Alert archive / Louisiana / Special Weather Statements in 2021

Special Weather Statement, NWS New Orleans, LA

July 25, 2021Saint Tammany Parish, Louisiana; Hancock County, Mississippi

NWS New Orleans, LA issued this special weather statement at Jul 25, 2021, 1:55 PM CDT for Saint Tammany Parish, Louisiana; Hancock County, Mississippi. It was in force for 95 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
Jul 25, 2021, 1:55 PM CDT (18:55 UTC)
Expired
Jul 25, 2021, 3:30 PM CDT
In force
95 min
Issued by
NWS New Orleans, LA

Counties Saint Tammany Parish, LA, Hancock County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 6.9 hours before the alert went out and 15 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 2021-07-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2216 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 2021-07-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -11 square meters per square second.1939Sfc1 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
2216 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
793 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-11 m²/s²
0-3 km storm-relative helicity
0 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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What forecasters said that day

The local office's own words before this special weather statement went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS New Orleans, LA wrote its last area forecast discussion before this special weather statement went out at Jul 25, 12:32 PM CDT, 1 hour 23 minutes earlier.

Area forecast discussion, Jul 25, 12:32 PM CDT, 1 hour 23 minutes before
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<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
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  <link rel="stylesheet" href="index.css">
</head>
<body>
  <main class="wrap">
    <section class="card" role="status" aria-live="polite">
      <div class="status" id="status">Temporary Notice</div>
      <h1 id="headline">This service is currently unavailable.</h1>
      <p id="message1">
        The site you requested is temporarily down for maintenance or an unexpected outage.
      </p>
      <p id="message2">
        Please try again in a few minutes.
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        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
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In the hours before

Special weather statement, Jul 25, 10:53 AM CDT, 3 hours 2 minutes before
Special Weather Statement
National Weather Service New Orleans LA
1053 AM CDT Sun Jul 25 2021

LAZ068-069-251645-
Lower Plaquemines-Lower Jefferson-
1053 AM CDT Sun Jul 25 2021

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT EAST CENTRAL JEFFERSON
AND WEST CENTRAL PLAQUEMINES PARISHES...

At 1053 AM CDT, strong thunderstorms were clustered 9 miles southwest
of Port Sulphur. The storm is nearly stationary.

Winds in excess of 30 mph are possible with this storm.

Locations impacted include...
Port Sulphur.

Conditions in the atmosphere are such that weak, brief funnels may
form with these storms. These funnels are usually harmless, but on
rare occasions can briefly touch down and cause wind gusts over 50
mph. If a funnel approaches your location, move indoors.

Please contact the National Weather Service if you see a funnel.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 2942 8978 2936 8987 2943 8981 2941 8987
      2945 8982 2948 8984 2948 8985 2946 8989
      2943 8988 2942 8994 2949 8989 2949 8993
      2944 8993 2947 8997 2944 8999 2959 9006
      2955 8976 2938 8974 2935 8983
TIME...MOT...LOC 1553Z 144DEG 2KT 2942 8985

CAB
Local storm report, Jul 25, 11:52 AM CDT, 2 hours 3 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1152 AM CDT SUN JUL 25 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0906 AM     WATER SPOUT      2 ESE GRAND ISLE        29.23N 89.95W
07/25/2021                   GMZ552             LA   BROADCAST MEDIA

            A FEW WATERSPOUTS OCCURRED SOUTH OF GRAND
            ISLE. RELAYED VIA SOCIAL MEDIA.

&&
Special weather statement, Jul 25, 11:53 AM CDT, 2 hours 2 minutes before
Special Weather Statement
National Weather Service New Orleans LA
1153 AM CDT Sun Jul 25 2021

LAZ059>061-067>069-251730-
Lower Plaquemines-St. Charles-Lower Jefferson-Lower Lafourche-Upper
Lafourche-Upper Jefferson-
1153 AM CDT Sun Jul 25 2021

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT SOUTH CENTRAL ST.
CHARLES...EAST CENTRAL LAFOURCHE...CENTRAL JEFFERSON AND NORTHWESTERN
PLAQUEMINES PARISHES...

At 1139 AM CDT, strong thunderstorms were clustered near Larose. The
storm is nearly stationary.

Winds in excess of 30 mph are possible with this storm.

Locations impacted include...
Larose, Cut Off, Galliano, Lockport, Mathews, Lafitte and Raceland.

Conditions in the atmosphere are such that weak, brief funnels may
form with these storms. These funnels are usually harmless, but on
rare occasions can briefly touch down and cause wind gusts over 50
mph. If a funnel approaches your location, move indoors.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 2946 9048 2972 9059 2973 9027 2956 8988
      2938 9041
TIME...MOT...LOC 1639Z 145DEG 2KT 2967 9037

CAB
Special weather statement, Jul 25, 12:08 PM CDT, 1 hour 47 minutes before
Special Weather Statement
National Weather Service New Orleans LA
1208 PM CDT Sun Jul 25 2021

LAZ061-063-069-070-251800-
Lower Plaquemines-Lower St. Bernard-Upper Plaquemines-Upper
Jefferson-
1208 PM CDT Sun Jul 25 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN ST. BERNARD...
CENTRAL JEFFERSON AND NORTHWESTERN PLAQUEMINES PARISHES...

At 1206 PM CDT, a strong thunderstorm was located 7 miles north of
Pointe A La Hache, or 13 miles northwest of Port Sulphur, moving
northwest at 10 mph.

Winds in excess of 30 mph are possible with this storm.

Locations impacted include...
Jean Lafitte, Myrtle Grove, Lafitte and Barataria.

Conditions in the atmosphere are such that weak, brief funnels may
form with these storms. These funnels are usually harmless, but on
rare occasions can briefly touch down and cause wind gusts over 50
mph. If a funnel approaches your location, move indoors.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 2962 8999 2962 9001 2971 9021 2980 8987
      2979 8985 2980 8985 2982 8979 2967 8961
      2966 8963 2968 8964 2968 8966 2966 8967
      2966 8965 2956 8988
TIME...MOT...LOC 1706Z 112DEG 8KT 2968 8982

CAB
Special weather statement, Jul 25, 1:47 PM CDT, 8 minutes before
Special Weather Statement
National Weather Service New Orleans LA
147 PM CDT Sun Jul 25 2021

MSZ077-080-251945-
Hancock-Pearl River-
147 PM CDT Sun Jul 25 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTH CENTRAL HANCOCK AND
SOUTHWESTERN PEARL RIVER COUNTIES...

At 146 PM CDT, a strong thunderstorm was located near Mcneil, or 11
miles northeast of Picayune, moving west at 10 mph.

Winds in excess of 30 mph are possible with this storm.

Locations impacted include...
Picayune, Crossroads and Mcneil.

This includes Interstate 59 in Mississippi between mile markers 7 and
21.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 3073 8947 3056 8944 3053 8977 3056 8981
      3057 8979 3062 8983 3064 8982 3067 8984
      3069 8985 3072 8983 3076 8983 3079 8982
      3080 8981
TIME...MOT...LOC 1846Z 080DEG 7KT 3064 8954

CAB
Special weather statement, Jul 25, 1:55 PM CDT, 0 minutes before
Special Weather Statement
National Weather Service New Orleans LA
155 PM CDT Sun Jul 25 2021

LAZ075-076-MSZ077-080-252030-
Southeast St. Tammany-Northwest St. Tammany-Hancock-Pearl River-
155 PM CDT Sun Jul 25 2021

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT CENTRAL ST. TAMMANY
PARISH...CENTRAL HANCOCK AND SOUTH CENTRAL PEARL RIVER COUNTIES...

At 154 PM CDT, strong thunderstorms were clustered over Stennis Space
Center, or 12 miles southeast of Picayune, moving west at 10 mph.

Winds in excess of 30 mph and frequent cloud to ground lightning
is possible with these storms.

Locations impacted include...
Slidell, Picayune, Covington, Pearl River, Abita Springs, Kiln,
Pearlington, Lacombe, Stennis Space Center, Shoreline Park and
Slidell Airport.

This includes the following Interstates...
 Interstate 10 in Louisiana between mile markers 261 and 273.
 Interstate 10 in Mississippi between mile markers 1 and 12.
 Interstate 12 between mile markers 61 and 84.
 Interstate 59 in Louisiana between mile markers 1 and 11.
 Interstate 59 in Mississippi between mile markers 1 and 6.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

LAT...LON 3027 8941 3021 8981 3022 8985 3025 8987
      3025 8993 3026 8995 3026 8998 3029 8998
      3036 9007 3037 9012 3052 9013 3055 8944
TIME...MOT...LOC 1854Z 080DEG 7KT 3037 8959

CAB

The office that day

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

IssuedProductOfficeCountiesLasted
Jul 24, 7:46 PM CDTSpecial Weather StatementLIXLafourche44 min
Jul 25, 3:28 AM CDTSpecial Marine WarningLIX62 min
Jul 25, 4:30 AM CDTSpecial Marine WarningLIX60 min
Jul 25, 5:30 AM CDTSpecial Marine WarningLIX60 min
Jul 25, 6:31 AM CDTSpecial Marine WarningLIX59 min
Jul 25, 7:30 AM CDTSpecial Marine WarningLIX60 min
Jul 25, 10:22 AM CDTSpecial Marine WarningLIX98 min
Jul 25, 10:48 AM CDTSpecial Marine WarningLIX57 min
Jul 25, 10:53 AM CDTSpecial Weather StatementLIXJefferson52 min
Jul 25, 11:53 AM CDTSpecial Weather StatementLIXLafourche37 min
Jul 25, 12:08 PM CDTSpecial Weather StatementLIXJefferson52 min
Jul 25, 2:08 PM CDTAreal Flood AdvisoryLIXSaint Tammany80 min
Jul 25, 3:20 PM CDTHeat AdvisoryLIXAssumption, East Baton Rouge, East Feliciana, Iberville, Orleans, Pointe Coupee and 9 more28 hr
Jul 25, 1:47 PM CDTSpecial Weather StatementLIXPearl River58 min

Nearby

Special Weather Statements in Louisiana, 2021Special Weather Statements in Mississippi, 2021Every special weather statement 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.