MESOSCALE DISCUSSION 0568
   NWS STORM PREDICTION CENTER NORMAN OK
   0654 PM CDT SAT APR 27 2013
   
   AREAS AFFECTED...SERN AR...NWRN LA...NERN TX
   
   CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE 
   
   VALID 272354Z - 280100Z
   
   PROBABILITY OF WATCH ISSUANCE...40 PERCENT
   
   SUMMARY...LATEST VISIBLE SATELLITE TRENDS SHOW CONVECTIVE
   DEVELOPMENT ALONG A COLD FRONT FROM SRN AR INTO NERN TX. A WINDOW OF
   OPPORTUNITY FOR DMGG WINDS AND LARGE HAIL MAY EXIST OVER THE NEXT
   COUPLE HRS...BUT DURATION OF THE THREAT REMAINS IN QUESTION...AND
   MAY PRECLUDE THE NEED FOR A WW ATTM.
   
   DISCUSSION...CONVECTIVE INITIATION HAS OCCURRED ALONG A SEGMENT OF
   COLD FRONT FROM SRN AR INTO NERN TX...ANALYZED FROM APPROXIMATELY 20
   SE LIT TO 10 W SHV AS OF 23Z. THIS AREA HAS BEEN LOCATED WITHIN A
   RELATIVE MINIMUM OF CONVECTIVE ACTIVITY THIS AFTERNOON...WITH
   STRONGEST FORCING ASCENT ASSOCIATED WITH AN UPPER VORT MAX
   POSITIONED FARTHER NWD...AND THE PRESENCE OF A WARM NOSE AROUND 2.5
   KM AGL LIKELY SUPPRESSING CONVECTION FOR MOST OF THE DAY.
   HOWEVER...SUSTAINED CONVERGENCE ALONG THE COLD FRONT...IN ADDITION
   TO THE ARRIVAL OF A WEAK UPPER SPEED MAX MOVING ACROSS E TX...APPEAR
   TO HAVE LOCALLY WEAKENED CINH...AND SHOULD CONTINUE TO SUPPORT AN
   INCREASE IN CONVECTIVE COVERAGE OVER THE NEXT FEW HRS.
   
   A MOIST WARM SECTOR /CHARACTERIZED BY MID-TO-UPPER-60S F DEW POINTS/
   IS CURRENTLY YIELDING ESTIMATED MLCAPE VALUES OF 2000-2500
   J/KG...ALTHOUGH INSTABILITY SHOULD GRADUALLY WANE OVER THE NEXT
   SEVERAL HRS WITH THE ONSET OF DIURNAL COOLING. MODERATELY STRONG AND
   NEARLY UNIDIRECTIONAL DEEP-LAYER FLOW ORIENTED PARALLEL TO THE FRONT
   WILL SUPPORT CELL INTERACTIONS AND PERHAPS SOME ORGANIZATION WITH
   THE STRONGEST STORMS. GIVEN THE UNCERTAINTY REGARDING THE DURATION
   AND MAGNITUDE OF THE THREAT...THE NEED FOR A WW IS STILL
   QUESTIONABLE...BUT TRENDS CONTINUE TO BE MONITORED.
   
   ..ROGERS/KERR.. 04/27/2013
   
   
   ATTN...WFO...JAN...LZK...SHV...
   
   LAT...LON   33769132 32029325 31769377 31489457 31609479 31989461
               33079314 33879230 33999199 33999150 33769132