Severe Thunderstorm Warning 253, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
317 PM CDT FRI MAY 02 2003

FORECAST CHALLENGES INCLUDED PLACEMENT AND STRENGTH OF CONVECTION
TODAY AND TOMORROW AND RAIN CHANCES GOING INTO THE EXTENDED.

CURRENT SURFACE ANALYSIS OF THE SOUTHERN U.S. SHOWS A COLD FRONT
LOCATED ACROSS SOUTHEAST OKLAHOMA AND CENTRAL ARKANSAS. ANOTHER WEAK
SURFACE TROUGH LIES TO THE SOUTHEAST...ORIENTED SOUTHWEST TO
NORTHEAST ACROSS NORTHERN LOUISIANA...SOUTHEAST ARKANSAS...AND
NORTHWEST MISSISSIPPI. THIS FEATURE IS PART OF A REMAINING OUTFLOW
BOUNDARY FROM AN OVERNIGHT CONVECTIVE COMPLEX THAT RAPIDLY DECAYED
AS IT CAME INTO OUR CWA BEFORE DAWN.

WITH TEMPERATURES IN THE MIDDLE TO UPPER 80S ACROSS THE ENTIRE AREA
AND SKIES GENERALLY PARTLY CLOUDY...THE ATMOSPHERE IS BECOMING VERY
UNSTABLE. THE LIMITED CAP TO CONVECTION HAS BEEN OVERCOME IN THE
PAST FEW HOURS ALONG THE SURFACE BOUNDARY MOVING INTO NORTHERN
MISSISSIPPI AND ANOTHER WEAKER BOUNDARY PUSHING SOUTH INTO THE
NORTHEAST CWA. ESTIMATED CAPE VALUES AT PRESENT ARE NEAR 4000 J/KG
AND THIS MASSIVE AMOUNT OF CONVECTIVE ENERGY IS EXPECTED TO BRING
STORMS TO SEVERE LEVELS DESPITE SOMEWHAT MARGINAL WIND SHEAR. THE
MAIN RISK WITH THESE STORMS WILL COME FROM HAIL AND HIGH
WINDS...ALTHOUGH AN ISOLATED TORNADO IS NOT OUT OF THE QUESTION.
STORMS OVER SOUTHERN CWA COULD ALSO BE SEVERE BUT SHOULD BE MORE
ISOLATED DUE TO LACK OF CONVERGENCE TO INITIATE STORMS. THIS
CONVECTION WILL BE PRIMARILY DIURNALLY DRIVEN SO EXPECT A RAPID
DECREASE LATER THIS EVENING ALTHOUGH WILL STILL KEEP POPS IN TO
ACCOUNT FOR THE WEAK FRONT ENCROACHING FROM THE NORTHWEST AND
RESIDUAL PRECIPITATION.

MODELS STILL EXPECT THE COLD FRONT TO PUSH WELL SOUTH INTO THE CWA
TOMORROW. OUR FORECAST WILL TREND TOWARD KEEPING THE FRONT FURTHER
NORTH BEFORE INCREASING SOUTHERLY FLOW EARLY SUNDAY MOVES IT BACK
NORTHWARD. MORE THUNDERSTORMS SHOULD FORM AROUND THIS SEMI-STALLED
FRONT BISECTING THE CWA SATURDAY. SHEAR VALUES WILL INCREASE NORTH
OF THE BOUNDARY BUT SLIGHTLY COOLER AND DRIER AIR NEAR THE SURFACE
SHOULD LIMIT CONVECTION. ALTHOUGH WIND SHEAR WILL BE WEAK TO THE
SOUTH...ENOUGH INSTABILITY WILL BE PRESENT TO PRODUCE ISOLATED
SEVERE STORMS AGAIN.  SATURDAY NIGHT STRONG WARM ADVECTION SETTING
UP IN THE AREA WILL BRING A RISK OF WIDESPREAD ELEVATED STORMS NORTH
OF FRONT. THE PLACEMENT OF THIS PRECIPITATION WILL DEPEND ON HOW FAR
SOUTH THE FRONT MOVES BEFORE STALLING. OUR FORECAST WILL PINPOINT
LOCATIONS NORTH OF I-20 WITH BEST CHANCES OVER THIS TIME PERIOD
ALTHOUGH ALL OTHER LOCATIONS IN THE WARM SECTOR WILL STILL HAVE
SLIGHT CHANCES. AS THE WARM FRONT SLIDES NORTH OF THE ENTIRE CWA
SUNDAY AFTERNOON TEMPERATURES...MOISTURE...AND SURFACE WINDS WILL
INCREASE. ISOLATED STORMS WILL BE POSSIBLE...ESPECIALLY IN THE
NORTHERN HALF OF MISSISSIPPI WHERE A STRONG MID LEVEL SPEED MAX
MOVING IN WILL HELP SPAWN CONVECTION. ATMOSPHERIC PARAMETERS WILL
BE SUITABLE FOR SEVERE STORMS SO THIS TIME PERIOD WILL BE EXAMINED
MORE CLOSELY IN SUBSEQUENT FORECASTS.

EXTENDED:

MODEL CONSENSUS KEEPS THE AXIS OF A 500 MB TROUGH ANCHORED OVER THE
SOUTHWEST U.S. THROUGH THE LATTER PART OF NEXT WEEK. THIS SITUATION
LOOKS TO RESULT IN CONTINUED UNSETTLED WEATHER OVER OUR AREA. THE
FRONTAL BOUNDARY MOVING DOWN INTO THE LOWER MISSISSIPPI VALLEY
MONDAY WILL NOT HAVE ENOUGH PUSH TO GET SOUTH OF US AND MAY END UP
OSCILLATING NORTH AND SOUTH IN THE VICINITY.  SHORT WAVES MOVING
THROUGH THE FLOW WILL PROVIDE THE IMPETUS FOR SURFACE LOW FORMATION
ALONG THIS BOUNDARY. A SOUPY AIR MASS SHOULD REMAIN IN PLACE OVER
OUR AREA DURING THIS PERIOD SO THERE WILL BE ENOUGH FUEL IN THE
ATMOSPHERE FOR WIDESPREAD SHOWERS AND THUNDERSTORMS.  MODELS SHOW
THE MOST SIGNIFICANT SHORT WAVES TO PASS THROUGH THE FLOW MONDAY AND
THURSDAY AND THE CHANCES FOR STRONG STORMS WILL INCREASE ON THESE
DAYS.  LOOKING IN FINER DETAIL AT MONDAY...JET ENERGY...SHEAR
VALUES...FORCING...AND LOW LEVEL WIND FIELDS WILL INCREASE AHEAD OF
COLD FRONT FORECAST TO MOVE INTO ARKLAMISS BY AFTERNOON. IF OUR CWA
IS FIRMLY EMBEDDED IN THE WARM SECTOR DURING THE AFTERNOON THEN
NORTHERN AND WESTERN PORTIONS HAVE A GOOD CHANCE AT SEEING SOME
POWERFUL STORMS.  EXAMINING FINER DETAIL THROUGH THE REST OF THE
EXTENDED IS NOT WISE AT THIS POINT...BUT I CAN SAY THAT THE
POSSIBILITY OF CONTINUED RAIN OVER SATURATED GROUND COULD HAVE
IMPLICATIONS FOR MORE FLOODING.

PRELIMINARY NUMBERS...
JAN EE 065/085 065/086 068 63233
MEI EE 063/084 062/086 068 63332

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

50

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
031200-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
141 PM CDT FRI MAY 02 2003

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

.DAY ONE...TONIGHT AND SATURDAY...

...THUNDERSTORMS...
A WEAK SURFACE BOUNDARY WILL MOVE INTO THE ARKLAMISS REGION EARLY
THIS AFTERNOON. THIS BOUNDARY COMBINED WITH ABUNDANT MOISTURE AND
STRONG INSTABILITY WILL CAUSE THE DEVELOPMENT OF SCATTERED SEVERE
THUNDERSTORMS. THE MORE CONCENTRATED STORMS WILL FIRST DEVELOP
NORTH OF INTERSTATE 20...MAINLY ALONG THE HIGHWAY 82
CORRIDOR...AFTER 3 PM. THE PRIMARY THREAT WITH THESE STORMS WILL
BE LARGE HAIL AND DAMAGING WINDS. AFTER SUNSET...THE SURFACE
BOUNDARY COMBINED WITH NUMEROUS OUTFLOW BOUNDARIES WILL CAUSE
CONVECTION TO DEVELOP SOUTHWARD. HOWEVER...DUE TO THE LOSS OF
DAYTIME HEATING...ONLY ISOLATED SEVERE COVERAGE IS EXPECTED.

FOR SATURDAY...LINGERING SURFACE BOUNDARIES FROM TODAYS
CONVECTION WILL HELP DEVELOP THUNDERSTORMS SATURDAY AFTERNOON.
STRONG INSTABILITY WILL ONCE AGAIN BE IN PLACE...BUT DUE TO A
LACK OF UPPER LEVEL SUPPORT...ONLY ISOLATED SEVERE STORMS ARE
EXPECTED.

.DAYS TWO THROUGH SEVEN...SATURDAY NIGHT THROUGH FRIDAY...

...DAYS TWO AND THREE...
STORMS WILL BE ONGOING ACROSS PORTIONS OF THE AREA SATURDAY
EVENING DUE TO THE LINGERING SURFACE BOUNDARY ACROSS THE AREA. AS
HEATING IS LOST DURING THE EVENING...STORMS WILL GRADUALLY
DIMINISH IN INTENSITY.

FOR SUNDAY...THE SURFACE BOUNDARY WILL FINALLY LIFT TO THE NORTH
AS A WARM FRONT. MOISTURE AND INSTABILITY WILL QUICKLY RETURN
ACROSS THE ENTIRE REGION. A STRONG MID LEVEL JET WILL ALSO MOVE
INTO SOUTHERN ARKANSAS...ENHANCING THE LIFT AND ALLOWING FOR
STORMS TO DEVELOP. THE MAIN CONCENTRATION OF STRONG TO SEVERE
STORMS WILL BE ALONG AND NORTH OF THE HIGHWAY 82 CORRIDOR.

...DAYS FOUR THROUGH SEVEN...
ANOTHER FRONTAL SYSTEM WILL MOVE THROUGH THE AREA MONDAY NIGHT
THROUGH TUESDAY. THE SURFACE BOUNDARY AND UPPER LEVEL JET SUPPORT
WILL COMBINE WITH MOISTURE AND INSTABILITY TO AGAIN PRODUCE
STRONG THUNDERSTORMS. THIS FRONT WILL STALL ACROSS THE
AREA...KEEPING A CHANCE FOR STRONG THUNDERSTORMS TO DEVELOP
THROUGH WEDNESDAY. THIS BOUNDARY WILL LIFT AS A WARM FRONT
THURSDAY AS ANOTHER FRONTAL SYSTEM APPROACHES. THIS COLD FRONT
WILL MOVE THROUGH THE AREA ON FRIDAY...AGAIN POSSIBLY PRODUCING
STRONG THUNDERSTORMS.

THE LOCATION AND INTENSITY OF THESE STORM SYSTEMS REMAINS
UNCERTAIN. CONTINUE TO MONITOR THE LATEST FORECAST AND STATEMENTS
FOR MORE INFORMATION.

.SPOTTER CALL TO ACTION STATEMENT...
THE ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND
EMERGENCY MANAGEMENT PERSONNEL...IN SUPPORT OF SEVERE WEATHER
OPERATIONS...WILL LIKELY BE NEEDED THROUGH TONIGHT.

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

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
214 PM CDT FRI MAY 02 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0205 PM    1 NE PHEBA                MS   0.88 INCH HAIL
05/02/03   CLAY                           REPORTED BY MS STATE
                                          STORM CHASERS.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
300 PM CDT FRI MAY 2 2003

TIME(CST)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0241 PM    6 SE OF COLUMBUS          MS     0.75 INCH HAIL
           LOWNDES                          REPORTED BY NWS
                                            SPOTTER. MILE MARKER
                                            6 ON HWY 69.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE JACKSON MS
436 PM CDT FRI MAY 02 2003

TIME(CDT)  .....CITY LOCATION..... STATE  ...EVENT/REMARKS...
           ....COUNTY LOCATION....

0425 PM    DESOTO                    MS   1.75 INCH HAIL
05/02/03   CLARKE                         REPORTED BY CLARKE COUNTY
                                          EMA.