Alert archive / Louisiana / Severe Thunderstorm Warnings in 2017

Severe Thunderstorm Warning 114, NWS New Orleans, LA

May 30, 2017Plaquemines Parish, Louisiana

NWS New Orleans, LA issued this severe thunderstorm warning at May 30, 2017, 4:42 PM CDT for Plaquemines Parish, Louisiana. It was in force for 63 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
May 30, 2017, 4:42 PM CDT (21:42 UTC)
Expired
May 30, 2017, 5:45 PM CDT
In force
63 min
Issued by
NWS New Orleans, LA
Area
Storm-based polygon
Tornado
Possible
Hail
0.75 in
Wind
60.0 mph

County Plaquemines Parish, LA

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 9.7 hours before the alert went out and 79 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 2017-05-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 296 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 2017-05-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 184 square meters per square second.193958Sfc1 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
296 J/kg
Mixed-layer CIN
-26 J/kg
Mixed-layer LCL
630 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
184 m²/s²
0-3 km storm-relative helicity
334 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 May 30, 3:41 PM CDT, 1 hour 1 minute earlier.

Area forecast discussion, May 30, 3:41 PM CDT, 1 hour 1 minute before
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Hazardous weather outlook, May 30, 11:13 AM CDT, 5 hours 29 minutes before
Hazardous Weather Outlook
National Weather Service New Orleans LA
1113 AM CDT Tue May 30 2017

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>082-310415-
Lake Pontchartrain and Lake Maurepas-Mississippi Sound-
Lake Borgne-Chandeleur Sound-Breton Sound-
Coastal Waters from Port Fourchon LA to Lower Atchafalaya River
LA out 20 nm-
Coastal waters from the Southwest Pass of the Mississippi River
to Port Fourchon Louisiana out 20 NM-
Coastal Waters from Boothville LA to Southwest Pass of the
Mississippi River out 20 nm-
Coastal waters from Pascagoula Mississippi to Stake Island out
20 NM-
Coastal waters from Port Fourchon Louisiana to Lower Atchafalaya
River LA from 20 to 60 NM-
Coastal waters from Southwest Pass of the Mississippi River to
Port Fourchon Louisiana from 20 to 60 NM-
Coastal Waters from Stake Island LA to Southwest Pass of the
Mississippi River from 20 to 60 nm-
Coastal waters from Pascagoula Mississippi to Stake Island
Louisiana out 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-
1113 AM CDT Tue May 30 2017

This Hazardous Weather Outlook is for portions of Southeast
Louisiana...South Mississippi and the adjacent coastal waters.

.DAY ONE...Today and Tonight

There is a Marginal Risk of severe thunderstorms through tonight
for an area from Baton Rouge to Slidell southward. All modes of
severe weather will be possible but the greatest threat is
expected to be damaging winds.

In addition, localized heavy rainfall is possible, especially for
areas south and west of Lake Pontchartrain. This could lead to
flooding of low lying and poor drainage areas.

.DAYS TWO THROUGH SEVEN...Wednesday through Monday

The chance for widespread hazardous weather is low. However...a
few strong thunderstorms could develop each day. These
thunderstorms could produce locally heavy downpours...gusty
winds...and frequent lightning strikes.

Some indications are pointing toward an even wetter pattern
possibly setting up for the weekend into Monday. This scenario
will be better refined through the remainder of this week.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not anticipated.

In the hours before

Special weather statement, May 30, 11:52 AM CDT, 4 hours 50 minutes before
Special Weather Statement
National Weather Service New Orleans LA
1152 AM CDT TUE MAY 30 2017

LAZ059-065-066-301745-
Lower Terrebonne-Upper Terrebonne-Upper Lafourche-
1152 AM CDT TUE MAY 30 2017

...A CLUSTER OF THUNDERSTORMS WILL AFFECT NORTHERN TERREBONNE AND
WEST CENTRAL LAFOURCHE PARISHES...

At 1150 AM CDT, thunderstorms were clustered 12 miles southwest of
Houma or central Terrebonne parish, moving northeast at 15 mph.

Locations impacted include...
Houma, Gray, Bayou Cane, Schriever and Dulac.

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

LAT...LON 2952 9120 2960 9107 2961 9107 2963 9108
      2965 9106 2977 9091 2959 9049 2956 9054
      2956 9057 2953 9057 2936 9082
TIME...MOT...LOC 1650Z 206DEG 18KT 2948 9088
Special weather statement, May 30, 12:51 PM CDT, 3 hours 51 minutes before
Special Weather Statement
National Weather Service New Orleans LA
1251 PM CDT TUE MAY 30 2017

LAZ059-060-066-067-301845-
Lower Terrebonne-St. Charles-Lower Lafourche-Upper Lafourche-
1251 PM CDT TUE MAY 30 2017

...AN AREA OF STRONG THUNDERSTORMS WILL AFFECT SOUTHWESTERN ST.
CHARLES...EAST CENTRAL TERREBONNE AND NORTH CENTRAL LAFOURCHE
PARISHES...

At 1250 PM CDT, strong thunderstorms were clustered over Montegut, or
10 miles southeast of Houma, moving northeast at 15 mph.

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

Locations impacted include...
Larose, Cut Off, Lockport, Mathews, Chauvin, Montegut, Raceland,
Bayou Gauche and Des Allemands.

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 2945 9070 2955 9065 2956 9057 2957 9060
      2960 9062 2960 9063 2983 9052 2970 9024
      2937 9051
TIME...MOT...LOC 1750Z 208DEG 14KT 2948 9057
Special weather statement, May 30, 1:28 PM CDT, 3 hours 14 minutes before
Special Weather Statement
National Weather Service New Orleans LA
128 PM CDT TUE MAY 30 2017

LAZ059-067-068-301900-
Lower Jefferson-Lower Lafourche-Upper Lafourche-
128 PM CDT TUE MAY 30 2017

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

At 128 PM CDT, strong thunderstorms were clustered near Galliano,
moving north at 10 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm.

Locations impacted include...
Larose, Cut Off, Galliano and Golden Meadow.

LAT...LON 2943 9045 2967 9040 2959 9016 2957 9016
      2958 9014 2957 9011 2937 9025
TIME...MOT...LOC 1828Z 200DEG 7KT 2948 9032
Special weather statement, May 30, 2:16 PM CDT, 2 hours 26 minutes before
Special Weather Statement
National Weather Service New Orleans LA
216 PM CDT TUE MAY 30 2017

LAZ059>061-067-068-301945-
St. Charles-Lower Jefferson-Lower Lafourche-Upper Lafourche-Upper
Jefferson-
216 PM CDT TUE MAY 30 2017

...A CLUSTER OF THUNDERSTORMS WILL AFFECT SOUTH CENTRAL ST.
CHARLES...EAST CENTRAL LAFOURCHE AND CENTRAL JEFFERSON PARISHES...

At 214 PM CDT, cluster of thunderstorms were clustered near Cut Off,
moving north at 5 mph.

Winds in excess of 30 mph and pea size hail are possible with this
storm.

Locations impacted include...
Cut Off, Larose and Lafitte.

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 2945 9019 2951 9038 2974 9034 2964 9005
TIME...MOT...LOC 1914Z 199DEG 6KT 2956 9026
Local storm report, May 30, 3:35 PM CDT, 1 hour 7 minutes before
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The office that day

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

IssuedProductOfficeCountiesLasted
May 29, 7:38 PM CDTSpecial Weather StatementLIXJefferson67 min
May 30, 3:04 AM CDTSpecial Weather StatementLIXJefferson41 min
May 30, 3:39 AM CDTSpecial Marine WarningLIX51 min
May 30, 4:55 AM CDTSpecial Weather StatementLIXPlaquemines35 min
May 30, 8:12 AM CDTSpecial Weather StatementLIXAscension, Livingston33 min
May 30, 8:39 AM CDTSpecial Marine WarningLIX66 min
May 30, 9:28 AM CDTSpecial Weather StatementLIXSaint John the Baptist62 min
May 30, 9:33 AM CDTSpecial Marine WarningLIX57 min
May 30, 10:20 AM CDTSpecial Weather StatementLIXTerrebonne25 min
May 30, 11:52 AM CDTSpecial Weather StatementLIXTerrebonne53 min
May 30, 12:51 PM CDTSpecial Weather StatementLIXLafourche54 min
May 30, 12:53 PM CDTTornado WarningLIXLafourche, Terrebonne24 min
May 30, 1:02 PM CDTAreal Flood AdvisoryLIXAssumption, Lafourche, Saint Charles, Terrebonne3 hr
May 30, 1:28 PM CDTSpecial Weather StatementLIXLafourche32 min
May 30, 1:36 PM CDTSevere Thunderstorm WarningLIXJefferson, Lafourche24 min
May 30, 2:16 PM CDTSpecial Weather StatementLIXJefferson29 min
May 30, 2:18 PM CDTSpecial Marine WarningLIX27 min
May 30, 2:23 PM CDTTornado WarningLIXJefferson, Lafourche17 min
May 30, 3:05 PM CDTSpecial Marine WarningLIX85 min
May 30, 3:15 PM CDTSevere Thunderstorm WarningLIXJefferson, Lafourche30 min
May 30, 3:19 PM CDTSpecial Marine WarningLIX26 min
May 30, 3:26 PM CDTTornado WarningLIXJefferson, Lafourche34 min
May 30, 4:01 PM CDTTornado WarningLIXPlaquemines44 min
May 30, 4:03 PM CDTTornado WarningLIXLafourche27 min
May 30, 4:09 PM CDTSpecial Marine WarningLIX51 min
May 30, 4:27 PM CDTTornado WarningLIXLafourche48 min
May 30, 4:50 PM CDTSpecial Marine WarningLIX85 min
May 30, 5:26 PM CDTSpecial Marine WarningLIX94 min
May 30, 5:39 PM CDTSpecial Marine WarningLIX36 min
May 30, 5:40 PM CDTTornado WarningLIXJefferson23 min
May 30, 6:01 PM CDTSpecial Weather StatementLIXPlaquemines59 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2017Every severe thunderstorm warning in 2017

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.