Severe Thunderstorm Warning 407, NWS Shreveport, LA

574 
WWUS54 KSHV 230624
SVSSHV

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
124 AM CDT SUN OCT 23 2011

ARC091-TXC037-063-067-159-203-315-343-449-459-499-230700-
/O.CON.KSHV.SV.W.0407.000000T0000Z-111023T0700Z/
MILLER AR-FRANKLIN TX-HARRISON TX-MARION TX-MORRIS TX-TITUS TX-
UPSHUR TX-WOOD TX-CASS TX-CAMP TX-BOWIE TX-
124 AM CDT SUN OCT 23 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 200 AM CDT
FOR BOWIE...CAMP...CASS...WOOD...UPSHUR...TITUS...MORRIS...MARION...
HARRISON...FRANKLIN AND MILLER COUNTIES...

AT 117 AM CDT...A LINE OF SEVERE THUNDERSTORMS WAS REPORTED CAPABLE
OF PRODUCING QUARTER SIZE HAIL...AND DESTRUCTIVE WINDS IN EXCESS OF
70 MPH.  THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM WAKE
VILLAGE TO HUGHES SPRINGS TO PERRYVILLE...OR ALONG A LINE EXTENDING
FROM WAKE VILLAGE TO 21 MILES SOUTH OF SIMMS TO 7 MILES SOUTHEAST OF
WINNSBORO...MOVING SOUTHEAST AT 40 MPH.

OTHER LOCATIONS IN THE WARNING INCLUDE BUT ARE NOT LIMITED TO 
TEXARKANA...LINDEN...QUEEN 
CITY...AVINGER...ATLANTA...GILMER...FOUKE...AND HARLETON.   

PRECAUTIONARY/PREPAREDNESS ACTIONS...

IN ADDITION TO LARGE HAIL AND DAMAGING WINDS...CONTINUOUS CLOUD TO
GROUND LIGHTNING IS OCCURRING WITH THIS STORM. MOVE INDOORS
IMMEDIATELY! LIGHTNING IS ONE OF NATURES NUMBER ONE KILLERS.
REMEMBER...IF YOU CAN HEAR THUNDER...YOU ARE CLOSE ENOUGH TO BE
STRUCK BY LIGHTNING.

&&

LAT...LON 3295 9557 3297 9532 3304 9531 3321 9486
      3356 9418 3340 9371 3339 9370 3306 9387
      3302 9392 3302 9404 3290 9404 3276 9418
      3258 9455 3258 9470 3265 9470 3266 9475
      3258 9484 3258 9510
TIME...MOT...LOC 0621Z 313DEG 27KT 3335 9412 3303 9457
          3284 9521

$$

VII

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE SHREVEPORT LA
1207 AM CDT SUN OCT 23 2011

.UPDATE...
ZONE UPDATE JUST SENT TO CANCEL SVR WATCH 869 FOR NE TX/SE
OK/EXTREME SW AR. ONGOING MCS OVER NNE TX/SE OK/ADJACENT SW AR
CONTINUES TO MAKES STEADY PROGRESS SE TONIGHT...BUT HAVE SHOWN A
WEAKENING TREND AS IT TRACKS INTO A MORE STABLE AND SLIGHTLY DRIER
ENVIRONMENT FARTHER S. 30KT SSW LLJ OVER NCNTRL TX ATOP THE COLD
POOL SURGING S WILL HELP SUSTAIN THIS CONVECTION OVERNIGHT...ESPECIALLY
AS THE PRIMARY SHORTWAVE OVER SRN OK HELPING TO FORCE THIS
CONVECTION CONTINUES TO TRACK SE ACROSS THE REGION OVERNIGHT.
CAN/T RULE OUT LOCALLY STRONGER WIND GUSTS ALSO THE COLD POOL AS
IT ENTERS NE TX...WHILE STEEP LAPSE RATES MAY ALSO ADD A MARGINAL
HAIL THREAT AS WELL. BUT OVERALL...THE SVR THREAT SHOULD BE ISOLATED
OVER OUR REGION OVERNIGHT.

ALSO EXPANDED CATEGORICAL/LIKELY POPS FARTHER S ACROSS E TX AHEAD
OF THE MCS. NO OTHER CHANGES NEEDED TO THE FORECAST ATTM.

15

&&

.PREV DISCUSSION... /ISSUED 949 PM CDT SAT OCT 22 2011/

DISCUSSION...
MCS CONTINUES TO MAKE STEADY PROGRESS SE ACROSS SCNTRL/SE OK
ATTM...ALTHOUGH MUCH OF THE CONVECTION HAS REMAINED N OF A WEAK WARM
FRONT/INVERTED SFC TROUGH...WHICH EXTENDED ACROSS SCNTRL AND SE OK A COUPLE
OF COUNTIES N OF THE RED RIVER. HOWEVER...THE WRN EDGE OF THE
CONVECTION REMAINS MOST INTENSE NNE OF ADM TO ATOKA...WHERE THE BEST
SFC BASED INSTABILITY AND MOISTURE CONVERGENCE LIE. THIS CONVECTION
HAS PRODUCED A SSEWD PROPAGATING COLD POOL...WHICH WILL CROSS THE RED
RIVER INTO FAR NCNTRL/NE TX AFTER 0330Z. SFC MESOANALYSIS INDICATES
THAT THE AIR MASS IS MUCH MORE STABLE ACROSS N/NE TX THIS
EVENING...WITH WEAK CAPPING NOTED ON THE 00Z FWD RAOB. HOWEVER...VERY
STEEP MID LEVEL LAPSE RATES AND COLDER MID LEVEL TEMPS ALOFT NOTED ON
THE REGIONAL RAOBS UPSTREAM ACROSS OK HAVE RESULTED IN A NUMBER OF SVR
HAIL REPORTS ACROSS CNTRL/NE OK N OF THE FRONT...WITH THE HAIL THREAT
PERSISTING FOR A FEW MORE HOURS AS THESE STORMS MOVE ACROSS THE RED
RIVER. DESPITE A MORE STABLE SFC BASED AIR MASS FARTHER S...A 25-30KT
SWRLY LLJ SHOULD MAINTAIN ORGANIZED CONVECTION ALONG THE COLD
POOL...ESPECIALLY AS STRONG FORCING ALOFT BEGINS TO OVERSPREAD THE
AREA LATE WITH THE APPROACH OF A SHARP SHORTWAVE TROUGH NOTED ON THE
WATER VAPOR LOOP OVER CNTRL OK.

DID MAKE SOME MINOR CHANGES TO THE GOING POPS TONIGHT...MAINLY TO
INCREASE THEM TO CATEGORICAL NW OF I-30 THIS EVENING...AND ACROSS THE
REMAINDER OF SW AR AFTER 06Z. ALSO TONED DOWN POPS OVERNIGHT FOR DEEP
E TX/SRN SECTIONS OF NCNTRL LA...AS THE LATER ONSET OF THE CONVECTION
/LATER THAN THE 18Z MODEL RUNS/ WILL RESULT IN A LATER TIMING ACROSS
THESE AREAS...MAINLY AFTER 12Z SUNDAY. AN ISOLATED SVR THREAT MAY
CARRY OVER AFTER 06Z ACROSS NE TX/SE OK/SW AR...BUT THIS THREAT
SHOULD DIMINISH OVERNIGHT AS THE BEST FORCING WILL PROCEED NE OF THE
ONGOING SVR CONVECTION...WHERE THE BEST CONVERGENCE/INSTABILITY LIE.
BUT WILL LET THE SVR WATCH 869 RIDE THROUGH 05Z...AND CONTINUE TO
MONITOR RADAR TRENDS TO SEE IF ANY LOCAL EXTENTION IS NECESSARY. ALSO
RAISED POPS SUNDAY MORNING ACROSS E TX/N LA...WITH THE WEAKENED
CONVECTION EXPECTED TO PERSIST THROUGH MIDMORNING BEFORE DIMINISHING
FROM NW TO SE. VERY LITTLE IF ANY CHANGES WERE NEEDED TO THE ONGOING
FORECAST MIN TEMPS TONIGHT.

ZONE UPDATE ALREADY OUT...GRIDS WILL BE AVAILABLE SHORTLY.

15

AVIATION...
A SHORT WAVE IN NW FLOW ALOFT...BRINGING INCREASING TSTM DEVELOPMENT
THIS EVE ACROSS MUCH OF EASTERN OK. MOST OF THE CONVECTION HAS
REMAINED ON THE NORTH SIDE OF A WEAK EAST TO WEST FRONTAL BOUNDARY.
VERY UNSTABLE AIR ON THE COOL SIDE OF BOUNDARY...AS SEEN ON OKC 0Z
SOUNDING...HAS BEEN YIELDING SVRL HAILSTORMS. LACK OF DEVELOPMENT ON
SOUTH SIDE OF BOUNDARY SUGGESTS SVRL HOURS BEFORE STORMS REACH
AIRPORT TERMINALS IN CWA...WITH POSSIBLE EXCEPTION OF TXK...BEFORE
06Z. FAIRLY LIGHT LOW LVL SOUTHERLY FLOW...AND LACK OF
FROPA...SUGGEST CIGS TO REMAIN MOSTLY VFR THRU PERIOD...OUTSIDE OF
PSBL CONVECTION. FOG MAY DEVELOP ACROSS MOSTLY MLU AND ELD
TERMINALS...WHERE LIGHT WINDS AND LIMITED CLOUDS MAY ALLOW FOR TEMPS
TO FALL THRU DEWPOINTS. AT OTHER LOCATIONS...RAINFALL MAY BE NEEDED FOR
FOG TO DEVELOP LATER TONIGHT. /VII/

&&

.PRELIMINARY POINT TEMPS/POPS...
SHV  60  78  55  82  62 /  70  40  10   0   0
MLU  54  74  51  79  59 /  50  50  10   0   0
DEQ  57  73  48  80  59 /  80  20  10   0   0
TXK  58  72  52  81  62 /  80  30  10   0   0
ELD  54  72  46  79  60 /  80  50  10   0   0
TYR  62  81  57  83  64 /  70  20  10   0   0
GGG  60  80  57  83  62 /  70  30  10   0   0
LFK  60  83  57  85  62 /  40  30  10   0   0

&&

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

15

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1200 PM CDT SAT OCT 22 2011

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-TXZ096-
097-108>112-124>126-136>138-149>153-165>167-231100-
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-
1200 PM CDT SAT OCT 22 2011

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

.DAY ONE...TODAY AND TONIGHT...

ABUNDANT GULF MOISTURE WILL BE MOVING NORTH FROM THE GULF OF MEXICO
INTO A WARM FRONT NEAR THE RED RIVER...AS AN UPPER LEVEL DISTURBANCE
MOVES SOUTHEAST ACROSS THE AREA. THIS WILL RESULT IN SCATTERED TO
NUMEROUS THUNDERSTORMS...SOME OF WHICH MAY BECOME SEVERE. LARGE HAIL
AND DAMAGING WINDS ARE POSSIBLE...ALONG WITH DEADLY LIGHTNING.
AREAS ALONG AND NORTH OF INTERSTATE 20 WILL HAVE THE BEST CHANCE FOR
THUNDERSTORMS AND SEVERE WEATHER.

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

THUNDERSTORMS WILL SPREAD SOUTHEAST ACROSS THE AREA DURING THE DAY
SUNDAY...AND END BY LATE AFTERNOON OR EARLY EVENING. INSTABILITY IS
EXPECTED TO BE WEAK. HOWEVER...HIGH LAPSE RATES ALONG WITH GULF
MOISTURE...AND VEERING WIND UNDER THE NORTHWEST FLOW PATTERN
ALOFT...WILL PRODUCE ISOLATED SEVERE THUNDERSTORMS.

ANOTHER AND MORE AMPLIFIED UPPER TROUGH WILL SEND A STRONGER COLD
FRONT INTO THE FOUR STATE REGION LATE IN THE WEEK.

.SPOTTER INFORMATION STATEMENT...

THE ACTIVATION OF EMERGENCY MANAGEMENT PERSONNEL...HAM RADIO
OPERATORS...AND STORM SPOTTERS MAY BE REQUIRED LATE THIS
AFTERNOON AND OVERNIGHT.

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
1057 PM CDT SAT OCT 22 2011

ARZ050-059-OKZ077-TXZ096-230500-
LITTLE RIVER-MCCURTAIN-RED RIVER-SEVIER-
1057 PM CDT SAT OCT 22 2011

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY...EFFECTIVE UNTIL MIDNIGHT CDT...FOR THE FOLLOWING
COUNTIES...

IN SOUTHWEST ARKANSAS...
     LITTLE RIVER AND SEVIER...
IN SOUTHEAST OKLAHOMA...
     MCCURTAIN...
IN NORTHEAST TEXAS...
     RED RIVER...

INCLUDING THE FOLLOWING LOCATIONS...
     ARKINDA...DE QUEEN...FOREMAN...HORATIO...WINTHROP...BROKEN
     BOW...IDABEL...BAGWELL...BOXELDER...CLARKSVILLE AND
     MANCHESTER...

AT 1057 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
DETECTING STRONG THUNDERSTORMS ALONG A LINE EXTENDING FROM 9 MILES
EAST OF NASHOBA TO 6 MILES SOUTH OF OLETA TO GOODLAND...OR ALONG A
LINE EXTENDING FROM 19 MILES SOUTHEAST OF CLAYTON TO 14 MILES
NORTHEAST OF HUGO TO HUGO...MOVING SOUTHEAST AT 50 MPH.

PEA SIZE HAIL...AND WINDS 40 TO 45 MPH ARE EXPECTED WITH THESE
STORMS.

15

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE SHREVEPORT LA
1204 AM CDT SUN OCT 23 2011

ARZ050-051-059-OKZ077-TXZ096-097-230600-
BOWIE-HOWARD-LITTLE RIVER-MCCURTAIN-RED RIVER-SEVIER-
1204 AM CDT SUN OCT 23 2011

...SIGNIFICANT WEATHER ADVISORY...

THE NATIONAL WEATHER SERVICE IN SHREVEPORT HAS ISSUED A SIGNIFICANT
WEATHER ADVISORY...EFFECTIVE UNTIL 100 AM CDT...FOR THE FOLLOWING
COUNTIES...

IN SOUTHWEST ARKANSAS...
     HOWARD...LITTLE RIVER AND SEVIER...
IN SOUTHEAST OKLAHOMA...
     MCCURTAIN...
IN NORTHEAST TEXAS...
     RED RIVER AND BOWIE...

INCLUDING THE FOLLOWING LOCATIONS...
     ALLEENE...ARKINDA...ASHDOWN...ATHENS...BEN LOMOND...DE QUEEN...
     DIERKS...FOREMAN...GILLHAM...HORATIO...LOCKESBURG...OGDEN...
     RICHMOND...UMPIRE...WILTON...WINTHROP...BOGATA...BOXELDER...
     DALBY SPRINGS...DE KALB...HOOKS AND NEW BOSTON...

AT 1159 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS WERE
DETECTING A LINE OF STRONG THUNDERSTORM...NEAR THE OKLAHOMA AND
ARKANSAS STATE LINE...EXTENDING SOUTHWEST TO NEAR CLARKVILLE TEXAS.
THESE STORMS ARE MOVING TO THE EAST SOUTHEAST NEAR 50 MPH.

PEA SIZE HAIL...AND WINDS AROUND 40 MPH ARE EXPECTED WITH THESE STORMS.

VII

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
1220 AM CDT SUN OCT 23 2011

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

1155 PM     TSTM WND GST     5 SW IDABEL             33.85N 94.88W
10/22/2011  M64 MPH          MCCURTAIN          OK   MESONET

            MEASURED AT THE IDABEL MESONET STATION.

&&

15

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE SHREVEPORT LA
1250 AM CDT SUN OCT 23 2011

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

1135 PM     TSTM WND DMG     VALLIANT                34.00N 95.09W
10/22/2011                   MCCURTAIN          OK   EMERGENCY MNGR

            POWER POLE AND LINES DOWN. SEVERAL TREES BLOWN DOWN ALONG
            WITH A TREE ON A VEHICLE.

&&

ASTEVENS