Alert archive / Louisiana / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 13, NWS New Orleans, LA

January 9, 1999Saint Tammany Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Jan 9, 1999, 2:45 AM CST for Saint Tammany Parish, Louisiana. It was in force for 55 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 9, 1999, 2:45 AM CST (08:45 UTC)
Expired: Jan 9, 1999, 3:40 AM CST
In force: 55 min
Issued by: NWS New Orleans, LA
Area: Whole counties

County Saint Tammany Parish, LA

What was reported inside it

Time	Report	Where	Remark
Jan 9, 2:55 AM CST	Hail 0.75	Slidell, LA	A thunderstorm produced 0.75 inch diameter hail at the National Weather Service Forecast Office.

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 00:00Z, 8.8 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-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: 5 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 1095 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 88 m²/s²
0-3 km storm-relative helicity: 174 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 090845 RRA
SVRNEW
LAC103-090940-

BULLETIN - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE NEW ORLEANS LA
245 AM CST SAT JAN 9 1999

THE NATIONAL WEATHER SERVICE IN NEW ORLEANS LA HAS ISSUED A...

* SEVERE THUNDERSTORM WARNING FOR
   - ST TAMMANY PARISH IN SOUTHEASTERN LOUISIANA

* UNTIL 340 AM CST

* AT 240 AM CST... DOPPLER RADAR INDICATED A SEVERE THUNDERSTORM
OVER EASTERN LAKE PONTCHARTRAIN MOVING EAST NORTHEAST AT 30 MILES AN
HOUR. THIS THUNDERSTORM LIKELY CONTAINS MARBLE TO GOLF BALL SIZE
HAIL AND STRONG WINDS.

* THE SEVERE THUNDERSTORM WILL BE NEAR MANDEVILLE AND LACOMBE AT 245
AM... AND SLIDELL AND PEARL RIVER AT 250 AM...


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 DRIVE INTO AREAS WHERE| WATER COVERS THE ROAD.

The office that day

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

Issued	Product	Office	Counties	Lasted
Jan 9, 1:22 AM CST	Severe Thunderstorm Warning	LIX	Livingston	63 min
Jan 9, 1:44 AM CST	Severe Thunderstorm Warning	LIX	Tangipahoa	61 min
Jan 9, 2:16 AM CST	Severe Thunderstorm Warning	LIX	Saint John the Baptist	59 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 1999 Every severe thunderstorm warning in 1999

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.