Alert archive / Louisiana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 112, NWS New Orleans, LA

May 20, 2021Saint Charles Parish, Saint John the Baptist Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at May 20, 2021, 10:52 AM CDT for Saint Charles Parish, Saint John the Baptist Parish, Louisiana. It was in force for 19 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 20, 2021, 10:52 AM CDT (15:52 UTC)
Expired
May 20, 2021, 11:11 AM CDT
In force
19 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

Counties Saint Charles Parish, LA, Saint John the Baptist Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 3.9 hours before the alert went out and 87 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 12:00Z on 2021-05-20Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 622 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Slidell Radar S, LA at 12:00Z on 2021-05-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 152 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
622 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
599 m above ground
0-6 km bulk shear
19 kt
0-1 km storm-relative helicity
152 m²/s²
0-3 km storm-relative helicity
227 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

515 
WUUS54 KLIX 201552
SVRLIX
LAC089-095-201700-
/O.NEW.KLIX.SV.W.0112.210520T1552Z-210520T1700Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service New Orleans LA
1052 AM CDT Thu May 20 2021

The National Weather Service in New Orleans has issued a

* Severe Thunderstorm Warning for...
  Western St. John The Baptist Parish in southeastern Louisiana...
  Northwestern St. Charles Parish in southeastern Louisiana...

* Until noon CDT.

* At 1052 AM CDT, a severe thunderstorm was located near Killona, or
  near Reserve, moving north at 25 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect damage to roofs, siding, and trees.

* Locations impacted include...
  Reserve, Laplace, Garyville, Edgard, Wallace and Killona. 

This includes Interstate 10 in Louisiana between mile markers 198 and
204.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3022 9063 3022 9058 3019 9060 3017 9057
      3017 9051 2995 9052 2995 9060 3006 9066
TIME...MOT...LOC 1552Z 160DEG 20KT 2998 9054 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

CAB
2 follow-up statements
382 
WWUS54 KLIX 201557
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
1057 AM CDT Thu May 20 2021

LAC089-201606-
/O.CAN.KLIX.SV.W.0112.000000T0000Z-210520T1700Z/
St. Charles LA-
1057 AM CDT Thu May 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHWESTERN ST. CHARLES
PARISH IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3022 9063 3022 9058 3019 9060 3017 9057
      3017 9051 3002 9052 3002 9053 3000 9055
      2996 9055 2998 9058 3008 9066
TIME...MOT...LOC 1556Z 160DEG 20KT 3001 9055 

$$

LAC095-201700-
/O.CON.KLIX.SV.W.0112.000000T0000Z-210520T1700Z/
St. John The Baptist LA-
1057 AM CDT Thu May 20 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL NOON CDT FOR
WESTERN ST. JOHN THE BAPTIST PARISH...

At 1056 AM CDT, a severe thunderstorm was located over Edgard, or
near Reserve, moving north at 25 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...Expect damage to roofs, siding, and trees.

Locations impacted include...
Reserve, Laplace, Garyville, Edgard and Killona. 

This includes Interstate 10 in Louisiana between mile markers 197 and
204.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3022 9063 3022 9058 3019 9060 3017 9057
      3017 9051 3002 9052 3002 9053 3000 9055
      2996 9055 2998 9058 3008 9066
TIME...MOT...LOC 1556Z 160DEG 20KT 3001 9055 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...60MPH
 
$$

CAB
932 
WWUS54 KLIX 201611
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
1111 AM CDT Thu May 20 2021

LAC095-201621-
/O.CAN.KLIX.SV.W.0112.000000T0000Z-210520T1700Z/
St. John The Baptist LA-
1111 AM CDT Thu May 20 2021

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN ST. JOHN THE BAPTIST
PARISH IS CANCELLED...
                
The storm which prompted the warning has weakened below severe
limits, and no longer poses an immediate threat to life or property.
Therefore, the warning has been cancelled.

LAT...LON 3022 9063 3022 9058 3019 9060 3017 9057
      3017 9051 3002 9052 3002 9053 3000 9055
      2996 9055 2998 9058 3008 9066
TIME...MOT...LOC 1610Z 160DEG 20KT 3008 9058 

$$

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
May 19, 7:03 PM CDTSpecial Weather StatementLIXSaint Tammany42 min
May 19, 7:24 PM CDTSpecial Marine WarningLIX81 min
May 19, 8:00 PM CDTSevere Thunderstorm WarningLIXSaint Charles, Saint John the Baptist25 min
May 19, 8:30 PM CDTSpecial Marine WarningLIX30 min
May 19, 9:19 PM CDTAreal Flood AdvisoryLIXAscension, East Baton Rouge, Iberville, Livingston116 min
May 20, 3:42 AM CDTSpecial Weather StatementLIXAscension, Assumption, Iberville, Jefferson, Plaquemines, Saint Charles and 3 more63 min
May 20, 4:05 AM CDTSpecial Marine WarningLIX55 min
May 20, 4:18 AM CDTSpecial Marine WarningLIX57 min
May 20, 5:03 AM CDTSpecial Marine WarningLIX57 min
May 20, 5:33 AM CDTSpecial Marine WarningLIX57 min
May 20, 7:00 AM CDTSpecial Weather StatementLIXAssumption, Jefferson, Lafourche, Saint Charles, Saint James60 min
May 20, 7:39 AM CDTTornado WarningLIXJefferson8 min
May 20, 7:42 AM CDTSpecial Marine WarningLIX33 min
May 20, 8:27 AM CDTSpecial Marine WarningLIX63 min
May 20, 8:37 AM CDTAreal Flood AdvisoryLIXAscension, Assumption, East Baton Rouge, Iberville, Lafourche, Livingston and 3 more52 min
May 20, 8:58 AM CDTTornado WarningLIXEast Feliciana13 min
May 20, 9:29 AM CDTFlash Flood WarningLIXAscension, East Baton Rouge, Iberville, Livingston, West Baton Rouge9 hr
May 20, 9:45 AM CDTFlash Flood WarningLIXEast Baton Rouge, East Feliciana, Saint Helena, West Feliciana11 hr
May 20, 10:04 AM CDTFlash Flood WarningLIXAscension, Assumption, Iberville, Lafourche, Livingston, Saint James and 1 more13 hr
May 20, 11:22 AM CDTSpecial Marine WarningLIX38 min
May 20, 11:26 AM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, East Feliciana, Livingston, Saint Helena94 min
May 20, 2:16 PM CDTRiver Flood WarningLIXEast Baton Rouge, Livingston68 hr
May 20, 2:22 PM CDTRiver Flood WarningLIXAscension, Livingston4 days
May 20, 2:33 PM CDTSpecial Marine WarningLIX57 min
May 20, 2:40 PM CDTRiver Flood WarningLIXEast Baton Rouge61 hr
May 20, 3:29 PM CDTSpecial Marine WarningLIX61 min
May 20, 3:56 PM CDTGale WarningLIX19 hr
May 20, 3:56 PM CDTSmall Craft AdvisoryLIX60 hr
May 20, 3:56 PM CDTWind AdvisoryLIXOrleans, Saint Bernard, Saint John the Baptist, Saint Tammany27 hr
May 20, 4:30 PM CDTSpecial Marine WarningLIX90 min
May 20, 4:58 PM CDTSpecial Weather StatementLIXLafourche, Terrebonne47 min
May 20, 5:16 PM CDTAreal Flood AdvisoryLIXAssumption, Jefferson, Lafourche, Terrebonne3 hr
May 20, 6:42 PM CDTFlash Flood WarningLIXAscension, East Baton Rouge, Iberville, Livingston, Saint Helena, West Baton Rouge4 hr

Nearby

Severe Thunderstorm Warnings in Louisiana, 2021Every severe thunderstorm warning in 2021

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.