MESOSCALE DISCUSSION 2326
   NWS STORM PREDICTION CENTER NORMAN OK
   0218 PM CDT MON OCT 18 2004
   
   AREAS AFFECTED...CNTRL AR EWD ACROSS NRN MS
   
   CONCERNING...TORNADO WATCH 855...
   
   VALID 181918Z - 182015Z
   
   THE SHORT-TERM SEVERE WEATHER THREAT APPEARS TO BE DIMINISHING
   ACROSS AREA. THUS...WW WILL LIKELY BE ALLOWED TO EXPIRE AT 20Z.
   
   A GENERAL DECREASE IN TSTM INTENSITY HAS BEEN OBSERVED OVER THE PAST
   HALF HOUR OR SO ACROSS NRN MS. THOUGH AIR MASS HAS DESTABILIZED EWD
   AHEAD OF STORMS...IT APPEARS THAT LARGE-SCALE FORCING IS
   PROGRESSIVELY SHIFTING NE OF REGION INTO THE MIDDLE MS/ OH VALLEYS.
   FARTHER W ACROSS WRN/CNTRL AR...TEMPERATURES IN THE MID TO UPPER 80S
   COUPLED WITH DEWPOINTS IN THE UPPER 60S/LOWER 70S HAVE CONTRIBUTED
   TO A MODERATELY UNSTABLE AIR MASS WITH MLCAPES OF 2000-2500 J/KG
   /PER 18Z LZK SOUNDING/. HOWEVER...PASSAGE OF MID-LEVEL TROUGH HAS
   RESULTED IN VEERING LOW-LEVEL WIND FIELDS...DECREASING MID-LEVEL
   FLOW AND A SLIGHT WARMING OF MID-LEVEL TEMPERATURES.
   
   LATEST SHORT TERM MODEL GUIDANCE IS CONSISTENT IN RE-DEVELOPING
   STORMS OVER THE ARKLATEX REGION EARLY THIS EVENING. GIVEN CURRENT
   OBSERVATIONAL DATASETS...THERE REMAINS SOME UNCERTAINTY AS TO WHAT
   WOULD FORCE THE DEEP CONVECTION SUGGESTED BY THE MODELS. UNLESS
   ENVIRONMENTAL CLUES SUGGESTING REDEVELOPMENT ARE OBSERVED PRIOR TO
   20Z...WW WILL LIKELY BE ALLOWED TO EXPIRE.
   
   ..MEAD.. 10/18/2004
   
   
   ATTN...WFO...MEG...JAN...LZK...
   
   34889291 35408828 33938826 33479290