Alert archive / Louisiana / Severe Thunderstorm Warnings in 2007

Severe Thunderstorm Warning 290, NWS Shreveport, LA

November 21, 2007Sabine Parish, Louisiana

NWS Shreveport, LA issued this severe thunderstorm warning at Nov 21, 2007, 3:25 PM CST for Sabine Parish, Louisiana. It was in force for 65 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: Nov 21, 2007, 3:25 PM CST (21:25 UTC)
Expired: Nov 21, 2007, 4:30 PM CST
In force: 65 min
Issued by: NWS Shreveport, LA
Area: Storm-based polygon

County Sabine Parish, LA

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

Issued	Product	Office	Lasted
Nov 21, 2:29 PM CST	Severe Thunderstorm Watch	SPC	8 hr

The nearest sounding before it

Shreveport, LA (KSHV), launched 12:00Z, 9.4 hours before the alert went out and 104 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: 642 J/kg
Mixed-layer CIN: -45 J/kg
Mixed-layer LCL: 615 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 143 m²/s²
0-3 km storm-relative helicity: 171 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

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 Nov 21, 11:11 AM CST, 4 hours 14 minutes earlier.

Area forecast discussion, Nov 21, 11:11 AM CST, 4 hours 14 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
1111 AM CST WED NOV 21 2007

.DISCUSSION...
COLD FRONT IS JUST ENTERING THE NORTHWEST PART OF OUR FORECAST
AREA LATE THIS MORNING. ALONG AND JUST AHEAD OF THIS FRONT THE
ATMOSPHERE HAS ENOUGH LOW LEVEL MOISTURE...MODERATE INSTABILITY
WITH CAPES ABOUT 1600...LI/S ABOUT -5...AND LOW LEVEL WIND
SHEAR...TO CREATE THE POSSIBILITY OF SCATTERED SEVERE
THUNDERSTORMS DURING THE AFTERNOON AND EVENING HOURS. THE STORMS
WILL BE ACROSS THE NORTHWEST HALF OF THE FORECAST AREA THIS
AFTERNOON. THE FRONT SHOULD MOVE BY 00Z TO A LINE FROM
ELD...SHV...TO LFK. SCATTERED SEVERE THUNDERSTORMS WILL BE
POSSIBLE ALONG AND AHEAD OF THE FRONT IN NORTH CENTRAL LA THIS
EVENING. THE MAIN THREAT IS LARGE HAIL AND DAMAGING WIND...BUT AN
ISOLATED TORNADO CANNOT BE RULED OUT. WILL UPDATE THE ZONES TO
INCLUDE THE MENTION OF SEVERE THUNDERSTORMS DURING THE AFTERNOON
AND EVENING HOURS OVER PARTS OF THE FOUR STATE AREA...AND TO
ADJUST THE POPS A LITTLE TO REFLECT CURRENT TIMING OF THE FRONT.
NO OTHER CHANGES TO THE FORECAST ARE NEEDED AT THIS TIME.

&&

.AVIATION...
COLD FRONT EXTENDS FROM NEAR FSM...TO HUGO OK...TO JUST W OF
GVT...TO INJ AS OF 16Z...AND WILL TRANSLATE QUICKLY SE INTO THE
REGION THIS AFTERNOON...REACHING A TXK...TO GGG...TO DKR LINE
AROUND 21Z...AND AN ELD...TO SHV...TO LFK LINE BY 00Z. BKN MVFR
CIGS /FL015-020/ WILL CONTINUE TO SLOWLY LIFT...BECOMING VFR
AROUND MIDDAY WITH CONTINUED HEATING. HOWEVER...SCATTERED
CONVECTION WILL CONTINUE TO FIRE ALONG/JUST AHEAD OF THE FRONT
THIS AFTERNOON...WITH OTHER WIDELY SCATTERED DEVELOPMENT POSSIBLE
ELSEWHERE IN POCKETS OF CLEARING/ENHANCED HEATING AND INSTABILITY.
WILL LIKELY TEMPO IN THUNDER FOR A FEW HOURS THIS AFTERNOON FOR
ALL TERMINALS WITH THE FROPA...WITH WINDS QUICKLY VEERING NNW
15-20KTS WITH GUSTS TO 25KTS POSSIBLE THIS EVENING...PERHAPS
TAPERING A BIT OVERNIGHT. POST FRONTAL STRATOCU /FL015/ WILL
LIKELY SPILL S BEHIND THE FRONT...SCATTERING OUT FROM N TO S
BETWEEN 12-18Z THURSDAY. N WINDS OF 10-15KTS CAN BE EXPECTED
THROUGH THE DAY THURSDAY...WITH GUSTS TO 20KTS POSSIBLE...TAPERING
OFF BY 00Z FRIDAY. IN ADDITION...THIN CIRRUS SHIELD WILL QUICKLY
TRAVERSE E ACROSS THE AREA THURSDAY...WITH THESE HIGH BASED CIGS
LOWERING TO AROUND 12KFT AFTER 00Z FRIDAY. /15/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  79  43  56  38 /  50  50  10  10
MLU  79  43  54  38 /  50  70  10  10
DEQ  73  35  54  32 /  40  30  10  10
TXK  74  39  55  35 /  70  40  10  10
ELD  78  40  54  33 /  70  60  10  10
TYR  74  38  52  37 /  40  30  10  20
GGG  77  38  52  36 /  40  40  10  10
LFK  81  43  58  40 /  40  50  10  20

&&

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

03/15

Hazardous weather outlook, Nov 21, 11:40 AM CST, 3 hours 45 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1140 AM CST WED NOV 21 2007

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-TXZ096-
097-108>112-124>126-136>138-149>153-165>167-221200-
ANGELINA-BIENVILLE-BOSSIER-BOWIE-CADDO-CALDWELL-CAMP-CASS-CHEROKEE-
CLAIBORNE-COLUMBIA-DE SOTO-FRANKLIN-GRANT-GREGG-HARRISON-HEMPSTEAD-
HOWARD-JACKSON-LA SALLE-LAFAYETTE-LINCOLN-LITTLE RIVER-MARION-
MCCURTAIN-MILLER-MORRIS-NACOGDOCHES-NATCHITOCHES-NEVADA-OUACHITA-
PANOLA-RED RIVER LA-RED RIVER TX-RUSK-SABINE LA-SABINE TX-
SAN AUGUSTINE-SEVIER-SHELBY-SMITH-TITUS-UNION AR-UNION LA-UPSHUR-
WEBSTER-WINN-WOOD-
1140 AM CST WED NOV 21 2007

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

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

A COLD FRONT WILL MOVE ACROSS THE FOUR STATE AREA THIS AFTERNOON
AND EVENING. AS THE FRONT MOVES INTO A RATHER UNSTABLE ATMOSPHERE...
IT WILL BE ACCOMPANIED BY SCATTERED THUNDERSTORMS...SOME OF WHICH MAY
BECOME SEVERE. THE MAIN THREATS FROM THE THUNDERSTORMS THIS AFTERNOON
AND EVENING ARE LARGE HAIL AND BRIEF DAMAGING WINDS...BUT AN ISOLATED
TORNADO COULD ALSO OCCUR. THE CONVECTION WILL START ACROSS NORTHEAST
TEXAS...AND SOUTHWEST ARKANSAS EARLY IN THE AFTERNOON...AND MOVE
SOUTHEAST INTO SOUTH CENTRAL ARKANSAS...AND NORTH LOUISIANA...BY LATE
AFTERNOON. THE SCATTERED STORMS WILL CONTINUE INTO NORTH CENTRAL
LOUISIANA DURING THE EVENING.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER INFORMATION STATEMENT...

ACTIVATION OF SKYWARN SPOTTERS...HAM RADIO OPERATORS...AND EMERGENCY
MANAGEMENT...IN SUPPORT OF SEVERE WEATHER OPERATIONS MAY BE REQUIRED
THIS AFTERNOON AND EVENING.

03

In the hours before

Local storm report, Nov 21, 2:05 PM CST, 1 hour 20 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
205 PM CST WED NOV 21 2007

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

0202 PM     HAIL             NACOGDOCHES             31.61N 94.65W
11/21/2007  M0.75 INCH       NACOGDOCHES        TX   TRAINED SPOTTER

            NUMEROUS REPORTS CITY WIDE.

&&

ASTEVENS

Local storm report, Nov 21, 2:22 PM CST, 1 hour 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
222 PM CST WED NOV 21 2007

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

0210 PM     HAIL             NACOGDOCHES             31.61N 94.65W
11/21/2007  E1.00 INCH       NACOGDOCHES        TX   TRAINED SPOTTER

            HAIL FELL FOR ABOUT 7 MINUTES.

&&

ASTEVENS

Local storm report, Nov 21, 3:24 PM CST, 1 minute before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
324 PM CST WED NOV 21 2007

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

0305 PM     HAIL             SAN AUGUSTINE           31.53N 94.11W
11/21/2007  E0.75 INCH       SAN AUGUSTINE      TX   LAW ENFORCEMENT

            HAIL FELL FOR ABOUT THREE MINUTES IN TOWN.

&&

13

The office that day

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

Issued	Product	Office	Counties	Lasted
Nov 21, 1:54 PM CST	Severe Thunderstorm Warning	SHV	Nacogdoches	66 min
Nov 21, 2:38 PM CST	Severe Thunderstorm Warning	SHV	San Augustine	52 min
Nov 21, 3:09 PM CST	Severe Thunderstorm Warning	SHV	Harrison	66 min
Nov 21, 3:14 PM CST	Severe Thunderstorm Warning	SHV	Sabine	61 min
Nov 21, 3:43 PM CST	Severe Thunderstorm Warning	SHV	Panola, Rusk	53 min
Nov 21, 4:07 PM CST	Lake Wind Advisory	SHV	Angelina, Bowie, Camp, Cass, Cherokee, Franklin and 15 more	12 hr
Nov 21, 3:39 PM CST	Severe Thunderstorm Warning	SHV	Caddo	66 min
Nov 21, 4:04 PM CST	Severe Thunderstorm Warning	SHV	Natchitoches	56 min
Nov 21, 4:50 PM CST	Severe Thunderstorm Warning	SHV	Claiborne, Webster	55 min
Nov 21, 5:10 PM CST	Severe Thunderstorm Warning	SHV	Grant	65 min
Nov 21, 5:29 PM CST	Severe Thunderstorm Warning	SHV	Claiborne, Lincoln, Union	31 min
Nov 21, 1:59 PM CST	Severe Thunderstorm Warning	SHV	Hempstead, Howard, Little River, Sevier	61 min
Nov 21, 3:00 PM CST	Severe Thunderstorm Warning	SHV	Hempstead	30 min
Nov 21, 3:06 PM CST	Severe Thunderstorm Warning	SHV	Columbia, Lafayette, Nevada	54 min
Nov 21, 3:36 PM CST	Severe Thunderstorm Warning	SHV	Lafayette	24 min
Nov 21, 3:53 PM CST	Severe Thunderstorm Warning	SHV	Columbia	67 min

Nearby

Severe Thunderstorm Warnings in Louisiana, 2007 Every severe thunderstorm warning in 2007

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.