Alert archive / Louisiana / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 94, NWS New Orleans, LA

May 4, 2021Saint John the Baptist Parish, Tangipahoa Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at May 4, 2021, 10:28 PM CDT for Saint John the Baptist Parish, Tangipahoa Parish, Louisiana. It was in force for 5 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, 10:28 PM CDT (03:28 UTC)
Expired
May 4, 2021, 10:33 PM CDT
In force
5 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Hail
0.75 in
Wind
60.0 mph

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

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 00:00Z, 3.5 hours before the alert went out and 64 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 2021-05-05Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 3152 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 2021-05-05The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 120 square meters per square second.1939587897Sfc1 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
3152 J/kg
Mixed-layer CIN
-1 J/kg
Mixed-layer LCL
647 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
120 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
3.1
Supercell composite
10.5

Open this sounding in Storm Lab

The text

As transmitted.

328 
WUUS54 KLIX 050328
SVRLIX
LAC095-105-050415-
/O.NEW.KLIX.SV.W.0094.210505T0328Z-210505T0415Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service New Orleans LA
1028 PM CDT Tue May 4 2021

The National Weather Service in New Orleans has issued a

* Severe Thunderstorm Warning for...
  Northeastern St. John The Baptist Parish in southeastern
  Louisiana...
  Southern Tangipahoa Parish in southeastern Louisiana...

* Until 1115 PM CDT.

* At 1027 PM CDT, a severe thunderstorm was located 11 miles south of
  Ponchatoula, or 14 miles north of Laplace, moving east at 25 mph.

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

  SOURCE...Radar indicated.

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

* This severe thunderstorm will remain over mainly rural areas of
  northeastern St. John The Baptist and southern Tangipahoa Parishes.

This includes Interstate 55 in Louisiana between mile markers 12 and
16.
 
PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3042 9031 3030 9030 3024 9036 3024 9043
      3028 9041 3041 9040
TIME...MOT...LOC 0327Z 267DEG 23KT 3027 9043 

HAIL...0.75IN
WIND...60MPH
 
$$

23
1 follow-up statement
681 
WWUS54 KLIX 050333
SVSLIX

Severe Weather Statement
National Weather Service New Orleans LA
1033 PM CDT Tue May 4 2021

LAC095-105-050343-
/O.CAN.KLIX.SV.W.0094.000000T0000Z-210505T0415Z/
St. John The Baptist LA-Tangipahoa LA-
1033 PM CDT Tue May 4 2021

...THE SEVERE THUNDERSTORM WARNING FOR NORTHEASTERN ST. JOHN THE
BAPTIST AND SOUTHERN TANGIPAHOA PARISHES IS CANCELLED...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning has
been cancelled.

LAT...LON 3042 9031 3030 9030 3024 9036 3024 9043
      3028 9041 3041 9040
TIME...MOT...LOC 0332Z 267DEG 23KT 3027 9039 

$$

The office that day

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

IssuedProductOfficeCountiesLasted
May 4, 7:21 PM CDTSpecial Marine WarningLIX54 min
May 4, 8:03 PM CDTSpecial Weather StatementLIXTangipahoa27 min
May 4, 8:13 PM CDTSpecial Weather StatementLIXWashington17 min
May 4, 8:21 PM CDTSpecial Marine WarningLIX54 min
May 4, 9:06 PM CDTRiver Flood WarningLIXSaint Tammany69 hr
May 4, 10:03 PM CDTSevere Thunderstorm WarningLIXLivingston, Saint John the Baptist, Tangipahoa27 min
May 4, 10:06 PM CDTSpecial Marine WarningLIX24 min
May 4, 10:25 PM CDTSpecial Marine WarningLIX65 min
May 5, 12:47 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Saint Bernard, Saint Charles, Saint James, Saint John the Baptist103 min
May 5, 1:15 AM CDTSpecial Weather StatementLIXOrleans45 min
May 5, 4:24 AM CDTAreal Flood AdvisoryLIXSaint Tammany3 hr
May 5, 6:16 AM CDTRiver Flood WarningLIXSaint Tammany25 hr
May 5, 6:45 AM CDTAreal Flood AdvisoryLIXSaint Charles, Saint James, Saint John the Baptist2 hr
May 5, 7:01 AM CDTFlash Flood WarningLIXSaint Tammany89 min
May 5, 7:20 AM CDTFlash Flood WarningLIXSaint Charles, Saint James, Saint John the Baptist115 min
May 5, 7:39 AM CDTSpecial Marine WarningLIX36 min
May 5, 7:48 AM CDTAreal Flood AdvisoryLIXOrleans, Saint Tammany117 min
May 5, 8:00 AM CDTAreal Flood AdvisoryLIXJefferson, Orleans, Plaquemines, Saint Bernard, Saint Charles2 hr
May 5, 8:25 AM CDTFlash Flood WarningLIXJefferson, Orleans, Plaquemines, Saint Bernard2 hr
May 5, 9:23 AM CDTSpecial Marine WarningLIX67 min
May 5, 10:25 AM CDTSpecial Marine WarningLIX50 min
May 5, 10:31 AM CDTSpecial Marine WarningLIX59 min
May 5, 11:11 AM CDTSpecial Marine WarningLIX49 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.