Alert archive / Louisiana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 91, NWS New Orleans, LA

May 4, 20216 parishes in Louisiana; 4 counties in Mississippi

NWS New Orleans, LA issued this severe thunderstorm warning at May 4, 2021, 3:33 PM CDT for 6 parishes in Louisiana; 4 counties in Mississippi. It was in force for 42 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 4, 2021, 3:33 PM CDT (20:33 UTC)
Expired
May 4, 2021, 4:15 PM CDT
In force
42 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties East Baton Rouge Parish, LA, East Feliciana Parish, LA, Saint Helena Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Feliciana Parish, LA, Amite County, MS, Pike County, MS, Walthall County, MS, Wilkinson County, MS

The watch it was issued in

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

IssuedProductOfficeLasted
May 4, 10:52 AM CDTTornado WatchSPC7 hr
May 4, 3:31 PM CDTTornado WatchSPC6 hr

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 8.6 hours before the alert went out and 117 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 2021-05-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2523 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 2021-05-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 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
2523 J/kg
Mixed-layer CIN
-43 J/kg
Mixed-layer LCL
594 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
192 m²/s²
Significant tornado parameter
1.1
Supercell composite
7.4

Open this sounding in Storm Lab

The text

As transmitted.

476 
WUUS54 KLIX 042033
SVRLIX
LAC033-037-091-105-117-125-MSC005-113-147-157-042115-
/O.NEW.KLIX.SV.W.0091.210504T2033Z-210504T2115Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service New Orleans LA
333 PM CDT Tue May 4 2021

The National Weather Service in New Orleans has issued a

* Severe Thunderstorm Warning for...
  St. Helena Parish in southeastern Louisiana...
  Southeastern West Feliciana Parish in southeastern Louisiana...
  East Feliciana Parish in southeastern Louisiana...
  Northern Tangipahoa Parish in southeastern Louisiana...
  Northeastern East Baton Rouge Parish in southeastern Louisiana...
  Northwestern Washington Parish in southeastern Louisiana...
  Walthall County in southern Mississippi...
  Pike County in southern Mississippi...
  Southeastern Wilkinson County in southern Mississippi...
  Amite County in southern Mississippi...

* Until 415 PM CDT.

* At 333 PM CDT, severe thunderstorms were located along a line
  extending from near Bogue Chitto to near Zachary, moving east at 50
  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...
  Zachary, Mccomb, Jackson, Clinton, Liberty, Greensburg, Amite,
  Amite City, Magnolia, Kentwood, Summit, Centreville, Tylertown,
  Roseland, Slaughter, Wilson, Osyka, Norwood, Montpelier and
  Smithdale.

This includes the following Interstates...
 Interstate 55 in Louisiana between mile markers 45 and 66.
 Interstate 55 in Mississippi between mile markers 1 and 24.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Tornado Watch remains in effect until 600 PM CDT for southeastern
Louisiana...and southern Mississippi. A Tornado Watch also remains in
effect until 1000 PM CDT for southeastern Louisiana...and southern
Mississippi.

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

&&

LAT...LON 3133 9008 3133 9004 3118 9003 3117 9000
      3114 9000 3068 9039 3070 9135 3072 9135
      3135 9085 3135 9011
TIME...MOT...LOC 2033Z 259DEG 45KT 3141 9050 3068 9111 

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

MSW

The office that day

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

IssuedProductOfficeCountiesLasted
May 4, 4:11 AM CDTFlash Flood WatchLIXAssumption, East Baton Rouge, East Feliciana, Iberville, Orleans, Pointe Coupee and 9 more33 hr
May 4, 9:54 AM CDTRiver Flood WarningLIXTangipahoa21 days
May 4, 2:26 PM CDTSevere Thunderstorm WarningLIXPointe Coupee, West Feliciana64 min
May 4, 2:58 PM CDTSevere Thunderstorm WarningLIXEast Feliciana, Pointe Coupee, West Feliciana47 min
May 4, 4:10 PM CDTSevere Thunderstorm WarningLIXEast Baton Rouge, East Feliciana, Saint Helena, Saint Tammany, Tangipahoa, Washington65 min
May 4, 4:24 PM CDTAreal Flood AdvisoryLIXEast Baton Rouge, East Feliciana, Livingston, Pointe Coupee, Saint Helena, West Baton Rouge and 1 more97 min
May 4, 4:37 PM CDTAreal Flood AdvisoryLIXEast Baton Rouge, East Feliciana, Livingston, Saint Helena, Tangipahoa, Washington106 min
May 4, 4:56 PM CDTSpecial Weather StatementLIXTangipahoa, Washington34 min
May 4, 5:32 PM CDTSpecial Weather StatementLIXTangipahoa, Washington43 min
May 4, 2:15 PM CDTSpecial Weather StatementLIXWilkinson30 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2021Severe Thunderstorm Warnings in Mississippi, 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.