Severe Thunderstorm Warning 3, NWS Shreveport, LA

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE SHREVEPORT LA
200 PM CST WED MAR 12 2003

SHOWERS AND THUNDERSTORMS ASSOCIATED WITH UPPER DISTURBANCE TRACKING
ALONG THE GULF COAST...ARE EXPECTED TO EXIT THE FORECAST AREA DURING
THE LATE AFTERNOON/EARLY EVENING.  WILL HAVE LOW POPS ACROSS THE
EASTERN THIRD FOR THIS ACTIVITY...BUT WILL LOOK AT RADAR RETURNS AT
ISSUANCE TIME FOR FINAL DECISION.

THEN THE FOCUS TURNS NORTHWARD NEAR A WARM FRONT ACROSS S KS/S
MO...WHERE SHOWERS AND THUNDERSTORMS WILL DEVELOP LATER THIS EVENING
AS THE NOCTURNAL LOW LEVEL JET KICK IN.  THIS COMPLEX OF SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO MOVE ESE...WITH THE THUNDERSTORMS
PROGGED TO DEVELOP SOUTHWESTWARD AND MOVE INTO SE OK/SW AR AND
ADJACENT AREAS OF NE TX...MAINLY NW OF INTERSTATE 30 DURING THE
OVERNIGHT HOURS.  THE ACTIVITY IS EXPECTED TO WEAKEN AS IT MOVES
INTO THE FORECAST AREA.

THE SHOWER AND THUNDERSTORM ACTIVITY IS THEN EXPECTED TO AFFECT
MAINLY THE SOUTHERN 3/4 OF THE REGION ON THURSDAY AS DIFFUSE FRONT
PUSHES THROUGH THE REGION.

WEAK UPPER SUPPORT AND LACK OF A GOOD SURFACE BOUNDARY...SHOULD
PRECLUDE ORGANIZED SEVERE THUNDERSTORMS...BUT INSTABILITY /CAPE OVER
1000 AND LI GENERALLY -3 TO -6/ IS DECENT...IN COMBINATION WITH
700-500 MB LAPSE RATES GENERALLY BETWEEN 7 AND 8 DEGREES...TO HAVE
AN ISOLATED SEVERE THUNDERSTORM.  THE PRIMARY THREAT WITH ANY SEVERE
THUNDERSTORM WOULD BE LARGE HAIL.  WILL NOT MENTION IN ZONES...AS
SEVERE THREAT SHOULD BE ISOLATED.

THE ZONAL FLOW OVER THE COUNTRY TODAY...WILL TRANSITION TO TROUGHS
ON THE EAST AND WEST COAST...WITH A RIDGE ACROSS THE MIDSECTION OF
THE COUNTRY...ON THURSDAY.  HOWEVER...THE SOUTHERN PART OF THE
EASTERN SEABOARD TROUGH...WILL BECOME SHEARED...AND WILL TRY TO
BECOME CUT OFF...UNDER THE RIDGE ACROSS THE NORTHERN PART OF THE
COUNTRY.  WITH LITTLE FLOW ALOFT...THIS CUT OFF LOW OR VORTICITY MAX
WILL MEANDER ACROSS THE GULF COAST REGION THROUGH AT LEAST THE FIRST
PART OF THE WEEKEND.   THE ETA IS FURTHER EAST THAN THE GFS WITH THE
CLOSED LOW...AND THUS IS ENDING THE RAIN EARLIER.  WILL HAVE THE
AREA DRYING OUT FRIDAY...WITH MAIN POPS OUT EAST.  IF THE GFS IS
CORRECT...THE AREA MIGHT HANG ON TO SOME RAIN THROUGH SATURDAY.

IN THE EXTENDED...THE TROUGH ACROSS THE WEST COAST WILL MOVE OVER
THE ROCKIES...WHICH COULD SET UP A RAINY PERIOD FOR THE BEGINNING OF
THE WEEK.  THE 12Z GFS HAS TAPERED THE AMOUNT OF MOISTURE WITH THIS
SYSTEM...COMPARED TO THE 00Z GFS.  WILL GO BELOW MEX POP MOS...WITH
ONLY SLIGHT TO CHANCE POPS FOR NOW.

22

PRELIMS...

SHV 063/078 056/073 2422
MLU 061/078 055/070 3433
TXK 062/079 054/071 3322
TYR 064/079 056/075 2423
LFK 063/078 056/075 1423

.SHV...NONE.

ARZ050-051-059>061-070>073-LAZ001>006-010>014-017>022-OKZ077-TXZ096-
097-108>112-124>126-136>138-149>153-165>167-131200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE SHREVEPORT LA
1200 PM CST WED MAR 12 2003

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

.DAY ONE...THIS AFTERNOON AND TONIGHT...
AN UPPER LEVEL DISTURBANCE MOVING ALONG THE GULF COAST...WILL
PRODUCE SCATTERED SHOWERS AND THUNDERSTORMS THIS AFTERNOON AND
EVENING...MAINLY ALONG AND TO THE SOUTH OF INTERSTATE 20.  LATER
TONIGHT...ANOTHER AREA OF SHOWERS AND THUNDERSTORMS OVER OKLAHOMA
AND ARKANSAS...MAY MOVE INTO SOUTHEAST OKLAHOMA...SOUTHWEST ARKANSAS
AND ADJACENT AREAS OF NORTHEAST TEXAS.  AN ISOLATED SEVERE
THUNDERSTORM IS POSSIBLE...BUT ORGANIZED SEVERE WEATHER IS NOT
EXPECTED THIS AFTERNOON OR TONIGHT.  IF SEVERE THUNDERSTORMS DO
OCCUR...THE MAIN THREAT WOULD BE FROM LARGE HAIL.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.SPOTTER CALL TO ACTION STATEMENT...
ACTIVATION OF EMERGENCY MANAGERS...SKYWARN NETWORKS...AND STORM
SPOTTERS IS NOT EXPECTED THIS AFTERNOON OR TONIGHT.