Alert archive / Louisiana / Severe Thunderstorm Warnings in 1999

Severe Thunderstorm Warning 254, NWS New Orleans, LA

September 7, 1999Saint John the Baptist Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Sep 7, 1999, 3:29 PM CDT for Saint John the Baptist Parish, Louisiana. It was in force for 51 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 7, 1999, 3:29 PM CDT (20:29 UTC)
Expired
Sep 7, 1999, 4:20 PM CDT
In force
51 min
Issued by
NWS New Orleans, LA
Area
Whole counties

County Saint John the Baptist Parish, LA

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 8.5 hours before the alert went out and 262 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, Lake Charles Mun, LA at 12:00Z on 1999-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1440 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, Lake Charles Mun, LA at 12:00Z on 1999-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -20 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
1440 J/kg
Mixed-layer CIN
-40 J/kg
Mixed-layer LCL
915 m above ground
0-6 km bulk shear
12 kt
0-1 km storm-relative helicity
-20 m²/s²
0-3 km storm-relative helicity
-3 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 7, 3:11 PM CDTSevere Thunderstorm WarningLIXAscension, Saint James49 min
Sep 7, 3:56 PM CDTSevere Thunderstorm WarningLIXIberville, Pointe Coupee, West Baton Rouge49 min
Sep 7, 4:34 PM CDTSevere Thunderstorm WarningLIXTangipahoa31 min
Sep 7, 5:40 PM CDTSevere Thunderstorm WarningLIXHancock, Pearl River25 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 1999Every 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; the sounding from the Mesonet's radiosonde archive.