Alert archive / Louisiana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 3, NWS New Orleans, LA

March 17, 20217 parishes in Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Mar 17, 2021, 4:05 PM CDT for 7 parishes in Louisiana. It was in force for 40 min. 2 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Mar 17, 2021, 4:05 PM CDT (21:05 UTC)
Expired: Mar 17, 2021, 4:45 PM CDT
In force: 40 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon
Tornado: Possible
Hail: 0.75 in
Wind: 70.0 mph

Counties Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Saint James Parish, LA, West Baton Rouge Parish, LA

What was reported inside it

Time	Report	Where	Remark
Mar 17, 4:27 PM CDT	TSTM WND DMG	1 S Denham Springs, LA	PUBLIC REPORTED VIA SOCIAL MEDIA ABOUT A FALLEN TREE IN DENHAM SPRINGS ON HWY 447/WALKER S RD AND BOTH NB/SB OF HAMMACK RD/HOOD RD.
Mar 17, 4:32 PM CDT	TSTM WND DMG	3 Ene Oak Hills Place, LA	REPORT FROM EAST BATON ROUGE PARISH ABOUT POWER LINE DOWN AND TREE ON VEHICLE NEAR JEFFERSON AND STUMBERG BY TIGER BEND.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Mar 17, 2:38 PM CDT	Tornado Watch	SPC	8 hr

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 9.1 hours before the alert went out and 156 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: 1786 J/kg
Mixed-layer CIN: -40 J/kg
Mixed-layer LCL: 644 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 205 m²/s²
0-3 km storm-relative helicity: 396 m²/s²
Significant tornado parameter: 2.0
Supercell composite: 9.9

Open this sounding in Storm Lab

The text

As transmitted.

337 
WUUS54 KLIX 172105
SVRLIX
LAC005-007-033-047-063-093-121-172145-
/O.NEW.KLIX.SV.W.0003.210317T2105Z-210317T2145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service New Orleans LA
405 PM CDT Wed Mar 17 2021

The National Weather Service in New Orleans has issued a

* Severe Thunderstorm Warning for...
  Ascension Parish in southeastern Louisiana...
  West central St. James Parish in southeastern Louisiana...
  West Baton Rouge Parish in southeastern Louisiana...
  Northwestern Livingston Parish in southeastern Louisiana...
  Iberville Parish in southeastern Louisiana...
  Southwestern East Baton Rouge Parish in southeastern Louisiana...
  Assumption Parish in southeastern Louisiana...

* Until 445 PM CDT.

* At 405 PM CDT, severe thunderstorms were located along a line
  extending from near Butte La Rose to near Glencoe, moving northeast
  at 70 mph.

  HAZARD...70 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...Expect considerable tree damage. Damage is likely to 
           mobile homes, roofs, and outbuildings.

* Locations impacted include...
  Baton Rouge, Denham Springs, Gonzales, Donaldsonville, Plaquemine,
  Port Allen, Napoleonville, Oak Hills Place, St. Gabriel, Walker,
  Addis, Brusly, White Castle, Rosedale, Grosse Tete, Westminster,
  Geismar, Watson, Supreme and Ramah.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM CDT for southeastern
Louisiana.

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

&&

LAT...LON 3040 9163 3065 9080 2984 9095 2982 9111
      2985 9118 2992 9123 3000 9126 3000 9123
      3004 9122 3003 9124 3006 9127 3006 9137
      3010 9138 3010 9146 3023 9148 3026 9159
      3038 9164
TIME...MOT...LOC 2105Z 244DEG 59KT 3027 9159 2984 9169 

TORNADO...POSSIBLE
HAIL...<.75IN
WIND...70MPH
 
$$

KLG

1 follow-up statement

518 
WWUS54 KLIX 172129
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
429 PM CDT Wed Mar 17 2021

LAC005-007-033-047-063-093-121-172145-
/O.CON.KLIX.SV.W.0003.000000T0000Z-210317T2145Z/
Ascension LA-St. James LA-West Baton Rouge LA-Livingston LA-
Iberville LA-East Baton Rouge LA-Assumption LA-
429 PM CDT Wed Mar 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 445 PM CDT
FOR ASCENSION...WEST CENTRAL ST. JAMES...SOUTHEASTERN WEST BATON
ROUGE...NORTHWESTERN LIVINGSTON...IBERVILLE...SOUTHWESTERN EAST BATON
ROUGE AND NORTHERN ASSUMPTION PARISHES...

At 429 PM CDT, severe thunderstorms were located along a line
extending from Baton Rouge to 8 miles northwest of Pierre Part,
moving northeast at 75 mph.

HAZARD...70 mph wind gusts and penny size hail.

SOURCE...Radar indicated.

IMPACT...Expect considerable tree damage. Damage is likely to mobile 
         homes, roofs, and outbuildings.

Locations impacted include...
Baton Rouge, Denham Springs, Gonzales, Donaldsonville, Plaquemine,
Port Allen, Oak Hills Place, St. Gabriel, Walker, Addis, Brusly,
White Castle, Westminster, Geismar, Watson, Bayou Sorrel, Shenandoah,
Greenwell Spring, Old Jefferson and Merrydale.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 900 PM CDT for southeastern
Louisiana.

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

&&

LAT...LON 2999 9092 2992 9123 3000 9126 3000 9123
      3004 9122 3004 9125 3006 9127 3006 9137
      3010 9138 3010 9146 3023 9148 3030 9136
      3049 9134 3065 9080
TIME...MOT...LOC 2129Z 241DEG 65KT 3045 9115 3003 9133 

TORNADO...POSSIBLE
HAIL...0.75IN
WIND...70MPH
 
$$

KLG

The office that day

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

Issued	Product	Office	Counties	Lasted
Mar 17, 3:33 AM CDT	Wind Advisory	LIX	Assumption, East Baton Rouge, Iberville, Saint Bernard, Saint James, Saint John the Baptist and 1 more	18 hr
Mar 17, 3:18 PM CDT	Special Weather Statement	LIX	Pointe Coupee, West Feliciana	42 min
Mar 17, 3:30 PM CDT	Tornado Warning	LIX	Pointe Coupee, West Feliciana	45 min
Mar 17, 4:44 PM CDT	Severe Thunderstorm Warning	LIX	Ascension, East Baton Rouge, Iberville, Livingston, Saint Helena, Tangipahoa	34 min
Mar 17, 4:50 PM CDT	Special Weather Statement	LIX	East Feliciana, Saint Helena	55 min
Mar 17, 5:06 PM CDT	Special Weather Statement	LIX	Ascension, Iberville	39 min
Mar 17, 5:11 PM CDT	Special Weather Statement	LIX	Ascension, Livingston, Tangipahoa	49 min
Mar 17, 5:29 PM CDT	Special Weather Statement	LIX	Washington	46 min
Mar 17, 5:40 PM CDT	Severe Thunderstorm Warning	LIX	Washington	31 min
Mar 17, 5:59 PM CDT	Areal Flood Advisory	LIX	Ascension, Assumption, East Baton Rouge, Iberville, Livingston, Saint James and 2 more	3 hr
Mar 17, 6:05 PM CDT	Special Weather Statement	LIX	Livingston, Saint John the Baptist, Tangipahoa	55 min
Mar 17, 6:07 PM CDT	Special Marine Warning	LIX		53 min
Mar 17, 6:24 PM CDT	Areal Flood Advisory	LIX	Livingston, Saint John the Baptist, Saint Tammany, Tangipahoa	3 hr
Mar 17, 6:27 PM CDT	Severe Thunderstorm Warning	LIX	Ascension, Assumption, Iberville, Lafourche, Saint James, Terrebonne	63 min
Mar 17, 6:54 PM CDT	Special Weather Statement	LIX	Saint Tammany	66 min
Mar 17, 6:58 PM CDT	Special Marine Warning	LIX		62 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2021 Every 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive.