MESOSCALE DISCUSSION 2227
   NWS STORM PREDICTION CENTER NORMAN OK
   0538 PM CDT THU SEP 16 2004
   
   AREAS AFFECTED...ERN AL...NRN/CNTRL GA...SC
   
   CONCERNING...TORNADO WATCH 828...830...
   
   VALID 162238Z - 170045Z
   
   BRIEF TORNADOES ARE STILL POSSIBLE THIS EVENING.  TORNADO WATCHES
   828/830 WILL EXPIRE AT 01Z.  IT IS NOT CERTAIN IF ANY EXTENTIONS
   WILL BE NECESSARY.  
   
   HIGHEST PROBABILITIES FOR BRIEF TORNADOES APPEAR TO BE SHRINKING IN
   AREAL COVERAGE THIS EVENING WITH THE GREATEST THREAT ACROSS
   CNTRL/NERN GA AND CNTRL SC.  22Z MESOANALYSIS PLACED TROPICAL STORM
   IVAN OVER NCNTRL AL WITH A WARM FRONT SITUATED EWD ACROSS NRN GA
   INTO CNTRL SC. STRONGEST SPIRAL RAINBAND WAS ARCING SWD FROM JUST
   EAST OF KATL-KMCN.  OTHER TSTMS...WHICH HAVE EXHIBITED LOW-LEVEL
   ROTATION...WERE MIGRATING RAPIDLY NWWD INTO UPSTATE SC VCNTY KAND. 
   STRONGEST LOW LEVEL SHEAR EXISTS ALONG THE WARM FRONT...ESPECIALLY
   WHERE THESE SPIRAL RAINBANDS INTERSECT FROM 30 E KATL-KAND.  
   
   FARTHER EAST OVER ERN SC...CONVECTION WILL LIKELY BE MORE TIED TO
   DIURNAL INFLUENCES AND THE TORNADO THREAT MAY NOT MATERIALIZE THIS
   EVENING.  GIVEN THAT THE TROPICAL STORM IS HEADING SLOWLY NWD TOWARD
   STRONGEST PRESSURE FALL AXIS INTO NRN AL/MIDDLE TN...THE MOST
   INTENSE SPIRAL RAINBANDS SHOULD REMAIN ALONG/WEST OF THE SAVANNAH
   RIVER THIS EVENING.
   
   IT IS NOT CLEAR WHETHER A SMALL ADDITIONAL TORNADO WATCH WILL BE
   NEEDED AFTER 01Z.  ETA 3-HR PRESSURE FIELDS SEEM TO BE WEAKENING
   IVAN TOO RAPIDLY AND WOULD ARGUE FOR SLIGHTLY STRONGER LOW-LEVEL
   SHEAR THROUGH THE REMAINDER OF THE EVENING OVER NRN GA...UPSTATE SC
   AND PERHAPS ADJOINING WRN NC/ERN TN.  WILL MONITOR THE RAINBANDS
   THROUGH 01Z AND IF INTENSITY OR COVERAGE REMAINS THE SAME...AN
   ADDITIONAL WW MAY BE REQUIRED.
   
   ..RACY.. 09/16/2004
   
   
   ATTN...WFO...RAH...ILM...CHS...CAE...GSP...JAX...FFC...TAE...BMX...HUN...
   
   31868493 32648506 33258585 33438656 34938630 34938256
   34657889 31907951