Severe Thunderstorm Warning 362, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
245 PM CDT WED JUN 14 2000

SHOWER AND THUNDERSTORM ACTIVITY IS MOVING INTO THE FORECAST AREA
FROM TWO DIRECTIONS THIS AFTERNOON. FROM THE SOUTH...SCATTERED
SHOWERS AND A FEW THUNDERSTORMS ARE PLENTIFUL IN THE SOUTHERN HALF
OF THE STATE AND IN MUCH OF LOUISIANA. A FEW OF THESE PULSE
THUNDERSTORMS COULD APPROACH SEVERE LIMITS IN THE AFTERNOON AND
EARLY EVENING WITH STRONG DOWNBURST WINDS. SCATTERED SHOWERS AND
THUNDERSTORMS HAVE ALSO DEVELOPED ACROSS PORTIONS OF NORTHWEST
MISSISSIPPI AND SOUTHEASTERN ARKANSAS. NORTHWEST OF THE FORECAST
AREA...WIDESPREAD SHOWER AND THUNDERSTORM ACTIVITY IS OCCURRING TO
THE EAST OF AN UNSEASONABLY STRONG COLD FRONT AND UPPER LEVEL
TROUGH. THE FRONT IS NOT EXPECTED TO MOVE THROUGH THE FORECAST
AREA...BUT WILL HELP TO INCREASE LOW LEVEL CONVERGENCE AHEAD OF THE
FRONT...LEADING TO WIDESPREAD CONVECTION THIS AFTERNOON AND
TONIGHT...ESPECIALLY IN NORTHWESTERN SECTIONS.

THERE WILL BE A SLIGHT CHANCE OF A FEW SEVERE THUNDERSTORMS LATE
THIS AFTERNOON AND EARLY THIS EVENING IN THE NORTHWESTERN PART OF
THE FORECAST AREA WHERE LIMITED UPPER LEVEL DIVERGENCE IS EXPECTED
TO OCCUR. THE NORTHWESTERN PART OF THE FORECAST AREA WILL ALSO BE
CLOSER TO THE SURFACE COLD FRONT AND UPPER LEVEL TROUGH. CAPES IN
THIS AREA ARE FORECAST TO BE 1500 - 2000 J/KG LATE THIS AFTERNOON
ACCORDING TO THE LATEST ETA MODEL FORECAST. THE MAIN SEVERE WEATHER
THREAT WILL BE FOR STRONG WINDS AND (LESS THAN QUARTER SIZED) HAIL.

IN THE SOUTHERN HALF OF THE FORECAST AREA...SHOWER AND THUNDERSTORM
ACTIVITY SHOULD DECREASE IN AREAL COVERAGE AND INTENSITY AFTER
SUNSET. IN NORTHERN SECTIONS...SHOWERS AND THUNDERSTORMS MAY
CONTINUE LATER INTO THE NIGHT DUE TO THE UPPER LEVEL DYNAMICS...BUT
LOSS OF HEATING WILL ALSO CAUSE THESE STORMS TO GRADUALLY WEAKEN.
FOR FRIDAY...NGM AND ETA MODELS KEEP MUCH OF THE FORECAST AREA...
ESPECIALLY WESTERN SECTIONS...RELATIVELY DRY. HOWEVER...THE AVN
GUIDANCE KEEPS THE POPS UP AT AROUND 50 PERCENT. WILL GENERALLY LEAN
TOWARD NGM/ETA MODEL GUIDANCE AND WILL FORECAST 20 TO 30 PERCENT
CHANCE OF AFTERNOON SHOWERS AND THUNDERSTORMS FOR THURSDAY WITH ONLY
SLIGHT CHANCE EARLY EVENING POPS FOR WEDNESDAY NIGHT. FOR FRIDAY...
THE AVN CONTINUES TO HAVE THE HIGHEST POPS FORECAST. HOWEVER...I
WILL GO WITH 20 TO 30 PERCENT POPS FOR FRIDAY AND FRIDAY NIGHT IN
LINE WITH THE NGM GUIDANCE.

TEMPERATURES: WILL CONTINUE TO HAVE AMPLE LOW LEVEL MOISTURE THE
NEXT SEVERAL DAYS. THEREFORE...THERE WILL BE PLENTY OF AFTERNOON
CUMULUS CLOUDS DEVELOPING ACROSS THE AREA. HOWEVER...BELIEVE AVN'S
FORECAST DIURNAL TEMPERATURE RANGE IS TOO SMALL. WILL STICK CLOSER
TO NGM GUIDANCE. EVEN WITH NGM GUIDANCE...EXPECT MAX TEMPS TO REMAIN
SLIGHTLY BELOW NORMAL THE NEXT TWO DAYS WITH HIGH TEMPERATURES IN
THE UPPER 80S ACROSS THE FORECAST AREA.

QPF DISCUSSION: THE DYING OUTFLOW BOUNDARY SHOULD BE MAIN FOCUS FOR
PRECIPITABLE WATER VALUES OF 1.6-1.8" OVER NWRN PORTIONS OF CWFA
TONIGHT AND THURSDAY. NCEP FORECASTS OF 1/4 TO 1/2 INCH AMOUNTS OVER
24 HOURS LOOK FAIRLY REASONABLE CONCENTRATING IN THE FIRST AND LAST
6 HOUR PERIODS. THESE AMOUNTS ARE LESS THAN THE ETA BUT SLIGHTLY
MORE THAN AVN PROGS. LOCALLY HIGHER TOTALS ARE LIKELY DUE TO
POTENTIAL FOR SOME TRAIN ECHO EFFECTS LATE TONIGHT IN THE DELTA
REGION.

EXTENDED DISCUSSION: THE MRF MODEL SHOWS ANOTHER FRONTAL BOUNDARY
APPROACHING THE FORECAST AREA AND STALLING OUT ACROSS NORTHERN
MISSISSIPPI BY MONDAY MORNING. THE UKMO ALSO SHOWS A WEAK FRONT
STALLED ACROSS THE REGION. THE SOUTHERLY FLOW SOUTH OF THIS FRONTAL
BOUNDARY WILL ENSURE A CONTINUED CHANCE OF MAINLY AFTERNOON AND
EVENING SHOWERS AND THUNDERSTORMS THROUGH THE PERIOD.

PRELIM NUMBERS
JAN 70/89/70/89  3213
MEI 69/88/69/89  3312

.JAN...
MS...NONE.
AR...NONE.
LA...NONE.
15/40O

ARZ074-075-LAZ007>009-015-016-023>026-MSZ018-019-025>066-072>074-
150400-

AREA THUNDERSTORM OUTLOOK
NATIONAL WEATHER SERVICE JACKSON MS
1015 AM CDT WED JUN 14 2000

AN ABUNDANCE OF MOISTURE AND INSTABILITY ACROSS THE REGION THIS
MORNING WILL SET THE STAGE FOR SCATTERED THUNDERSTORMS BEGINNING
LATE THIS AFTERNOON THROUGH TONIGHT. AN UPPER LEVEL DISTURBANCE AND
SURFACE OUTFLOW BOUNDARY WILL APPROACH THE DELTA EARLY TONIGHT
CAUSING ISOLATED STORMS TO BECOME SEVERE.

A SLIGHT RISK FOR SEVERE WEATHER WILL EXIST MAINLY NORTH OF A
BASTROP...LOUISIANA TO BELZONI TO WEST POINT LINE BETWEEN 4 PM AND
MIDNIGHT. THE MAIN THREAT FROM THE STORMS WILL BE DAMAGING WINDS...
VERY HEAVY RAIN AND POSSIBLY HAIL.

ACTIVATION OF STORM SPOTTERS...HAM RADIO OPERATORS...AND EMERGENCY
MANAGEMENT PERSONNEL MAY BE NEEDED DURING THE EVENING HOURS.

FOR MORE INFORMATION...PLEASE VISIT OUR INTERNET WEB SITE AT
HTTP://WWW.SRH.NOAA.GOV/JAN WHICH INCLUDES AN EXPERIMENTAL GRAPHICAL
HAZARDOUS WEATHER OUTLOOK.