Alert archive / Louisiana / Severe Thunderstorm Warnings in 2004

Severe Thunderstorm Warning 186, NWS New Orleans, LA

August 20, 2004Saint Tammany Parish, Tangipahoa Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Aug 20, 2004, 5:35 PM CDT for Saint Tammany Parish, Tangipahoa Parish, Louisiana. It was in force for 25 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: Aug 20, 2004, 5:35 PM CDT (22:35 UTC)
Expired: Aug 20, 2004, 6:00 PM CDT
In force: 25 min
Issued by: NWS New Orleans, LA
Area: Counties, with a storm outline in the text

Counties Saint Tammany Parish, LA, Tangipahoa Parish, LA

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 10.6 hours before the alert went out and 293 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: 2649 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 711 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: 120 m²/s²
0-3 km storm-relative helicity: 144 m²/s²
Significant tornado parameter: 1.0
Supercell composite: 6.4

Open this sounding in Storm Lab

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.

NWS New Orleans, LA wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 3:20 PM CDT, 2 hours 15 minutes earlier.

Area forecast discussion, Aug 20, 3:20 PM CDT, 2 hours 15 minutes before

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Hazardous weather outlook, Aug 20, 11:00 AM CDT, 6 hours 35 minutes before

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In the hours before

Special weather statement, Aug 20, 12:00 PM CDT, 5 hours 35 minutes before

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Special weather statement, Aug 20, 1:00 PM CDT, 4 hours 35 minutes before

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Special weather statement, Aug 20, 2:00 PM CDT, 3 hours 35 minutes before

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Special weather statement, Aug 20, 4:37 PM CDT, 58 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 20, 11:42 AM CDT	Special Marine Warning	LIX		2 hr

Nearby

Severe Thunderstorm Warnings in Louisiana, 2004 Every severe thunderstorm warning in 2004

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.