Alert archive / Louisiana / Severe Thunderstorm Warnings in 1998

Severe Thunderstorm Warning 9, NWS New Orleans, LA

January 12, 1998Saint Tammany Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Jan 12, 1998, 8:46 AM CST for Saint Tammany Parish, Louisiana. It was in force for 59 min. 1 report came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Jan 12, 1998, 8:46 AM CST (14:46 UTC)
Expired
Jan 12, 1998, 9:45 AM CST
In force
59 min
Issued by
NWS New Orleans, LA
Area
Whole counties

County Saint Tammany Parish, LA

What was reported inside it

TimeReportWhereRemark
Jan 12, 9:12 AM CSTHail 0.75Slidell, LAPenny sized hail was reported in several locations between Mandeville and the Slidell area.

NCEI Storm Data entries that began inside the alert's area while it was in force. Before 2003 the local storm report archive is thin, so this is the record of what happened rather than what was phoned in.

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 2.8 hours before the alert went out and 30 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 1998-01-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 265 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 1998-01-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 411 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
265 J/kg
Mixed-layer CIN
-17 J/kg
Mixed-layer LCL
499 m above ground
0-6 km bulk shear
75 kt
0-1 km storm-relative helicity
411 m²/s²
0-3 km storm-relative helicity
492 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.0

Open this sounding in Storm Lab

The text

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

497 
WUUS1 KNEW 121447 RRA
SVRNEW
LAC103-121545-

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
846 AM CST MON JAN 12 1998

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS LA HAS ISSUED A
SEVERE THUNDERSTORM WARNING EFFECTIVE UNTIL 945 AM CST
FOR PEOPLE IN THE FOLLOWING LOCATION...

IN SOUTHEASTERN LOUISIANA

   ...SOUTHERN ST TAMMANY PARISH

AT 840 AM NATIONAL WEATHER SERVICE RADAR INDICATED A LINE OF
THUNDERSTORMS EXTENDING FROM COVINGTON TO MANDEVILLE AND INTO LAKE
PONTCHARTRAIN.

THE LINE WAS MOVING TO THE EAST AT 40 MPH. DAMAGING WIND GUST CAN
BE EXPECTED WITH THE PASSAGE OF THESE STORMS. COMMUNITIES IN THE
PATH OF THESE STORMS INCLUDE ABITA SPRINGS...LACOMBE AND SLIDELL.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER FROM THE WEATHER IN A
STRONG BUILDING.  DAMAGING WIND...LARGE HAIL...VERY HEAVY RAIN...
AND DEADLY LIGHTNING ARE ALL POSSIBLE IN SEVERE THUNDERSTORMS.
STAY INSIDE AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.

The office that day

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

IssuedProductOfficeCountiesLasted
Jan 12, 2:43 AM CSTSevere Thunderstorm WarningLIXPointe Coupee, West Feliciana62 min
Jan 12, 4:46 AM CSTSevere Thunderstorm WarningLIXPointe Coupee74 min
Jan 12, 6:33 AM CSTSevere Thunderstorm WarningLIXEast Baton Rouge, Livingston62 min
Jan 12, 7:12 AM CSTSevere Thunderstorm WarningLIXSaint Tammany, Tangipahoa63 min
Jan 12, 7:41 AM CSTSevere Thunderstorm WarningLIXTangipahoa119 min
Jan 12, 8:03 AM CSTFlash Flood WarningLIXSaint Tammany, Tangipahoa3 hr
Jan 12, 10:50 AM CSTTornado WarningLIXOrleans35 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 1998Every severe thunderstorm warning in 1998

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; verification from NCEI's Storm Data; the sounding from the Mesonet's radiosonde archive.