SPC AC 241246

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0746 AM CDT THU APR 24 2014

   VALID 241300Z - 251200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS PORTIONS MID MS VALLEY AND
   MID-SOUTH REGION TO ARKLATEX...

   ...SUMMARY...
   SCATTERED STRONG TO SEVERE STORMS ARE EXPECTED TO FORM ALONG A
   CORRIDOR FROM SOUTHERN MISSOURI THROUGH ARKANSAS INTO NORTHERN
   LOUISIANA THURSDAY AFTERNOON...AND THEN SPREAD INTO WESTERN
   TENNESSEE...WESTERN KENTUCKY AND NORTHWEST MISSISSIPPI THURSDAY
   EVENING.  DAMAGING WINDS AND LARGE HAIL WILL BE THE PRIMARY THREATS.

   ...SYNOPSIS...
   IN MID-UPPER LEVELS...PROGRESSIVE WAVE TRAIN WILL CONTINUE TODAY
   OVER CONUS.  MAIN CONVECTIVE INFLUENCE WILL BE STG SHORTWAVE TROUGH
   INITIALLY LOCATED OVER CENTRAL/SRN HIGH PLAINS.  THIS PERTURBATION
   SHOULD REACH WRN PORTIONS MO/AR BY 00Z.  TROUGH SHOULD EXTEND ACROSS
   INDIANA...CENTRAL KY AND MID TN TO NRN AL BY 12Z. 

   RELATED SFC CYCLONE SHOULD EVOLVE FROM SERIES OF WEAK LOWS NOW
   LOCATED ALONG COLD FRONT FROM SWRN IA TO NRN
   OK...CONSOLIDATING/DEEPENING BY 00Z WHILE REACHING E-CENTRAL
   MO...THEN MOVING TO INDIANA AROUND END OF PERIOD.  COLD FRONT -- NOW
   OVER WRN OK AND ARCHING SWWD AND WWD ACROSS AREA BETWEEN LBB-MAF --
   SHOULD REACH S-CENTRAL MO...SWRN AR...E-CENTRAL TX AND S-CENTRAL TX
   BY 00Z...THEN BY 12Z...SRN INDIANA...NWRN AL...SERN LA AND NWRN
   GULF.  SEPARATE/PREFRONTAL/LOW-LEVEL BOUNDARY IS EVIDENT IN
   COMPOSITE RADAR IMAGERY AND SOME SFC DATA FROM PERMIAN BASIN OF W TX
   NEWD ACROSS NWRN FRINGES OF DFW METROPLEX TO S-CENTRAL AND E-CENTRAL
   OK AND ERN KS...MOVING SEWD 25-30 KT OVER TX AND EWD AT SIMILAR
   SPEEDS OVER OK/KS.  

   ...MID MS VALLEY AND MID-SOUTH REGION TO ARKLATEX...
   MULTIPLE ROUNDS OF TSTMS ARE EXPECTED OVER OUTLOOK AREA THIS PERIOD
   ALONG AND AHEAD OF SFC COLD FRONT...WITH MAJORITY OF SVR PROBABLE
   THIS AFTN INTO EARLY EVENING AS BANDS OF TSTMS SHIFT EWD ACROSS
   OUTLOOK AREA.  DAMAGING TSTM WIND...SPORADIC LARGE HAIL AND A FEW
   TORNADOES ARE POSSIBLE. 

   TSTM POTENTIAL BEGINS WITH ISOLATED/WEAK/ELEVATED ACTIVITY NOW OVER
   WRN PORTIONS MO/AR...LIKELY FOLLOWED BY MORE SUBSTANTIAL LINE OF
   TSTMS ALONG AFOREMENTIONED PREFRONTAL BOUNDARY.  LATTER ACTIVITY HAS
   ACCESS TO GREATER MOISTURE AND LIFT THAN CONVECTION FARTHER E...AND
   MAY PRODUCE ISOLATED HAIL NEAR SVR LEVELS THIS MORNING OVER ERN OK
   AND AR.  PORTIONS OF THIS ACTIVITY MAY ENCOUNTER FAVORABLY
   DESTABILIZING SFC-BASED PARCELS FROM MIDDAY INTO AFTN...FARTHER E
   NEAR MS RIVER.  ADDITIONAL DEVELOPMENT IS POSSIBLE IN BETWEEN THAT
   AND SFC COLD FRONT...AS WELL AS ALONG FRONT. 

   FIELD OF STG SYNOPTIC-SCALE ASCENT/DCVA AHEAD OF MID-UPPER TROUGH
   SHOULD OUTPACE SFC COLD FRONT TODAY AND BEGIN TO SPREAD OVER
   ADJOINING WARM SECTOR DURING AFTN PHASE OF SFC DIABATIC HEATING. 
   THIS WILL DESTABILIZE AIR MASS SFC AND ALOFT...CONTERMINOUS WITH
   FAVORABLE MOIST ADVECTION TO CONTRIBUTE FURTHER TO BUOYANCY. 
   BOUNDARY-LAYER MOISTURE IS FCST TO RETURN NEWD RAPIDLY ACROSS THIS
   REGION TODAY...ULTIMATELY YIELDING PREFRONTAL SFC DEW POINTS 50S F
   OVER PORTIONS MID-MS VALLEY REGION...IL...WRN KY AND MID TN...WITH
   60S F POSSIBLE OVER MOST OF AR...SRN MO...WRN TN AND MS.  

   ALTHOUGH CLOUDS/CONVECTION MAY LIMIT PACE OF DIABATIC HEATING TODAY
   OVER SRN MO AND AR...FCST SOUNDINGS SUGGEST CORRIDORS OF MLCAPE
   1000-1500 J/KG ARE POSSIBLE...DECREASING NWD ACROSS MO/IL.  BUOYANCY
   MAY INCREASE SWD OVER E TX AND LA...HOWEVER WEAKER LIFT AND LESSER
   DEEP SHEAR EACH CAST MORE UNCERTAINTY ONTO CONVECTIVE
   COVERAGE...DURATION AND ORGANIZATION S OF ARKLATEX AREA. 
   HENCE...GREATEST SVR PROBABILITIES ARE CONCENTRATED AS MAPPED.  SVR
   THREAT SHOULD DIMINISH LATE THIS EVENING AS TSTMS ENCOUNTER
   PROGRESSIVELY MORE STABLE BOUNDARY-LAYER AIR OVER CENTRAL KY...MID
   TN AND NRN AL.

   ..EDWARDS/ROGERS.. 04/24/2014

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