SPC AC 251245

   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0745 AM CDT SAT MAY 25 2013

   VALID 251300Z - 261200Z

   ...THERE IS A SLGT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL AND NRN
   PLNS...

   ...SYNOPSIS...
   LITTLE CHANGE IN THE LARGE-SCALE PATTERN EXPECTED THIS PERIOD AS A
   RIDGE REMAINS STNRY OVER THE CNTRL PLNS/UPR MS VLY...BETWEEN SLOWLY
   PROGRESSIVE LOWS OVER THE PACIFIC NW AND SRN NEW ENGLAND. FARTHER
   S...A WEAKLY ORGANIZED MID/UPR-LVL TROUGH WILL DRIFT SLOWLY E/NE
   TOWARD THE ARKLATEX. AT THE SFC...A LEE TROUGH/DRYLINE SHOULD
   PERSIST OVER THE NRN/CNTRL HIGH PLNS AS A NW-SE WARM FRONT ADVANCES
   SLOWLY N ACROSS CNTRL/NRN PLNS. STRONG TO POSSIBLY SVR TSTM
   DEVELOPMENT WILL FOCUS ALONG BOTH THE LEE TROUGH AND FRONT LATER
   TODAY INTO SUN.

   ...CNTRL/NRN PLNS THIS AFTN/EVE...
   PERSISTENT SELY FLOW E OF LEE TROUGH WILL CONTINUE TO ADVECT LOW-LVL
   MOISTURE NWWD ACROSS THE NRN HALF OF THE PLNS TODAY...WITH SFC
   DEWPOINTS IN THE MID 50S F EXPECTED BY EVE IN FAR ERN MT/WRN
   ND...AND VALUES WELL INTO THE 60S LIKELY OVER WRN SD AND MUCH OF
   NEB. AT THE SAME TIME...MODERATE SWLY MID-LVL FLOW WILL MAINTAIN
   DEEP EML ACROSS REGION. COUPLED WITH DAYTIME HEATING...AFTN SBCAPE
   SHOULD RANGE FROM AROUND 1500 J/KG IN ERN MT/WRN ND TO NEAR 2500
   J/KG IN CNTRL NEB. 

   EML CAP LIKELY WILL DELAY SFC-BASED TSTM DEVELOPMENT UNTIL MID AFTN
   IN MOST AREAS. THE EARLIEST DEVELOPMENT MAY OCCUR OVER SE MT...NE
   WY...AND WRN SD /BLACK HILLS AREA/...WHERE LOW-LVL
   CONVERGENCE/UPSLOPE FLOW SHOULD BE GREATEST. THE STORMS SHOULD THEN
   MOVE/DEVELOP ESE INTO LOW-LVL MOIST AXIS OVER WRN PORTIONS OF THE
   LWR PLNS THIS EVE THROUGH EARLY SUN. 

   WHILE NO NOTEWORTHY UPR-LVL DISTURBANCE IS APPARENT IN STLT IMAGERY
   TO BOLSTER STORM STRENGTH/LONGEVITY...REGION WILL LIE BENEATH SRN
   FRINGE OF THE MAIN BELT OF THE WLYS...WITH AMPLE /35-40 KT/ WSWLY
   DEEP SHEAR FOR SUPERCELLS. VERY LARGE HAIL SHOULD BE THE MAIN SVR
   THREAT INITIALLY...ALTHOUGH TORNADOES ALSO MAY OCCUR. WITH TIME THE
   STORMS SHOULD MERGE INTO LINES/CLUSTERS THAT YIELD AN INCREASING
   RISK FOR DMGG WIND INTO THE EVE. THIS THREAT MAY PERSIST INTO EARLY
   SUN ALONG WARM FRONT OVER PARTS OF NEB AND SD...AIDED BY
   NOCTURNALLY-STRENGTHENED SLY LLJ. 

   ...SRN HIGH PLNS...
   MORE ISOLD TO WDLY SCTD STORMS SHOULD ONCE AGAIN FORM ALONG SRN HALF
   OF LEE TROUGH FROM WRN KS SSW THROUGH THE OK/TX PANHANDLES INTO ERN
   NM. THESE STORMS WILL EXIST IN COMPARATIVELY WEAK DEEP SHEAR AND
   MODEST MOISTURE. BUT STEEP LOW TO MID-LVL LAPSE RATES AND 25+ DEG
   LOW LEVEL TEMP-DEWPOINT SPREADS MAY YIELD A FEW STORMS WITH LARGE
   HAIL AND LOCALLY DMGG WIND.

   ...CNTRL/E TX TODAY/TNGT...
   SFC HEATING MAY PROMOTE THE DEVELOPMENT OF PERIODIC CLUSTERS OF
   STRONG TSTMS ALONG THE OUTER FRINGES OF SLOWLY-MOVING TX UPR SYSTEM
   TODAY...AND ADDITIONAL DEVELOPMENT CLOSER TO THE CENTER OF THE MAIN
   VORT ONCE AGAIN TNGT/EARLY SUN. WHILE DEEP SHEAR WILL REMAIN
   WEAK...SOME DEGREE OF LOW-LVL SPEED AND DIRECTIONAL SHEAR WILL
   PERSIST IN WARM/HUMID ENVIRONMENT ON THE E SIDE OF THE UPR SYSTEM.
   THIS SETUP MAY YIELD OCCASIONAL EMBEDDED AREAS OF LOW-LVL
   ROTATION...AND POSSIBLY A BRIEF TORNADO OR TWO. THE OVERALL SVR RISK
   DOES...HOWEVER...APPEAR TOO WEAK/UNFOCUSED TO WARRANT MORE THAN THE
   LOWEST CONDITIONAL PROBABILITIES ATTM.

   ..CORFIDI/MARSH.. 05/25/2013

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 1630Z