Alert archive / Louisiana / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 212, NWS Shreveport, LA

May 21, 2011Bienville Parish, Jackson Parish, Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at May 21, 2011, 3:13 PM CDT for Bienville Parish, Jackson Parish, Louisiana. It was in force for 32 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 21, 2011, 3:13 PM CDT (20:13 UTC)
Expired
May 21, 2011, 3:45 PM CDT
In force
32 min
Issued by
NWS Shreveport, LA
Area
Storm-based polygon

Counties Bienville Parish, LA, Jackson Parish, LA

The radar

The Shreveport radar (KSHV), 98 km from the middle of the area, began a volume at 20:14 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 8.2 hours before the alert went out and 90 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, Shreveport, LA at 12:00Z on 2011-05-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1 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, Shreveport, LA at 12:00Z on 2011-05-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 218 square meters per square second.19395878Sfc1 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
1 J/kg
Mixed-layer CIN
-398 J/kg
Mixed-layer LCL
813 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
218 m²/s²
0-3 km storm-relative helicity
238 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 Shreveport, LA wrote its last area forecast discussion before this severe thunderstorm warning went out at May 21, 3:00 PM CDT, 13 minutes earlier.

Area forecast discussion, May 21, 3:00 PM CDT, 13 minutes before
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
300 PM CDT SAT MAY 21 2011

.DISCUSSION...
CLOSED UPPER LOW OVER SD APPARENT ON WV IMAGERY CONTINUES TO
SLOWLY PUSH EWD THIS AFTN. ATTENDANT DISTURBANCE/SHORTWAVE IN THE
BASE OF THE TROF ALSO VISIBLE OVER W TX. DRYLINE IS NOTED JUST TO
THE W OF THE I-35 CORRIDOR...WITH CONVECTION ALREADY INITIATING
ALONG IT. NWD-MOVING OUTFLOW BOUNDARY CONTINUES TO SUSTAIN SCT
TSTMS ACROSS NW LA AS WELL.

DRYLINE IS EXPECTED TO MAKE A PUSH EWD...AS THE SHORTWAVE OVER W
TX ROUNDS THE BASE OF THE TROF. MODELS...WITH THE EXCEPTION OF THE
NAM...INDICATE CONVECTION SHOULD BE ONGOING ACROSS E TX BY 00Z.
WITH 19Z LAPS CAPE SHOWING 2000-2500 J/KG OVER E TX...DEFINITELY
CANNOT RULE OUT SEVERE STORMS FOR THE LATE AFTN AND EVENING.
CONVECTION SHOULD SHIFT N OVERNIGHT ALONG A WARM FRONT...AS THE
DRYLINE RETREATS W...AND A SFC LOW BEGINS TO DEVELOP ACROSS THE
SRN PLAINS. THIS BOUNDARY WILL PROVIDE A FOCUS FOR SHOWERS AND
TSTMS ACROSS THE NRN AND WRN SECTIONS OF THE REGION THROUGH TUE.

UPPER TROF FINALLY EJECTS ON WED...MOVING ACROSS NRN AR BY LATE
WED/EARLY THU. MODELS SUGGEST CONTINUED RAINFALL ACROSS OK/AR IN
THE VC OF THE SFC LOW...AS WELL AS ALONG THE COLD FRONT AS IT MOVES
THROUGH DURING THU.

TEMP-WISE...NO REAL RELIEF FROM WARM AND HUMID CONDITIONS IS
EXPECTED UNTIL THE FRONT MOVES THROUGH DURING THE LATTER PART OF
THE WORK WEEK. /12/

&&

.AVIATION...
WIDELY SCTD CONVECTION ACROSS NRN LA STUBBORNLY HANGS THROUGH THIS
AFTERNOON ALONG AN APPARENT WEAK OUTFLOW BOUNDARY WITH DAYTIME
HEATING.  CURRENT CONVECTIVE TRENDS REMAIN TOO SMALL IN AREAL
COVERAGE TO MENTION TSRA IN 18Z TAFS.  CONDITIONS TO REMAIN VFR
THROUGH SUNDAY MORNING WITH PERHAPS A FEW WIDELY SCATTERED AREAS OF
MVFR CEILINGS IN SEASONALLY MOIST AIRMASS...BUT WILL NOT FORECAST IN
18Z TAFS AS WELL. /VIII/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  72  89  71  88  71 /  30  20  20  20  10
MLU  70  91  70  89  69 /  20  20  10  10  10
DEQ  68  85  68  84  68 /  30  30  30  20  20
TXK  71  87  69  86  69 /  30  30  30  20  20
ELD  69  88  68  87  69 /  30  20  20  20  20
TYR  74  89  72  87  72 /  30  20  20  20  10
GGG  72  89  71  88  71 /  30  20  20  20  10
LFK  72  92  72  91  73 /  30  20  10  10  10

&&

.SHV WATCHES/WARNINGS/ADVISORIES...
AR...NONE.
LA...NONE.
OK...NONE.
TX...NONE.
&&

12/08
Hazardous weather outlook, May 21, 11:45 AM CDT, 3 hours 28 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1145 AM CDT SAT MAY 21 2011

ARZ050-051-059>061-070>073-LAZ001>006-010>012-017-OKZ077-TXZ096-
097-108>112-124>126-136>138-149>153-165>167-221200-
SEVIER-HOWARD-LITTLE RIVER-HEMPSTEAD-NEVADA-MILLER-LAFAYETTE-
COLUMBIA-UNION AR-CADDO-BOSSIER-WEBSTER-CLAIBORNE-LINCOLN-
UNION LA-DE SOTO-RED RIVER-BIENVILLE-SABINE LA-MCCURTAIN-BOWIE-
FRANKLIN-TITUS-CAMP-MORRIS-CASS-WOOD-UPSHUR-MARION-SMITH-GREGG-
HARRISON-CHEROKEE-RUSK-PANOLA-NACOGDOCHES-SHELBY-ANGELINA-
SAN AUGUSTINE-SABINE TX-
1145 AM CDT SAT MAY 21 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTH CENTRAL
ARKANSAS...SOUTHWEST ARKANSAS...NORTH CENTRAL LOUISIANA...
NORTHWEST LOUISIANA...SOUTHEAST OKLAHOMA...EAST TEXAS AND
NORTHEAST TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

SHOWERS AND THUNDERSTORMS WILL BE POSSIBLE AGAIN THIS AFTERNOON AND
EVENING BEGINNING OVER EAST TEXAS AND GRADUALLY WORKING EASTWARD...AND
SOME OF THE STORMS MAY BECOME SEVERE. LARGE HAIL WILL BE THE MAIN
THREAT WITH THESE STORMS...BUT DAMAGING WINDS AND ISOLATED TORNADOES
CANNOT BE RULED OUT.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER THE NEXT
SEVERAL DAYS...AS A LARGE UPPER LEVEL STORM SYSTEM SLOWLY MOVES OUT
OF THE ROCKIES AND INTO THE GREAT PLAINS. ADDITIONAL HEAVY RAINFALL
MAY BRING A GREATER THREAT FOR FLASH FLOODING...ESPECIALLY ACROSS
AREAS OF NORTHEAST TEXAS...SOUTHEAST OKLAHOMA...AND SOUTHWEST
ARKANSAS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON OR TONIGHT.

LAZ013-014-018>022-221200-
JACKSON-OUACHITA-NATCHITOCHES-WINN-GRANT-CALDWELL-LA SALLE-
1145 AM CDT SAT MAY 21 2011

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF NORTH CENTRAL
LOUISIANA AND NORTHWEST LOUISIANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT...

SHOWERS AND THUNDERSTORMS...POTENTIALLY STRONG...MAY DEVELOP AGAIN THIS
EVENING. ALTHOUGH SEVERE WEATHER IS NOT ANTICIPATED...SMALL HAIL
AND GUSTY WINDS WILL BE POSSIBLE WITH ANY STORMS THAT DEVELOP.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY...

ADDITIONAL SHOWERS AND THUNDERSTORMS ARE EXPECTED OVER THE NEXT
SEVERAL DAYS...AS A LARGE UPPER LEVEL STORM SYSTEM SLOWLY MOVES OUT
OF THE ROCKIES AND INTO THE GREAT PLAINS.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION SHOULD NOT BE NEEDED THIS AFTERNOON OR TONIGHT.

12

In the hours before

Special weather statement, May 21, 1:10 PM CDT, 2 hours 3 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
110 PM CDT SAT MAY 21 2011

LAZ001-002-010-211915-
BOSSIER-CADDO-DE SOTO-
110 PM CDT SAT MAY 21 2011

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY...EFFECTIVE UNTIL 215 PM CDT...FOR THE FOLLOWING
PARISHES...

IN NORTHWEST LOUISIANA...
     DE SOTO...CADDO AND BOSSIER...

INCLUDING THE FOLLOWING LOCATIONS...
     BOSSIER CITY...SHREVEPORT AND STONEWALL...

AT 108 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
DETECTING A STRONG THUNDERSTORM 11 MILES SOUTHWEST OF STONEWALL...OR
17 MILES NORTHWEST OF MANSFIELD...MOVING NORTHEAST AT 25 MPH.

SMALL HAIL...AND WINDS 30 TO 40 MPH ARE EXPECTED WITH THIS STORM.

VII
Special weather statement, May 21, 1:28 PM CDT, 1 hour 45 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
128 PM CDT SAT MAY 21 2011

LAZ010-011-017-018-211930-
DE SOTO-NATCHITOCHES-RED RIVER-SABINE-
128 PM CDT SAT MAY 21 2011

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY...EFFECTIVE UNTIL 230 PM CDT...FOR THE FOLLOWING
PARISHES...

IN NORTHWEST LOUISIANA...
     SABINE...RED RIVER...NATCHITOCHES AND DE SOTO...

INCLUDING THE FOLLOWING LOCATIONS...
     COUSHATTA...

AT 125 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
DETECTING A STRONG THUNDERSTORM 11 MILES EAST OF CONVERSE...OR 21
MILES SOUTHEAST OF MANSFIELD...MOVING NORTH NORTHEAST AT 20 MPH.
ANOTHER STRONG THUNDERSTORM WAS LOCATED JUST NORTH OF COUSHATTA.

SMALL HAIL...AND WINDS 30 TO 40 MPH ARE EXPECTED WITH THIS STORM.

VII
Special weather statement, May 21, 2:43 PM CDT, 30 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
243 PM CDT SAT MAY 21 2011

LAZ010>012-017-018-212045-
BIENVILLE-DE SOTO-NATCHITOCHES-RED RIVER-SABINE-
243 PM CDT SAT MAY 21 2011

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY...EFFECTIVE UNTIL 345 PM CDT...FOR THE FOLLOWING
PARISHES...

IN NORTHWEST LOUISIANA...
     SABINE...RED RIVER...NATCHITOCHES...DE SOTO AND BIENVILLE...

INCLUDING THE FOLLOWING LOCATIONS...
     CONVERSE...COUSHATTA AND MANSFIELD...

AT 240 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
DETECTING A STRONG THUNDERSTORM 6 MILES SOUTH OF MANSFIELD...MOVING
NORTHEAST AT 25 MPH.

SMALL HAIL...AND WINDS 30 TO 40 MPH ARE EXPECTED WITH THIS STORM.

VII
Local storm report, May 21, 2:54 PM CDT, 19 minutes before
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Special weather statement, May 21, 3:04 PM CDT, 9 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
304 PM CDT SAT MAY 21 2011

LAZ005-011>013-018-212100-
BIENVILLE-JACKSON-LINCOLN-NATCHITOCHES-RED RIVER-
304 PM CDT SAT MAY 21 2011

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY...EFFECTIVE UNTIL 400 PM CDT...FOR THE FOLLOWING
PARISHES...

IN NORTHWEST LOUISIANA...
     RED RIVER...NATCHITOCHES AND BIENVILLE...
IN NORTH CENTRAL LOUISIANA...
     LINCOLN AND JACKSON...

INCLUDING THE FOLLOWING LOCATIONS...
     GRAMBLING...

AT 257 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
DETECTING A STRONG THUNDERSTORM 12 MILES NORTHEAST OF COUSHATTA...OR
26 MILES NORTH OF NATCHITOCHES...MOVING NORTHEAST AT 25 MPH.

DIME SIZE HAIL...AND WINDS AROUND 40 MPH ARE EXPECTED WITH THIS
STORM.

VIII.
Local storm report, May 21, 3:07 PM CDT, 6 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
307 PM CDT SAT MAY 21 2011

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

0300 PM     HAIL             3 SW BELCHER            32.72N 93.87W
05/21/2011  E0.50 INCH       CADDO              LA   TRAINED SPOTTER

            PEA TO MARBLE SIZE HAIL REPORTED.

&&

20

The office that day

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

IssuedProductOfficeCountiesLasted
May 20, 7:33 PM CDTSevere Thunderstorm WarningSHVHarrison, Marion27 min
May 20, 7:40 PM CDTSevere Thunderstorm WarningSHVBowie, Cass35 min
May 20, 8:06 PM CDTSevere Thunderstorm WarningSHVBowie39 min
May 20, 8:32 PM CDTSevere Thunderstorm WarningSHVBowie, Cass43 min
May 20, 8:52 PM CDTAreal Flood AdvisorySHVCherokee3 hr
May 20, 9:28 PM CDTAreal Flood AdvisorySHVBowie3 hr
May 20, 11:42 PM CDTRiver Flood WarningSHVFranklin, Morris, Red River, Titus3 days
May 21, 6:15 AM CDTSevere Thunderstorm WarningSHVAngelina, Nacogdoches, San Augustine45 min
May 21, 6:32 PM CDTSevere Thunderstorm WarningSHVColumbia, Union43 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2011Every severe thunderstorm warning in 2011

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; radar from the NEXRAD Level II archive.