SPC MESOSCALE DISCUSSION 0399 FOR SE AR/CNTRL MS/W CNTRL AL
CONCERNING...SEVERE THUNDERSTORM POTENTIAL/HEAVY RAIN...SEVERE
THUNDERSTORM WATCH 88

VALID 040419Z - 040700Z

WW WILL LIKELY BE CANCELLED BY 0430Z.

NEW CONVECTIVE DEVELOPMENT CONTINUES TO DEVELOP ALONG OUTFLOW
BOUNDARY EXTENDING FROM SOUTHEASTERN ALABAMA CONVECTIVE CLUSTER
THROUGH WEST CENTRAL ALABAMA...NORTHEAST OF MERIDIAN MS...TO NEAR
GREENVILLE MS.  AS UPSTREAM SHORT WAVE...NOW MIGRATING THROUGH
LARGE-SCALE RIDGE AXIS OVER ARKANSAS/LOUISIANA...CONTINUES EAST
SOUTHEASTWARD OVERNIGHT...FORCING FOR UPWARD VERTICAL MOTION WILL
HELP MAINTAIN STRONG CONVECTIVE DEVELOPMENT.  WITH ACTIVITY LIKELY
TO REMAIN MOSTLY ON COOL SIDE OF SURFACE BOUNDARY...SEVERE THREAT
WILL LIKELY DIMINISH...BECOMING LIMITED TO ISOLATED LARGE HAIL
ALONG SOUTHERN BOUNDARY OF WW 88.  

PRIMARY THREAT OVERNIGHT WILL BE LOCALLY EXCESSIVE RAINFALL...
SUPPORTED BY LIFT OF VERY MOIST AIR MASS WITH SURFACE DEW POINTS
NEAR 70F.  TRAINING OF CELLS APPEARS LIKELY...AS BAND OF CONFLUENT
LOW-LEVEL FLOW BECOMES QUASISTATIONARY FROM AREAS OF CENTRAL
MISSISSIPPI TO THE SOUTH OF GREENWOOD...INTO SOUTH CENTRAL ALABAMA
...SOUTH OF SELMA.

..KERR.. 04/04/01