Alert archive / Louisiana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 106, NWS New Orleans, LA

May 11, 20216 parishes in Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at May 11, 2021, 11:41 PM CDT for 6 parishes in Louisiana. It was in force for 64 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 11, 2021, 11:41 PM CDT (04:41 UTC)
Expired
May 12, 2021, 12:45 AM CDT
In force
64 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Ascension Parish, LA, Assumption Parish, LA, Lafourche Parish, LA, Saint Charles 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, 4.7 hours before the alert went out and 101 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 2021-05-12Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 618 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 2021-05-12The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 135 square meters per square second.19395878Sfc1 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
618 J/kg
Mixed-layer CIN
-59 J/kg
Mixed-layer LCL
924 m above ground
0-6 km bulk shear
32 kt
0-1 km storm-relative helicity
135 m²/s²
0-3 km storm-relative helicity
212 m²/s²
Significant tornado parameter
0.3
Supercell composite
4.7

Open this sounding in Storm Lab

The text

As transmitted.

395 
WUUS54 KLIX 120441
SVRLIX
LAC005-007-057-089-093-095-120545-
/O.NEW.KLIX.SV.W.0106.210512T0441Z-210512T0545Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service New Orleans LA
1141 PM CDT Tue May 11 2021

The National Weather Service in New Orleans has issued a

* Severe Thunderstorm Warning for...
  Southwestern St. John The Baptist Parish in southeastern
  Louisiana...
  Southeastern Ascension Parish in southeastern Louisiana...
  St. James Parish in southeastern Louisiana...
  West central St. Charles Parish in southeastern Louisiana...
  Northwestern Lafourche Parish in southeastern Louisiana...
  Eastern Assumption Parish in southeastern Louisiana...

* Until 1245 AM CDT.

* At 1140 PM CDT, a severe thunderstorm was located near Chackbay, or
  8 miles north of Thibodaux, moving east at 20 mph.

  HAZARD...60 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  IMPACT...Hail damage to vehicles is expected. Expect wind damage 
           to roofs, siding, and trees.

* Locations impacted include...
  Thibodaux, Reserve, Gramercy, Lutcher, Wallace, Edgard, South
  Vacherie, Chackbay, Convent, North Vacherie, Garyville and Killona.

This includes Interstate 10 in Louisiana between mile markers 188 and
202.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3009 9095 3019 9072 3017 9069 3021 9068
      3022 9063 3022 9062 2990 9044 2979 9090
TIME...MOT...LOC 0440Z 265DEG 17KT 2991 9083 

HAIL...1.00IN
WIND...60MPH
 
$$

LN
2 follow-up statements
706 
WWUS54 KLIX 120507
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
1207 AM CDT Wed May 12 2021

LAC007-089-120517-
/O.CAN.KLIX.SV.W.0106.000000T0000Z-210512T0545Z/
St. Charles LA-Assumption LA-
1207 AM CDT Wed May 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL ST. CHARLES AND
EASTERN ASSUMPTION PARISHES IS CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 2988 9090 2988 9089 2993 9089 2994 9090
      3005 9090 3019 9072 3017 9069 3021 9068
      3022 9062 2997 9054 2993 9054 2979 9090
TIME...MOT...LOC 0507Z 265DEG 17KT 2992 9068 

$$

LAC005-057-093-095-120545-
/O.CON.KLIX.SV.W.0106.000000T0000Z-210512T0545Z/
St. John The Baptist LA-Ascension LA-St. James LA-Lafourche LA-
1207 AM CDT Wed May 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 AM CDT
FOR SOUTHWESTERN ST. JOHN THE BAPTIST...EAST CENTRAL ASCENSION...ST.
JAMES AND NORTHWESTERN LAFOURCHE PARISHES...

At 1207 AM CDT, a severe thunderstorm was located over South
Vacherie, or 11 miles northeast of Thibodaux, moving east at 20 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Thibodaux, Reserve, Gramercy, Lutcher, Wallace, South Vacherie,
Chackbay, Convent, North Vacherie, Garyville and Edgard.

This includes Interstate 10 in Louisiana between mile markers 190 and
200.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2988 9090 2988 9089 2993 9089 2994 9090
      3005 9090 3019 9072 3017 9069 3021 9068
      3022 9062 2997 9054 2993 9054 2979 9090
TIME...MOT...LOC 0507Z 265DEG 17KT 2992 9068 

HAIL...1.00IN
WIND...60MPH
 
$$

LN
909 
WWUS54 KLIX 120529
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
1229 AM CDT Wed May 12 2021

LAC005-120539-
/O.CAN.KLIX.SV.W.0106.000000T0000Z-210512T0545Z/
Ascension LA-
1229 AM CDT Wed May 12 2021

...THE SEVERE THUNDERSTORM WARNING FOR EAST CENTRAL ASCENSION 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 2988 9090 2988 9089 2993 9089 2994 9090
      2996 9082 3016 9060 2997 9054 2993 9054
      2979 9090
TIME...MOT...LOC 0529Z 271DEG 21KT 2994 9060 

$$

LAC057-093-095-120545-
/O.CON.KLIX.SV.W.0106.000000T0000Z-210512T0545Z/
St. John The Baptist LA-St. James LA-Lafourche LA-
1229 AM CDT Wed May 12 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1245 AM CDT
FOR SOUTHWESTERN ST. JOHN THE BAPTIST...SOUTHEASTERN ST. JAMES AND
NORTHWESTERN LAFOURCHE PARISHES...

At 1229 AM CDT, a severe thunderstorm was located near South
Vacherie, or 9 miles south of Reserve, moving east at 25 mph.

HAZARD...60 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect wind damage to 
         roofs, siding, and trees.

Locations impacted include...
Thibodaux, Reserve, Gramercy, Lutcher, Wallace, South Vacherie,
Chackbay, North Vacherie, Garyville and Edgard.

This includes Interstate 10 in Louisiana between mile markers 198 and
200.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 2988 9090 2988 9089 2993 9089 2994 9090
      2996 9082 3016 9060 2997 9054 2993 9054
      2979 9090
TIME...MOT...LOC 0529Z 271DEG 21KT 2994 9060 

HAIL...1.00IN
WIND...60MPH
 
$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 11, 8:49 PM CDTRiver Flood WarningLIXSaint Tammany14 hr
May 11, 9:24 PM CDTSpecial Weather StatementLIXAssumption51 min
May 11, 10:15 PM CDTSpecial Weather StatementLIXAscension30 min
May 11, 10:35 PM CDTSpecial Weather StatementLIXAscension, Assumption, Saint James40 min
May 11, 10:37 PM CDTSevere Thunderstorm WarningLIXAscension, Assumption, Iberville, Saint James30 min
May 11, 10:38 PM CDTFlash Flood WarningLIXAscension, Assumption, Iberville, Saint James3 hr
May 11, 11:05 PM CDTSevere Thunderstorm WarningLIXAscension, Assumption, Lafourche, Saint James, Saint John the Baptist40 min
May 12, 12:18 AM CDTSpecial Weather StatementLIXAssumption27 min
May 12, 12:31 AM CDTAreal Flood AdvisoryLIXAssumption, Jefferson, Lafourche, Saint Charles, Saint James, Saint John the Baptist2 hr
May 12, 12:33 AM CDTSpecial Weather StatementLIXSaint Charles42 min
May 12, 12:48 AM CDTSpecial Weather StatementLIXLafourche57 min
May 12, 1:12 AM CDTSpecial Weather StatementLIXSaint Charles33 min
May 12, 1:41 AM CDTSpecial Weather StatementLIXLafourche, Orleans, Saint Charles, Saint Tammany49 min
May 12, 1:46 AM CDTSpecial Marine WarningLIX44 min
May 12, 1:58 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles81 min
May 12, 1:58 AM CDTSevere Thunderstorm WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles32 min
May 12, 2:08 AM CDTTornado WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard12 min
May 12, 2:30 AM CDTSpecial Marine WarningLIX46 min
May 12, 2:47 AM CDTSpecial Marine WarningLIX43 min
May 12, 3:14 AM CDTSpecial Marine WarningLIX108 min
May 12, 4:25 AM CDTSpecial Marine WarningLIX65 min

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.