Alert archive / Louisiana / Severe Thunderstorm Warnings in 1991

Severe Thunderstorm Warning 33, NWS New Orleans, LA

April 9, 1991Saint Helena Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Apr 9, 1991, 7:35 PM CDT for Saint Helena Parish, Louisiana. It was in force for 55 min.

The area

The counties it named.

The facts

Issued
Apr 9, 1991, 7:35 PM CDT (00:35 UTC)
Expired
Apr 9, 1991, 8:30 PM CDT
In force
55 min
Issued by
NWS New Orleans, LA
Area
Whole counties

County Saint Helena Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 0.6 hours before the alert went out and 116 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 00:00Z on 1991-04-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 641 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 00:00Z on 1991-04-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 82 square meters per square second.193958Sfc1 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
641 J/kg
Mixed-layer CIN
-144 J/kg
Mixed-layer LCL
1423 m above ground
0-6 km bulk shear
34 kt
0-1 km storm-relative helicity
82 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.6

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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
Apr 9, 7:32 PM CDTSevere Thunderstorm WarningLIXJefferson, Orleans58 min
Apr 9, 7:32 PM CDTSevere Thunderstorm WarningLIXSaint Bernard58 min
Apr 9, 7:35 PM CDTSevere Thunderstorm WarningLIXSaint Landry55 min
Apr 9, 7:42 PM CDTSevere Thunderstorm WarningLIXSaint Bernard2 hr
Apr 9, 8:39 PM CDTSevere Thunderstorm WarningLIXSaint John the Baptist66 min
Apr 10, 12:46 AM CDTSevere Thunderstorm WarningLIXWashington59 min
Apr 10, 10:03 AM CDTSevere Thunderstorm WarningLIXPlaquemines57 min
Apr 10, 11:53 AM CDTSevere Thunderstorm WarningLIXSt. Mary37 min
Apr 10, 12:55 PM CDTSevere Thunderstorm WarningLIXJefferson, Orleans65 min
Apr 10, 6:01 PM CDTSevere Thunderstorm WarningLIXPointe Coupee, West Feliciana34 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 1991Every severe thunderstorm warning in 1991

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.