Severe Thunderstorm Warning 55, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
145 AM CST THU MAR 13 2003

FORECAST CHALLENGES
.SHORT TERM...
TO DETERMINE THE CHANCES OF SHOWERS AND THUNDERSTORMS
WITH LACK OF WIND SHEAR FOR TODAY THROUGH FRIDAY NIGHT...AS WELL AS
ITS AFFECT ON TEMPS.

.LONG TERM...
IT WILL BE TO ASSESS THE CHANCE OF SHOWERS AND THUNDERSTORMS
FOR SATURDAY THROUGH WEDNESDAY...ESPECIALLY WITH GOOD JET DYANMICS
FOR LATE MONDAY THROUGH WEDNESDAY.

...CURRENTLY...
A MILD ZONAL PATTERN WAS IN PLACE WITH A SHORT WAVE OVER THE
NORTHWEST DELTA REGION.  THIS WAS AHEAD OF A SHORT WAVE TROUGH THAT
OVER THE SOUTHERN PLAINS MOVING TOWARD THE LOWER MISSISSIPPI
VALLEY. CONVECTION WAS EXITING ACROSS THE SOUTHEAST...WITH NO
SIGNIFICANT WIND SHEAR OR JET DYNAMICS. ON THE SURFACE A FRONTAL
BOUNDARY EXTENDED FROM THE SOUTHERN PLAINS TO THE MIDDLE MISSISSIPPI
VALLEY. IT WAS MILD WITH TEMPS IN THE 60S. BROAD UPPER TROUGH THAT
WILL AFFECT OUR REGION EARLY NEXT WEEK WAS NOTED OVER THE EASTERN
PACIFIC.

SHORT TERM...TODAY THROUGH FRIDAY NIGHT...
THE MODELS SHOW THE FRONT COMING THROUGH THE REGION TODAY.
THE GFS HINTS OF AN MCS PUSHING ACROSS THE SOUTHERN TIER WITH BASIN
AMOUNTS AROUND AN INCH. WILL PUT THE BEST POPS IN THE SOUTH. THE
FRONT WILL SETTLE JUST SOUTH OF INTERSTATE 20 BY THIS EVENING. THE
SHORTWAVE TROUGH WILL MOVE INTO THE REGION FROM THE NORTHWEST. THE
FLOW WILL CONTINUE TO BE RATHER WEAK WITH SOME DEEP LAYERED SHEAR.
COLD MID LEVEL TEMPS WILL CONTRIBUTE TO LAPSE RATES OF ROUND 7
DEGREE C...MUCAPES 2000 TO 2500. FRONTAL BOUNDARY SHOULD HELP
PROVIDE LIFT FOR CONVECTIVE DEVELOPMENT. THE MAIN RISK FROM SOUNDING
PROFILES WILL BE HAIL FROM MUITICELL STORMS PER SPC. FORCING WILL BE
RATHER WEAK. FOR TONIGHT THE SHORT WAVE TROUGH WILL BECOME CLOSED AS
IT SETTLES OVER THE REGION. EXPECT ISOLATED TO SCATTERED SHOWERS AND
THUNDERSTORMS TO CONTINUE INTO THE OVERNIGHT HOURS. WILL KEEP BEST
SCATTERED POPS SOUTH HALF. THE MODELS ...INCLUDING THE UKMET PUSH
THE BOUNDARY TO THE COAST BY FRIDAY MORNING. ON FRIDAY THE CLOSED
UPPER LOW WILL LINGER OVER THE REGION WITH COOL MIDLEVEL TEMPS OF
AROUND 18 DEGREES. THE BEST MEAN MOISTURE WILL BE CENTRAL AND SOUTH.
THE CLOSED UPPER SYSTEM WILL CONTINUE TO HANG OVER THE REGION
THROUGH FRIDAY NIGHT. SO WITH SYSTEM AROUND WILL KEEP CONVECTIVE
POPS THROUGH FRIDAY NIGHT. WILL KEEP BEST SCATTERED POPS CENTRAL AND
SOUTH FOR FRIDAY/FRIDAY NIGHT.

WILL GO WITH A BLEND OF MAV/ETA TEMPS.

LONGTERM...SATURDAY THROUGH WEDNESDAY...
THE 00Z GFS FINALLY KICKS OUT THE UPPER CLOSED SYSTEM BY SATURDAY
EVENING....TAKING GOOD MEAN MOISTURE OUT WITH IT ON SATURDAY NIGHT.
ON SUNDAY SOUTHERLY FLOW REDEVELOPS ACROSS THE REGION AHEAD OF A
PACIFIC FRONTAL BOUNDARY MOVING THROUGH THE PLAINS. OF INTEREST IS A
BROAD UPPER TROUGH THAT WILL DEVELOP THE REGION ON LATE SUNDAY NIGHT
INTO EARLY NEXT WEEK. THE UPPER TROUGH IS CURRENTLY OVER THE EASTERN
PACIFIC.  GOOD LOWER AND UPPER JET DYNAMICS PUSHES INTO THE REGION
ON MONDAY...TRIGGERING THE POSSIBILITY OF SOME STRONG STORMS FOR TUESDAY.
THE CANADIAN...NOGAPS...UK...EUROPEAN...AND NOGAPS AGREE WITH THE
JET DYNAMICS OF THE BROAD UPPER TROUGH DEVELOPING FOR THE EARLY TO
THE MIDDLE PART OF NEXT WEEK. ALL MODELS PAINT A POTENT STORM SYSTEM
MOVING THROUGH THE REGION DURING THE PERIOD. WILL MAKE A SLIGHT
ADJUSTMENT TO EXTENDED BY PUTTING A SLIGHT CHANCE FOR SUNDAY. THE
REST OF EXTENDED APPEARS TO BE ON TRACK.

PRELIMINARY NUMBERS...
JAN 076/055/074/052/72 6433
MEI 076/054/074/050/68 6433

THANKS FOR THE COORDINATION KLIX

.JAN...
AR...NONE.
LA...NONE.
MS...NONE.
17

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
141200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
0404 AM CST THU MAR 13 2003

THIS HAZARDOUS WEATHER OUTLOOK IS FOR CENTRAL MISSISSIPPI...
NORTHEAST LOUISIANA...AND EXTREME SOUTHEAST ARKANSAS

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

...THUNDERSTORMS...
ISOLATED SEVERE THUNDERSTORMS WILL BE POSSIBLE OVER THE OUTLOOK
AREA TODAY. THE PRIMARY SEVERE WEATHER RISK WILL BE LARGE HAIL.
AN UPPER LEVEL TROUGH OF LOW PRESSURE WILL DEVELOP SOUTHWARD
ACROSS THE LOWER MISSISSIPPI VALLEY REGION THROUGH TONIGHT. AHEAD
OF THE TROUGH...THE ATMOSPHERE IS MOIST AND UNSTABLE...AND
FAVORABLE FOR THUNDERSTORM DEVELOPMENT. IT APPEARS THAT
THUNDERSTORMS WILL BE MOST NUMEROUS GENERALLY ALONG AND SOUTH OF
INTERSTATE 20...IN THE VICINITY OF A WEAK SURFACE BOUNDARY. AS
THE UPPER LEVEL TROUGH APPROACHES FROM THE NORTH...IT WILL
INTERACT WITH THE SURFACE BOUNDARY TO GENERATE NEW THUNDERSTORMS
LATER TODAY.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY...

...DAYS TWO AND THREE...
NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

...DAYS FOUR THROUGH SEVEN...
A LARGE AND POWERFUL SPRING STORM IS EXPECTED TO AFFECT THE
OUTLOOK AREA EARLY NEXT WEEK...PRIMARILY FROM LATE MONDAY INTO
EARLY WEDNESDAY. STRONG THUNDERSTORMS AND HEAVY RAINFALL ARE
LIKELY TO ACCOMPANY THIS SYSTEM. A STRONG JET STREAM CURRENTLY
OVER THE PACIFIC OCEAN...WILL DRIVE LARGE AMOUNTS OF POTENTIAL
STORM ENERGY INTO THE SOUTHERN PLAINS BY MONDAY...LEADING TO THE
DEVELOPMENT OF AN INTENSE LOW PRESSURE SYSTEM. SEVERAL ROUNDS OF
THUNDERSTORMS MAY DEVELOP OVER THE LOWER MISSISSIPPI VALLEY
REGION IN ASSOCIATION WITH THIS STORM SYSTEM...BEFORE A COLD
FRONT SWEEPS THROUGH BY EARLY WEDNESDAY.

.SPOTTER CALL TO ACTION STATEMENT...
THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL IN SUPPORT OF SEVERE WEATHER
OPERATIONS...MAY BE NECESSARY TODAY.

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.SRH.NOAA.GOV/JAN. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.