MESOSCALE DISCUSSION 0015
   NWS STORM PREDICTION CENTER NORMAN OK
   0125 PM CST SAT JAN 12 2013
   
   AREAS AFFECTED...PARTS OF FAR NERN TX / SWRN-CNTRL-NERN AR / MO
   BOOTHEEL
   
   CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY 
   
   VALID 121925Z - 122200Z
   
   PROBABILITY OF WATCH ISSUANCE...80 PERCENT
   
   SUMMARY...THE DEVELOPMENT AND/OR TRANSITION TO SURFACE-BASED STORMS
   IS EXPECTED TO BEGIN OVER THE NEXT SEVERAL HOURS.  ONCE THIS BECOMES
   APPARENT...A TORNADO WATCH WILL LIKELY BE NEEDED TO ADDRESS AN
   INCREASING THREAT FOR DMGG WINDS AND ISOLD TORNADOES BY THE LATE
   AFTERNOON THROUGH THE EVENING HOURS.
   
   DISCUSSION...19Z SURFACE MESOANALYSIS SHOWS A 1005 MB SURFACE LOW 30
   MI E DAL AND A COLD FRONT DRAPED SW TO NE FROM NEAR THE DFW
   METROPLEX THROUGH W-CNTRL AR AND INTO SERN MO.  THE SRN PORTION OF
   THE FRONT WILL ACCELERATE EWD INTO FAR NERN TX BY EARLY EVENING AS
   THE LOW DEVELOPS NEWD...BUT THE PORTION OF THE FRONT OVER AR IS
   EXPECTED TO MOVE LITTLE OR SLIGHTLY NWD OVER THE NEXT SEVERAL HOURS.
   AS SUCH...LOW LEVEL MOISTURE /MID-UPPER 60S DEWPOINTS/ LEADING TO A
   DESTABILIZING BOUNDARY LAYER WILL CONTINUE TO ADVANCE NWD INVOF THE
   FRONT OVER CNTRL-NERN AR.  
   
   DESPITE A THICK MID-HIGH LEVEL CLOUD CANOPY RETARDING SURFACE
   HEATING...TEMPS ARE GRADUALLY WARMING INTO THE LOW 70S OVER THE
   ARKLATEX REGION.  THIS HAS CONTRIBUTED TO UPWARDS OF 1500 J/KG
   MLCAPE WHEN MODIFYING THE 12Z SHV RAOB --FEATURING A 14-15 G/KG MEAN
   MIXING RATIO-- FOR THE 19Z TXK SURFACE OBSERVATION.  MOIST LOW
   LEVELS COMBINED WITH A STRENGTHENING LLJ TO 55 KTS BY 00Z...WILL
   ENLARGE HODOGRAPHS /500 M2/S2 0-1 KM SRH/ AND FACILITATE AT LEAST
   THE POTENTIAL FOR DMGG WINDS AND ISOLD TORNADOES WITH A MESSY
   CONVECTIVE MODE FOCUSED NEAR THE FRONT.
   
   ..SMITH/HART.. 01/12/2013
   
   
   ATTN...WFO...MEG...LZK...SHV...
   
   LAT...LON   33259505 35209298 36489070 36118939 33529313 32669484
               33259505