Alert archive / Louisiana / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 129, NWS New Orleans, LA

July 30, 2015Ascension Parish, Livingston Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at Jul 30, 2015, 3:42 PM CDT for Ascension Parish, Livingston Parish, Louisiana. It was in force for 48 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued: Jul 30, 2015, 3:42 PM CDT (20:42 UTC)
Expired: Jul 30, 2015, 4:30 PM CDT
In force: 48 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon

Counties Ascension Parish, LA, Livingston Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 8.7 hours before the alert went out and 108 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: 544 J/kg
Mixed-layer CIN: -122 J/kg
Mixed-layer LCL: 1224 m above ground
0-6 km bulk shear: 10 kt
0-1 km storm-relative helicity: 60 m²/s²
0-3 km storm-relative helicity: 86 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning 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 severe thunderstorm warning went out at Jul 30, 3:27 PM CDT, 15 minutes earlier.

Area forecast discussion, Jul 30, 3:27 PM CDT, 15 minutes before

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <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.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

Hazardous weather outlook, Jul 30, 12:09 PM CDT, 3 hours 33 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE NEW ORLEANS LA
1209 PM CDT THU JUL 30 2015

GMZ530-532-534-536-538-550-552-555-557-570-572-575-577-LAZ034>037-
039-040-046>050-056>072-MSZ068>071-077-080>082-310515-
LAKE PONTCHARTRAIN AND LAKE MAUREPAS-MISSISSIPPI SOUND-
LAKE BORGNE-CHANDELEUR SOUND-BRETON SOUND-
COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER OUT
20 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO PORT FOURCHON OUT 20 NM-
COASTAL WATERS FROM BOOTHVILLE LA TO THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER OUT 20 NM-
COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA OUT 20 NM-
COASTAL WATERS FROM PORT FOURCHON TO LOWER ATCHAFALAYA RIVER FROM
20 TO 60 NM-
COASTAL WATERS FROM THE SOUTHWEST PASS OF THE MISSISSIPPI RIVER
TO PORT FOURCHON FROM 20 TO 60 NM-
COASTAL WATERS FROM STAKE ISLAND LA TO THE SOUTHWEST PASS OF THE
MISSISSIPPI RIVER FROM 20 TO 60 NM-
COASTAL WATERS FROM PASCAGOULA MS TO STAKE ISLAND LA FROM 20 TO
60 NM-POINTE COUPEE-WEST FELICIANA-EAST FELICIANA-ST. HELENA-
WASHINGTON-ST. TAMMANY-IBERVILLE-WEST BATON ROUGE-
EAST BATON ROUGE-ASCENSION-LIVINGSTON-ASSUMPTION-ST. JAMES-
ST. JOHN THE BAPTIST-UPPER LAFOURCHE-ST. CHARLES-UPPER JEFFERSON-
ORLEANS-UPPER PLAQUEMINES-UPPER ST. BERNARD-UPPER TERREBONNE-
LOWER TERREBONNE-LOWER LAFOURCHE-LOWER JEFFERSON-
LOWER PLAQUEMINES-LOWER ST. BERNARD-NORTHERN TANGIPAHOA-
SOUTHERN TANGIPAHOA-WILKINSON-AMITE-PIKE-WALTHALL-PEARL RIVER-
HANCOCK-HARRISON-JACKSON-
1209 PM CDT THU JUL 30 2015

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST
LOUISIANA...SOUTH MISSISSIPPI AND THE ADJACENT COASTAL WATERS.

.DAY ONE...THIS AFTERNOON AND TONIGHT

HEAT INDEX VALUES 105 TO 113 ARE EXPECTED ACROSS MUCH OF THE
REGION AND WITH THAT A HEAT ADVISORY IS NOW IN PLACE THROUGH 6 PM
FOR AREAS MAINLY ALONG AND NORTH OF A LINE FROM HOUMA TO NEW
ORLEANS TO PASCAGOULA.

SCATTERED THUNDERSTORMS WILL PROVIDE SOME RELIEF FROM THE HEAT
LATER THIS AFTERNOON THROUGH THIS EVENING. SOME OF THE STORMS
COULD BE STRONG TO MARGINALLY SEVERE AND PRODUCE STRONG GUSTY
WINDS...FREQUENT LIGHTNING AND BRIEF HEAVY DOWNPOURS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY

HEAT INDICES ARE EXPECTED TO CONTINUE TO REACH NEAR TO SLIGHTLY
ABOVE 105 DEGREES EACH AFTERNOON.

THERE IS A GOOD CHANCE OF THUNDERSTORMS ON FRIDAY. SOME OF THE
STORMS COULD BE STRONG TO MARGINALLY SEVERE AND PRODUCE STRONG
GUSTY WINDS...FREQUENT LIGHTNING AND BRIEF HEAVY DOWNPOURS.
THUNDERSTORMS ARE EXPECTED TO BECOME MORE ISOLATED IN COVERAGE
SATURDAY THROUGH TUESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS NOT ANTICIPATED.

CAB

In the hours before

Special weather statement, Jul 30, 1:39 PM CDT, 2 hours 3 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
139 PM CDT THU JUL 30 2015

LAZ039-MSZ071-301930-
WASHINGTON LA-WALTHALL MS-
139 PM CDT THU JUL 30 2015

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN WASHINGTON PARISH IN
SOUTHEASTERN LOUISIANA AND SOUTHEASTERN WALTHALL COUNTIES UNTIL 230
PM CDT...

AT 139 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
PICKWICK...OR NEAR SANDY HOOK...MOVING SOUTH AT 15 MPH.

WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
VARNADO...DEXTER AND ANGIE.

LAT...LON 3111 8994 3111 8993 3107 8992 3108 8984
      3100 8983 3100 8974 3096 8973 3095 8976
      3092 8974 3091 8976 3090 8976 3090 8977
      3088 8977 3088 9003 3113 8999 3113 8994
TIME...MOT...LOC 1839Z 000DEG 14KT 3110 8988

CAB

Special weather statement, Jul 30, 2:06 PM CDT, 1 hour 36 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
206 PM CDT THU JUL 30 2015

LAZ036-037-MSZ069-301945-
EAST FELICIANA LA-ST. HELENA LA-AMITE MS-
206 PM CDT THU JUL 30 2015

...SIGNIFICANT WEATHER ADVISORY FOR NORTHWESTERN ST. HELENA...
NORTHEASTERN EAST FELICIANA PARISHES IN SOUTHEASTERN LOUISIANA AND
SOUTHWESTERN AMITE COUNTIES UNTIL 245 PM CDT...

AT 204 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM NEAR LIBERTY...MOVING SOUTH AT 30 MPH.

HALF INCH HAIL AND WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH
THIS STORM.

LOCATIONS IMPACTED INCLUDE...
CLINTON...LIBERTY...DARLINGTON AND FELPS.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO PONDING OF WATER IN LOW LYING ROADWAYS AND IN AREAS OF POOR
DRAINAGE.

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO AND
TV STATIONS...AS WELL AS LOCAL CABLE TV OUTLETS...FOR ADDITIONAL
INFORMATION AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

&&

LAT...LON 3124 9091 3120 9071 3073 9077 3078 9108
TIME...MOT...LOC 1904Z 012DEG 24KT 3115 9083

95/DM

Special weather statement, Jul 30, 2:40 PM CDT, 1 hour 2 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
240 PM CDT THU JUL 30 2015

MSZ069-070-302030-
PIKE MS-AMITE MS-
240 PM CDT THU JUL 30 2015

...SIGNIFICANT WEATHER ADVISORY FOR EASTERN AMITE AND PIKE COUNTIES
UNTIL 330 PM CDT...

AT 239 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
SUMMIT...OR 7 MILES NORTH OF MCCOMB...MOVING SOUTHWEST AT 20 MPH.

WINDS IN EXCESS OF 40 MPH WILL BE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
MCCOMB...MAGNOLIA...SUMMIT...OSYKA...GILLSBERG AND MCCOMB AIRPORT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY LEAD
TO FLASH FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

FREQUENT CLOUD TO GROUND LIGHTNING IS OCCURRING WITH THIS STORM.
LIGHTNING CAN STRIKE 15 MILES AWAY FROM A THUNDERSTORM. SEEK A SAFE
SHELTER INSIDE A BUILDING OR VEHICLE.

&&

LAT...LON 3101 9028 3101 9087 3135 9065 3135 9026
TIME...MOT...LOC 1939Z 034DEG 19KT 3135 9044

Local storm report, Jul 30, 3:29 PM CDT, 13 minutes before

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Service Notice</title>
  <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.
      </p>
      <p class="small" id="detail">
        If you are an administrator, restore upstream service and remove the redirect/fallback rule when normal operations resume.
      </p>
    </section>
  </main>
  <script src="index.js"></script>
</body>
</html>

The office that day

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

Issued	Product	Office	Counties	Lasted
Jul 29, 7:19 PM CDT	Special Weather Statement	LIX	Jefferson	41 min
Jul 29, 7:24 PM CDT	Special Weather Statement	LIX	Washington	36 min
Jul 29, 7:39 PM CDT	Special Weather Statement	LIX	Saint Charles	51 min
Jul 29, 8:17 PM CDT	Special Weather Statement	LIX	Saint Tammany, Tangipahoa	43 min
Jul 29, 8:30 PM CDT	Special Weather Statement	LIX	Lafourche	45 min
Jul 29, 8:50 PM CDT	Special Marine Warning	LIX		55 min
Jul 30, 11:49 AM CDT	Heat Advisory	LIX	Assumption, East Baton Rouge, East Feliciana, Iberville, Pointe Coupee, Saint Bernard and 7 more	6 hr
Jul 30, 1:39 PM CDT	Special Weather Statement	LIX	Washington	51 min
Jul 30, 2:06 PM CDT	Special Weather Statement	LIX	East Feliciana	39 min
Jul 30, 3:07 PM CDT	Severe Thunderstorm Warning	LIX	Saint Tammany	23 min
Jul 30, 3:17 PM CDT	Severe Thunderstorm Warning	LIX	Tangipahoa	43 min
Jul 30, 3:20 PM CDT	Severe Thunderstorm Warning	LIX	East Feliciana, Pointe Coupee, West Feliciana	40 min
Jul 30, 3:32 PM CDT	Severe Thunderstorm Warning	LIX	East Baton Rouge	43 min
Jul 30, 3:34 PM CDT	Severe Thunderstorm Warning	LIX	Saint Tammany	41 min
Jul 30, 3:49 PM CDT	Special Marine Warning	LIX		56 min
Jul 30, 3:57 PM CDT	Severe Thunderstorm Warning	LIX	Iberville, Pointe Coupee, West Baton Rouge	48 min
Jul 30, 4:01 PM CDT	Severe Thunderstorm Warning	LIX	Ascension, Livingston, Saint James, Saint John the Baptist	29 min
Jul 30, 4:19 PM CDT	Special Weather Statement	LIX	Saint Charles	26 min
Jul 30, 4:27 PM CDT	Special Weather Statement	LIX	Iberville	33 min
Jul 30, 4:37 PM CDT	Special Weather Statement	LIX	Assumption, Saint James	38 min
Jul 30, 5:15 PM CDT	Special Marine Warning	LIX		30 min
Jul 30, 5:23 PM CDT	Special Weather Statement	LIX	St. Mary	52 min
Jul 30, 5:42 PM CDT	Special Marine Warning	LIX		63 min
Jul 30, 6:02 PM CDT	Special Weather Statement	LIX	Lafourche	43 min
Jul 30, 6:06 PM CDT	Special Marine Warning	LIX		54 min
Jul 30, 6:10 PM CDT	Special Marine Warning	LIX		65 min
Jul 30, 6:23 PM CDT	Special Marine Warning	LIX		37 min
Jul 30, 6:28 PM CDT	Special Marine Warning	LIX		62 min
Jul 30, 2:40 PM CDT	Special Weather Statement	LIX	Pike	50 min
Jul 30, 3:00 PM CDT	Severe Thunderstorm Warning	LIX	Walthall	45 min
Jul 30, 3:45 PM CDT	Severe Thunderstorm Warning	LIX	Hancock, Pearl River	45 min
Jul 30, 5:06 PM CDT	Special Weather Statement	LIX	Hancock	24 min
Jul 30, 5:30 PM CDT	Special Weather Statement	LIX	Harrison	30 min
Jul 30, 5:51 PM CDT	Special Weather Statement	LIX	Pike	24 min
Jul 30, 6:08 PM CDT	Special Weather Statement	LIX	Jackson	37 min
Jul 30, 6:15 PM CDT	Special Weather Statement	LIX	Amite	45 min
Jul 30, 6:47 PM CDT	Special Weather Statement	LIX	Amite	28 min
Jul 30, 6:50 PM CDT	Special Weather Statement	LIX	Jackson	25 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2015 Every severe thunderstorm warning in 2015

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.