Alert archive / Louisiana / Severe Thunderstorm Warnings in 2020

Severe Thunderstorm Warning 29, NWS New Orleans, LA

April 18, 20204 parishes in Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Apr 18, 2020, 8:33 PM CDT for 4 parishes in Louisiana. It was in force for 57 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: Apr 18, 2020, 8:33 PM CDT (01:33 UTC)
Expired: Apr 18, 2020, 9:30 PM CDT
In force: 57 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Hail: 1.25 in
Wind: 50.0 mph

Counties Assumption Parish, LA, Lafourche Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 1.6 hours before the alert went out and 103 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: 514 J/kg
Mixed-layer CIN: -29 J/kg
Mixed-layer LCL: 570 m above ground
0-6 km bulk shear: 66 kt
0-1 km storm-relative helicity: 20 m²/s²
0-3 km storm-relative helicity: 92 m²/s²
Significant tornado parameter: 0.4
Supercell composite: 1.9

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 Apr 18, 3:14 PM CDT, 5 hours 19 minutes earlier.

Area forecast discussion, Apr 18, 3:14 PM CDT, 5 hours 19 minutes before

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In the hours before

Special weather statement, Apr 18, 7:10 PM CDT, 1 hour 23 minutes before

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Local storm report, Apr 18, 7:14 PM CDT, 1 hour 19 minutes before

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Local storm report, Apr 18, 7:15 PM CDT, 1 hour 18 minutes before

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      <p id="message1">
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Special weather statement, Apr 18, 7:46 PM CDT, 47 minutes before

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      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
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      <p id="message2">
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Special weather statement, Apr 18, 7:50 PM CDT, 43 minutes before

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      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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Local storm report, Apr 18, 8:30 PM CDT, 3 minutes before

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<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
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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
Apr 18, 7:10 PM CDT	Special Weather Statement	LIX	Tangipahoa, Washington	50 min
Apr 18, 7:46 PM CDT	Special Weather Statement	LIX	West Feliciana	59 min
Apr 18, 7:48 PM CDT	Severe Thunderstorm Warning	LIX	Pointe Coupee, West Feliciana	57 min
Apr 18, 7:50 PM CDT	Special Weather Statement	LIX	Saint Helena	55 min
Apr 18, 9:29 PM CDT	Special Weather Statement	LIX	Orleans	61 min
Apr 18, 9:32 PM CDT	Special Weather Statement	LIX	Saint Charles	13 min
Apr 18, 9:35 PM CDT	Severe Thunderstorm Warning	LIX	Jefferson, Orleans, Saint Bernard, Saint Charles	26 min
Apr 18, 9:56 PM CDT	Special Weather Statement	LIX	Assumption	49 min
Apr 18, 10:28 PM CDT	Special Weather Statement	LIX	Saint James	62 min
Apr 19, 4:13 AM CDT	Wind Advisory	LIX	Assumption, East Baton Rouge, East Feliciana, Iberville, Pointe Coupee, Saint Bernard and 7 more	19 hr
Apr 19, 4:30 AM CDT	Small Craft Advisory	LIX		7 hr
Apr 19, 10:51 AM CDT	Special Marine Warning	LIX		31 min
Apr 19, 11:08 AM CDT	Small Craft Advisory	LIX		19 hr
Apr 19, 11:08 AM CDT	Storm Warning	LIX		3 hr
Apr 19, 2:10 PM CDT	Special Marine Warning	LIX		95 min
Apr 19, 4:49 PM CDT	Special Weather Statement	LIX	Pointe Coupee, West Feliciana	56 min
Apr 19, 4:54 PM CDT	Severe Thunderstorm Warning	LIX	Pointe Coupee, West Feliciana	50 min
Apr 19, 5:35 PM CDT	Severe Thunderstorm Warning	LIX	East Feliciana, Saint Helena	70 min
Apr 19, 6:01 PM CDT	Tornado Warning	LIX	East Feliciana, Saint Helena, Tangipahoa	59 min
Apr 19, 6:39 PM CDT	Tornado Warning	LIX	Washington	38 min
Apr 19, 5:07 PM CDT	Special Weather Statement	LIX	Wilkinson	38 min
Apr 19, 5:11 PM CDT	Severe Thunderstorm Warning	LIX	Wilkinson	49 min
Apr 19, 5:41 PM CDT	Severe Thunderstorm Warning	LIX	Amite	49 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2020 Every severe thunderstorm warning in 2020

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.