Alert archive / Mississippi / Severe Thunderstorm Warnings in 2015

Severe Thunderstorm Warning 141, NWS New Orleans, LA

September 5, 2015Saint Tammany Parish, Louisiana; Hancock County, Pearl River County, Mississippi

NWS New Orleans, LA issued this severe thunderstorm warning at Sep 5, 2015, 6:41 PM CDT for Saint Tammany Parish, Louisiana; Hancock County, Pearl River County, Mississippi. It was in force for 64 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: Sep 5, 2015, 6:41 PM CDT (23:41 UTC)
Expired: Sep 5, 2015, 7:45 PM CDT
In force: 64 min
Issued by: NWS New Orleans, LA
Area: Storm-based polygon

Counties Saint Tammany Parish, LA, Hancock County, MS, Pearl River County, MS

The nearest sounding before it

Slidell Radar S, LA (KSIL), launched 12:00Z, 11.7 hours before the alert went out and 31 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: 2020 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 760 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 10 m²/s²
0-3 km storm-relative helicity: -7 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 Sep 5, 3:07 PM CDT, 3 hours 34 minutes earlier.

Area forecast discussion, Sep 5, 3:07 PM CDT, 3 hours 34 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW ORLEANS LA
307 PM CDT SAT SEP 5 2015

.SHORT TERM...
AIR MASS THUNDERSTORMS HAVE DEVELOPED DUE TO DIFFERENTIAL HEATING
THIS AFTERNOON. THEY ARE MOVING SLOWLY SOUTH AROUND THE EAST SIDE
OF THE UPPER LEVEL RIDGE CENTERED IN EASTERN TEXAS.

.LONG TERM...
THE UPPER LEVEL RIDGE WILL RETROGRADE TO THE WEST AS A WEAK CUT
OFF UPPER LEVEL LOW DEVELOPS OVER THE SOUTHEAST U.S. THIS UPPER
LEVEL LOW WILL MIGRATE SLOWLY SOUTHWEST THROUGH THE LABOR DAY
WEEKEND. AS THE UPPER LEVEL LOW MOVES WEST OF THE FORECAST AREA BY
MID WEEK THERE WILL BE AN INCREASING CHANCE OF SHOWERS AND
THUNDERSTORMS ACROSS THE REGION. THE UPPER LEVEL LOW WILL WEAKEN
TOWARDS THE END OF THE WEEK AS A STRONGER UPPER LEVEL TROUGH AND
COLD FRONT APPROACHES THE LOWER MISSISSIPPI VALLEY BY FRIDAY.

BASED ON THE ABOVE REASONING I HAVE MODIFIED OUR CHANCE OF RAIN TO
BRING IT MORE IN LINE WITH OUR NEIGHBORING FORECAST OFFICES...BUT
STILL NOT AS HIGH AS SOME OF THE ENSEMBLE MODELS ARE INDICATING.
IT HAS BEEN OUR EXPERIENCE THAT THE ENSEMBLES TEND TO OVER
FORECAST THE CHANCE OF SUMMER TIME CONVECTION.

&&

.AVIATION...
VFR CONDITIONS WILL PRIMARILY PREVAIL AT THE TAF SITES THROUGH
THE TAF FORECAST PERIOD OUTSIDE OF ANY CONVECTION THAT MAY IMPACT
THE TERMINALS...PRIMARILY DURING THE AFTERNOON HOURS. PATCHY FOG
AND STRATUS DEVELOPMENT LATE TONIGHT AND EARLY SUNDAY MORNING MAY BE
OBSERVED AT KMCB AND KHUM RESULTING IN A PERIOD OF MVFR TO IFR
CONDITIONS. 11

&&

.MARINE...
A WEAK PRESSURE GRADIENT ACROSS THE NORTHERN GULF OF MEXICO DURING
THE PERIOD WILL RESULT IN A CONTINUATION OF GENERALLY LIGHT AND A
TIMES VARIABLE WINDS ACROSS THE COASTAL WATERS. WINDS WILL MAINLY BE
LESS THAN 10 KNOTS AND SEAS 2 FEET OR LESS THROUGH MID WEEK.
SCATTERED CONVECTION WILL BE POSSIBLE EACH DAY. 11

&&

.DECISION SUPPORT...
DSS CODE....GREEN.
DEPLOYED...NONE.
ACTIVATION...NONE.
ACTIVITIES...NONE.

DECISION SUPPORT SERVICES (DSS) CODE LEGEND
GREEN  = NO WEATHER IMPACTS THAT REQUIRE ACTION
BLUE   = LONG FUSED WATCH/WARNING/ADVISORY IN EFFECT OR HIGH
         VISIBILITY EVENT
YELLOW = HEIGHTENED IMPACTS WITH SHORT FUSED WATCH/WARNING/ADVISORY
         ISSUANCES; RADAR SUPPORT
ORANGE = HIGH IMPACTS - SLIGHT TO MODERATE RISK SEVERE; NEARBY
         TROPICAL EVENTS; HAZMAT OR OTHER LARGE EPISODES
RED    = FULL ENGAGEMENT FOR MODERATE RISK SVR AND/OR DIRECT
         TROPICAL THREATS; EVENTS OF NATIONAL SIGNIFICANCE

&&

.PRELIMINARY POINT TEMPS/POPS...
MCB  74  92  71  90 /  30  40  20  30
BTR  75  93  72  91 /  20  40  20  30
ASD  76  90  74  88 /  30  40  20  30
MSY  78  90  77  88 /  20  40  20  30
GPT  76  88  75  87 /  20  40  20  30
PQL  76  89  74  88 /  20  40  20  30

&&

.LIX WATCHES/WARNINGS/ADVISORIES...
LA...NONE.
GM...NONE.
MS...NONE.
GM...NONE.
&&

Hazardous weather outlook, Sep 5, 6:01 PM CDT, 40 minutes before

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In the hours before

Special weather statement, Sep 5, 3:40 PM CDT, 3 hours 1 minute before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
340 PM CDT SAT SEP 5 2015

MSZ082-052115-
JACKSON-
340 PM CDT SAT SEP 5 2015

...A STRONG THUNDERSTORM WILL AFFECT EASTERN JACKSON COUNTY...

AT 340 PM CDT...A STRONG THUNDERSTORM WAS OVER BIG POINT...OR 8 MILES
NORTH OF ESCATAWPA...MOVING SOUTH AT 25 MPH.

WINDS IN EXCESS OF 40 MPH ARE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
OCEAN SPRINGS...MOSS POINT...ESCATAWPA...GAUTIER...WADE...GULF PARK
ESTATES...BIG POINT...VANCLEAVE...HICKORY HILLS...HURLEY AND HELENA.

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 3032 8849 3032 8851 3035 8851 3034 8852
      3035 8858 3037 8859 3037 8860 3036 8860
      3035 8861 3037 8861 3036 8862 3037 8862
      3034 8870 3035 8874 3037 8878 3071 8858
      3066 8841 3060 8840
TIME...MOT...LOC 2040Z 020DEG 22KT 3062 8852

11

Special weather statement, Sep 5, 4:15 PM CDT, 2 hours 26 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
415 PM CDT SAT SEP 5 2015

MSZ081-082-052215-
JACKSON-HARRISON-
415 PM CDT SAT SEP 5 2015

...A STRONG THUNDERSTORM WILL AFFECT EASTERN HARRISON AND SOUTHERN
JACKSON COUNTIES...

AT 414 PM CDT...A STRONG THUNDERSTORM WAS OVER OCEAN SPRINGS...MOVING
WEST AT 20 MPH.

WINDS IN EXCESS OF 40 MPH ARE POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
GULFPORT...BILOXI...OCEAN SPRINGS...LONG BEACH...MOSS POINT...ST.
MARTIN...ESCATAWPA...GAUTIER...D'IBERVILLE...GULF HILLS...BIG
POINT...HELENA...LATIMER...GULF PARK ESTATES...LYMAN...VANCLEAVE...
HICKORY HILLS...SAUCIER AND GULFPORT AIRPORT.

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 3032 8850 3035 8851 3035 8858 3037 8859
      3034 8870 3037 8882 3036 8882 3038 8884
      3038 8877 3043 8885 3043 8899 3042 8901
      3040 8886 3035 8914 3061 8914 3059 8846
      3034 8844
TIME...MOT...LOC 2114Z 071DEG 17KT 3040 8878

CAB

Special weather statement, Sep 5, 4:44 PM CDT, 1 hour 57 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE NEW ORLEANS LA
444 PM CDT SAT SEP 5 2015

LAZ066-052230-
LOWER TERREBONNE LA-
444 PM CDT SAT SEP 5 2015

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL TERREBONNE PARISH
UNTIL 530 PM CDT...

AT 444 PM CDT...DOPPLER RADAR WAS TRACKING A STRONG THUNDERSTORM NEAR
COCODRIE...OR 23 MILES SOUTH OF HOUMA...MOVING SOUTHEAST AT 15 MPH.

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

LOCATIONS IMPACTED INCLUDE...
COCODRIE...DULAC...TAMBOUR BAY BUOY AND LUMCON CENTER BUOY.

LAT...LON 2911 9079 2910 9080 2926 9087 2934 9069
      2921 9059 2923 9061 2919 9061 2925 9063
      2919 9064 2918 9061 2914 9068 2912 9068
      2910 9077
TIME...MOT...LOC 2144Z 334DEG 14KT 2924 9075

Special weather statement, Sep 5, 6:27 PM CDT, 14 minutes before

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Local storm report, Sep 5, 6:37 PM CDT, 4 minutes before

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Local storm report, Sep 5, 6:38 PM CDT, 3 minutes before

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The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 5, 2:56 PM CDT	Special Marine Warning	LIX		49 min
Sep 5, 4:44 PM CDT	Special Weather Statement	LIX	Terrebonne	46 min
Sep 5, 6:27 PM CDT	Special Weather Statement	LIX	Saint Tammany	93 min
Sep 5, 6:59 PM CDT	Special Weather Statement	LIX	Saint Tammany	46 min
Sep 5, 2:52 PM CDT	Special Weather Statement	LIX	Jackson	38 min
Sep 5, 3:40 PM CDT	Special Weather Statement	LIX	Jackson	35 min
Sep 5, 4:15 PM CDT	Special Weather Statement	LIX	Harrison, Jackson	60 min
Sep 5, 5:11 PM CDT	Severe Thunderstorm Warning	LIX	Harrison	49 min
Sep 5, 5:54 PM CDT	Severe Thunderstorm Warning	LIX	Hancock, Harrison	66 min

Nearby

Severe Thunderstorm Warnings in Mississippi, 2015 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.