISHES
 
IN SOUTHEAST LOUISIANA
 
   ...ST.MARY PARISH
 
AND THE ADJACENT COASTAL WATERS OF SOUTHEAST LOUISIANA.
 
 
AT 945 PM RADAR INDICATED A SEVERE THUNDERSTORM JUST NORTH OF MORGAN
CITY AND PATTERSON. THE THUNDERSTORM WAS MOVING SOUTH AT 15 MILES AN
HOUR AND WILL BE AFFECTING ST MARY PARISH AND ADJACENT WATERS DURING
THE NEXT HOUR.
 
SEVERE THUNDERSTORMS PRODUCE DAMAGING WIND IN EXCESS OF 55
MPH...DESTRUCTIVE HAIL...DEADLY LIGHTNING...AND VERY HEAVY RAIN.
FOR YOUR PROTECTION MOVE TO AN INTERIOR ROOM ON THE LOWEST FLOOR
OF YOUR HOME OR BUSINESS.  HEAVY RAINS FLOOD ROADS QUICKLY SO
DON'T DREIVE INTO AREAS WHERE WATER COVERS THE ROAD.

What forecasters said that day

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

In the hours before

Local storm report, Aug 30, 8:18 PM CDT, 1 hour 29 minutes before

LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
815 PM CDT THU AUG 30 1990

SEVERE WEATHER REPORTS FOR AUG 30 OVER SE LOUISIANA

530PM CDT   ST. TAMMANY PARISH    HALF INCH HAIL REPORTED IN SLIDELL
                                  BY CITY POLICE AND AT NWSFO

525PM CDT   ST TAMMANY PARISH     TREES DOWNED BY WIND GUSTS IN
                                  MANDEVILLE...POLICE DEPT.

555PM CDT                         15 S MANDEVILLE WIND GUSTS TO 62 KTS
                                  ...71 MPH ON CAUSEWAY BRIDGE...NWS.

610PM CDT                         15 S MANDEVILLE WIND GUSTS TO 50 KTS
                                  63 MPH ON CAUSEWAY BRIDGE...NWS.

630-730PM  TANGIPAHOA PARISH      REPORTS OF TREES DOWN IN S PORTION
                                  OF PARISH..SHERIFFS OFFICE

645PM CDT  ORLEANS PARISH     LAKEFRONT ARPT...NEW...WIND GUST 45 KT
                              52 MPH

658PM CDT  ORLEANS PARISH6     N.O. INTERNATIONAL AIRPORT...MSY...WIND
                              GUST 45 KT...52 MPH.

700-730 PM  ST. CHARLES PARISH   POWER LINES DOWN IN SEVERAL
                                 COMMUNITIES...EOC.

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 30, 7:28 PM CDT	Severe Thunderstorm Warning	LIX	Livingston	62 min
Aug 30, 8:28 PM CDT	Tornado Warning	LIX	Iberia, Saint Martin	62 min
Aug 30, 9:19 PM CDT	Severe Thunderstorm Warning	LIX	Ascension, Iberville	56 min
Aug 30, 9:29 PM CDT	Severe Thunderstorm Warning	LIX	Assumption	61 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 1990 Every severe thunderstorm 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.