Severe Thunderstorm Warning 646, NWS Jackson, MS

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE JACKSON MS
335 AM CDT FRI OCT 6 2000

PREFRONTAL TROUGH/WIND SHIFT LINE HAD JUST ENTERED NORTH MISSISSIPPI
AT 06Z. MODELS IN SIMILAR AGREEMENT WITH THE MOVEMENT OF THE
WINDSHIFT LINE INTO CENTRAL MISSISSIPPI AROUND SUNRISE AND SOUTH
MISSISSIPPI BY MIDDAY. THE ACTUAL FRONT/COLDER AIR IS PROGGED TO LAG
ANY WHERE FROM 3 TO 5 HOURS BEHIND THE WINDSHIFT.

06Z RADAR AND SATELLITE LOOPS SHOWED A SMALL BAND OF CONVECTION
ACROSS NORTH CENTRAL MISSISSIPPI WITH THE BULK OF THE PRECIP ALONG
AND BEHIND THE FRONT...LATEST TRENDS SHOWS AND INCREASE IN THE
PREFRONTAL PRECIP ALONG THE LOW LEVEL MOISTURE CONVERGENCE AXIS.
DEWPOINTS CURRENTLY RUNNING FROM THE LOW TO MID 70S.

THE QUESTION AT THIS TIME IS NOT WEATHER OR NOT WE WILL GET SOME
RAIN BUT HOW WIDESPREAD IT WILL BE. GUIDANCE GIVES LIKELY TO
WIDESPREAD CATEGORICAL POPS FOR TODAY ACROSS THE FORECAST AREA. IN
KEEPING WITH THE PREVIOUS FORECAST AND THE FACT THAT WE HAVE BEEN
WITHOUT SIGNIFICANT PRECIP FOR SO LONG WILL GO WITH AT LEAST THE
HIGH END LIKELY POPS. BY TONIGHT ALTHOUGH PLENTY OF LOW LEVEL
MOISTURE WILL REMAIN IN PLACE MOST OF THE LIFT WILL BE GONE IN THE
NORTH AND CENTRAL ZONES. WILL TRIM POPS CENTRAL TO SOUTH ACCORDINGLY.

THE NEXT ORDER OF BUSINESS WILL BE THE TEMPERATURES. GUIDANCE FOR
BOTH NGM AND AVN A LITTLE COOLER THAN PROGGED 24 HOURS AGO.  WITH
THE STRENGTH OF THE BUILDING SURFACE HIGH THE COOLER TEMPS WILL BE
BEST FOR THE LATTER PERIODS...THUS AVN/ETA. FOR TODAY... FALLING
HIGHS THROUGH THE AFTERNOON. FOR TONIGHT...THE EXTENSIVE CLOUD DECK
WILL PREVENT TEMPS FROM FALLING AS LOW AS PROJECTED BY AVN/ETA. COLD
STRATOCU BLANKET ON SATURDAY WILL NOT ALLOW FOR MUCH TEMP
VARIATION...SO MAX READINGS ON SATURDAY WILL ONLY BE ABOUT 5 TO 7
DEGREES HIGHER THAN THE MINS.  CLOUDS SHOULD GRADUALLY CLEAR
SATURDAY NIGHT. THE TIGHTENING GRADIENT WILL ALSO MAKE FOR SOME
BRISK CONDITIONS...WINDS OF 15 TO 25 MPH WILL BE COMMON. CURRENT
PACKAGE ALREADY INCLUDES CAUTION ON AREA LAKES.

24 HR QPF DISCUSSION: COLD FRONT CURRENTLY ALONG AN KPRX-KLIT-KMEM
LINE WILL MOVE INTO THE DELTA BY 12Z THEN ACROSS MOST OF THE
FORECAST AREA BY 00Z SAT. PRECIPITABLE WATER OF .75 TO 1.5 INCHES
WILL DECREASE TO AROUND .50 TO .75 INCH BY 12Z SATURDAY. THE NGM QPF
AMOUNTS OVER INTIALIZED AND THUS DRIED OUT POST FRONTAL RAINS TOO
EARLY. THE AVN OVER FORECASTED QPF AMOUNTS OF .50 TO AROUND 1.5
INCHES. PREFER THE ETA SOLUTION...WHICH INITIALIZED THE BEST AND
CAUGHT THE POST FRONTAL RAINFALL AMOUNTS OF .25 INCH NORTH TO AROUND
.75 INCH SOUTH BY 06Z SATURDAY...WITH LOCAL SPOTS OF ONE INCH IN THE
SOUTHEAST. NCEP HAS .25 INCH IN THE NORTH TO .50 INCH IN THE SOUTH.
GENERALLY ACCEPT THE ETA/NCEP SOLUTIONS.

CURRENT EXTENDED LOOKS GOOD. DRY WITH WELL BELOW CLIMO TEMPS THROUGH
THE PERIOD.

.PRELIM NUMBERS...
JAN 075/053 058/040 72-0
MEI 075/055 060/039 72-0

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