Alert archive / Louisiana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 99, NWS New Orleans, LA

May 10, 20218 parishes in Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at May 10, 2021, 9:16 AM CDT for 8 parishes in Louisiana. It was in force for 44 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 10, 2021, 9:16 AM CDT (14:16 UTC)
Expired
May 10, 2021, 10:00 AM CDT
In force
44 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

Counties Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Tangipahoa Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 2.3 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 12:00Z on 2021-05-10Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 161 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 12:00Z on 2021-05-10The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 51 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
161 J/kg
Mixed-layer CIN
-137 J/kg
Mixed-layer LCL
943 m above ground
0-6 km bulk shear
36 kt
0-1 km storm-relative helicity
51 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted.

396 
WUUS54 KLIX 101416
SVRLIX
LAC005-007-033-047-063-093-095-105-101500-
/O.NEW.KLIX.SV.W.0099.210510T1416Z-210510T1500Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service New Orleans LA
916 AM CDT Mon May 10 2021

The National Weather Service in New Orleans has issued a

* Severe Thunderstorm Warning for...
  Western St. John The Baptist Parish in southeastern Louisiana...
  Ascension Parish in southeastern Louisiana...
  St. James Parish in southeastern Louisiana...
  Southern Livingston Parish in southeastern Louisiana...
  Southeastern Iberville Parish in southeastern Louisiana...
  Southwestern Tangipahoa Parish in southeastern Louisiana...
  South central East Baton Rouge Parish in southeastern Louisiana...
  Northeastern Assumption Parish in southeastern Louisiana...

* Until 1000 AM CDT.

* At 915 AM CDT, severe thunderstorms were located along a line
  extending from near Port Vincent to 6 miles northeast of Pierre
  Part, moving east at 45 mph.

  HAZARD...60 mph wind gusts.

  SOURCE...Radar indicated.

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

* Locations impacted include...
  Baton Rouge, Denham Springs, Gonzales, Donaldsonville, Reserve, Oak
  Hills Place, Laplace, St. Gabriel, Gramercy, Lutcher, White Castle,
  Sorrento, French Settlement, Port Vincent, Westminster, Geismar,
  Garyville, Shenandoah, Whitehall and Old Jefferson.

This includes the following Interstates...
 Interstate 10 in Louisiana between mile markers 162 and 204.
 Interstate 12 between mile markers 3 and 12.
 Interstate 55 in Louisiana between mile markers 15 and 22.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Large hail and damaging winds and continuous cloud to ground
lightning is occurring with these storms. Move indoors immediately.
Lightning is one of nature's leading killers. Remember, if you can
hear thunder, you are close enough to be struck by lightning.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3033 9117 3033 9115 3034 9115 3048 9103
      3038 9034 3027 9041 3032 9042 3034 9047
      3030 9056 3026 9059 3022 9057 3019 9060
      3017 9057 3018 9047 2989 9065 3009 9138
TIME...MOT...LOC 1415Z 275DEG 37KT 3033 9091 3004 9116 

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

MSW
2 follow-up statements
677 
WWUS54 KLIX 101445
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
945 AM CDT Mon May 10 2021

LAC033-047-101455-
/O.CAN.KLIX.SV.W.0099.000000T0000Z-210510T1500Z/
Iberville LA-East Baton Rouge LA-
945 AM CDT Mon May 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHEASTERN IBERVILLE AND
SOUTH CENTRAL EAST BATON ROUGE PARISHES IS CANCELLED...

The storms which prompted the warning have moved out of the warned 
area. Therefore, the warning has been cancelled.

LAT...LON 3007 9110 3033 9101 3034 9090 3038 9095
      3040 9094 3044 9078 3038 9034 3029 9040
      3032 9042 3034 9049 3030 9056 3026 9059
      3022 9057 3019 9060 3017 9057 3018 9047
      2989 9065 3004 9118
TIME...MOT...LOC 1445Z 275DEG 37KT 3030 9057 3001 9083 

$$

LAC005-007-063-093-095-105-101500-
/O.CON.KLIX.SV.W.0099.000000T0000Z-210510T1500Z/
St. John The Baptist LA-Ascension LA-St. James LA-Livingston LA-
Tangipahoa LA-Assumption LA-
945 AM CDT Mon May 10 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 1000 AM CDT
FOR WESTERN ST. JOHN THE BAPTIST...ASCENSION...ST. JAMES...SOUTHERN
LIVINGSTON...SOUTH CENTRAL TANGIPAHOA AND NORTHEASTERN ASSUMPTION
PARISHES...

At 945 AM CDT, severe thunderstorms were located along a line
extending from 7 miles east of Whitehall to Convent, moving east at
45 mph.

HAZARD...60 mph wind gusts.

SOURCE...Radar indicated.

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

Locations impacted include...
Gonzales, Donaldsonville, Reserve, Laplace, Gramercy, Lutcher,
Sorrento, French Settlement, Port Vincent, South Vacherie, Geismar,
Convent, North Vacherie, Garyville, Prairieville, Wallace, Whitehall,
Belle Rose, Edgard and Killian.

This includes the following Interstates...
 Interstate 10 in Louisiana between mile markers 169 and 204.
 Interstate 55 in Louisiana between mile markers 16 and 22.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

Continuous cloud to ground lightning is occurring with these storms.
Move indoors immediately. Lightning is one of nature's leading
killers. Remember, if you can hear thunder, you are close enough to
be struck by lightning.

Torrential rainfall is occurring with these storms, and may lead to
flash flooding. Do not drive your vehicle through flooded roadways.

&&

LAT...LON 3007 9110 3033 9101 3034 9090 3038 9095
      3040 9094 3044 9078 3038 9034 3029 9040
      3032 9042 3034 9049 3030 9056 3026 9059
      3022 9057 3019 9060 3017 9057 3018 9047
      2989 9065 3004 9118
TIME...MOT...LOC 1445Z 275DEG 37KT 3030 9057 3001 9083 

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

MEFFER
582 
WWUS54 KLIX 101459
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
959 AM CDT Mon May 10 2021

LAC005-007-063-093-095-105-101509-
/O.EXP.KLIX.SV.W.0099.000000T0000Z-210510T1500Z/
St. John The Baptist LA-Ascension LA-St. James LA-Livingston LA-
Tangipahoa LA-Assumption LA-
959 AM CDT Mon May 10 2021

...THE SEVERE THUNDERSTORM WARNING FOR WESTERN ST. JOHN THE
BAPTIST...ASCENSION...ST. JAMES...SOUTHERN LIVINGSTON...SOUTH CENTRAL
TANGIPAHOA AND NORTHEASTERN ASSUMPTION PARISHES WILL EXPIRE AT 1000
AM CDT...
            
The storms which prompted the warning have weakened below severe
limits, and no longer pose an immediate threat to life or property.
Therefore, the warning will be allowed to expire.

LAT...LON 3007 9110 3033 9101 3034 9090 3038 9095
      3040 9094 3044 9078 3038 9034 3029 9040
      3032 9042 3034 9049 3030 9056 3026 9059
      3022 9057 3019 9060 3017 9057 3018 9047
      2989 9065 3004 9118
TIME...MOT...LOC 1459Z 275DEG 37KT 3029 9042 3000 9068 

$$

MEFFER

The office that day

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

IssuedProductOfficeCountiesLasted
May 9, 8:48 PM CDTFlash Flood WatchLIXAssumption, East Baton Rouge, East Feliciana, Iberville, Orleans, Pointe Coupee and 9 more15 hr
May 10, 1:00 AM CDTSpecial Weather StatementLIXAscension, Livingston60 min
May 10, 1:29 AM CDTAreal Flood AdvisoryLIXAscension, Assumption, Iberville, Saint James70 min
May 10, 1:49 AM CDTSpecial Weather StatementLIXAssumption, Saint James, Saint John the Baptist56 min
May 10, 1:54 AM CDTSevere Thunderstorm WarningLIXAscension, Assumption, Saint James51 min
May 10, 2:01 AM CDTSpecial Marine WarningLIX59 min
May 10, 2:43 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles2 hr
May 10, 2:52 AM CDTSpecial Marine WarningLIX53 min
May 10, 2:57 AM CDTFlash Flood WarningLIXJefferson, Orleans, Saint Charles9 hr
May 10, 3:25 AM CDTSpecial Weather StatementLIXOrleans35 min
May 10, 3:37 AM CDTSpecial Marine WarningLIX113 min
May 10, 3:41 AM CDTTornado WarningLIXOrleans, Plaquemines, Saint Bernard18 min
May 10, 4:20 AM CDTFlash Flood WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard115 min
May 10, 5:26 AM CDTSpecial Marine WarningLIX64 min
May 10, 5:29 AM CDTSpecial Marine WarningLIX2 hr
May 10, 5:38 AM CDTSpecial Weather StatementLIXWest Baton Rouge67 min
May 10, 6:04 AM CDTSpecial Weather StatementLIXEast Baton Rouge, West Baton Rouge56 min
May 10, 6:16 AM CDTSpecial Weather StatementLIXSaint Charles44 min
May 10, 6:36 AM CDTSpecial Marine WarningLIX54 min
May 10, 7:25 AM CDTSpecial Weather StatementLIXSaint John the Baptist50 min
May 10, 7:34 AM CDTSpecial Marine WarningLIX56 min
May 10, 7:51 AM CDTSevere Thunderstorm WarningLIXIberville, Pointe Coupee, West Baton Rouge54 min
May 10, 8:23 AM CDTSpecial Marine WarningLIX67 min
May 10, 8:28 AM CDTSevere Thunderstorm WarningLIXAscension, East Baton Rouge, Iberville, Livingston, Pointe Coupee, West Baton Rouge62 min
May 10, 9:38 AM CDTTornado WarningLIXAscension, Livingston, Saint James, Saint John the Baptist20 min
May 10, 9:57 AM CDTSpecial Weather StatementLIXAssumption, Orleans, Saint Charles, Saint James, Saint John the Baptist, Saint Tammany63 min
May 10, 10:29 AM CDTSpecial Marine WarningLIX61 min
May 10, 11:08 AM CDTSpecial Weather StatementLIXOrleans52 min
May 10, 11:17 AM CDTSpecial Marine WarningLIX58 min
May 10, 12:10 PM CDTSpecial Marine WarningLIX65 min
May 10, 12:14 PM CDTSpecial Marine WarningLIX91 min
May 10, 1:08 PM CDTSpecial Marine WarningLIX67 min
May 10, 1:44 PM CDTSpecial Marine WarningLIX28 min
May 10, 2:09 PM CDTSpecial Marine WarningLIX66 min
May 10, 3:09 PM CDTSpecial Marine WarningLIX96 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.