MESOSCALE DISCUSSION 2264
NWS STORM PREDICTION CENTER NORMAN OK
0616 PM CDT SUN SEP 26 2004

AREAS AFFECTED...NRN FL THROUGH SE GA
CONCERNING...TORNADO WATCH 841...

VALID 262316Z - 270115Z ( 716pm EDT - 916pm EDT)
BEST THREAT FOR ISOLATED TORNADOES THROUGH 02Z IS EXPECTED FROM NERN FL NEAR THE JACKSONVILLE AREA NWD INTO PART OF SERN GA.

EARLY THIS EVENING THE CENTER OF TROPICAL STORM JEANNE WAS LOCATED OVER THE NWRN FL PENINSULA AND CONTINUES TO MOVE IN A GENERAL NNWWD DIRECTION. PERSISTENT ELY LOW LEVEL FLOW HAS RESULTED IN A VERY MOIST BOUNDARY LAYER WITH SURFACE DEWPOINTS IN THE MID 70S ADVECTING ONSHORE ACROSS NE FL AND INTO SE GA CONTRIBUTING TO SLIGHTLY HIGHER INSTABILITY. THE WWD MOVING RAINBANDS IN THE NE QUADRANT OF THE STORM ARE COLOCATED WITH THE BETTER INSTABILITY AND VERY STRONG LOW LEVEL SHEAR WITH 0-1 KM STORM RELATIVE HELICITY IN EXCESS OF 300 M2/S2. CURRENT RADAR DATA SHOW STRONG VELOCITY COUPLETS WITHIN THE MORE DISCRETE CONVECTIVE ELEMENTS MOVING WWD INTO THE JACKSONVILLE AREA. DISCRETE CELLS WITHIN THESE OUTER BANDS WILL CONTINUE TO HAVE THE BEST POTENTIAL TO PRODUCE ISOLATED TORNADOES NEXT FEW HOURS.
BEST THREAT AREA WILL GRADUALLY SHIFT NWD INTO SE GA WITH TIME.

..DIAL.. 09/26/2004