SPC AC 230552
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   1252 AM CDT THU MAY 23 2013
   
   VALID 231200Z - 241200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SRN HIGH
   PLAINS...
   
   ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE NERN
   STATES...
   
   ...SYNOPSIS...
   
   BLOCKING UPPER PATTERN WILL PERSIST THURSDAY. UPPER LOW OVER THE
   MID-UPPER MS VALLEY WILL ADVANCE THROUGH THE OH VALLEY...WHILE
   ANOTHER TROUGH AMPLIFIES SWD INTO THE GREAT LAKES REGION. CLOSED
   UPPER LOW OVER THE WRN STATES WILL DRIFT ONLY SLOWLY EWD...WHILE AN
   UPPER RIDGE BUILDS ACROSS THE CNTRL STATES. AT THE SFC A COLD FRONT
   WILL MOVE THROUGH ERN PORTIONS OF THE OH VALLEY INTO THE ERN STATES.
   TRAILING PORTION OF THIS BOUNDARY WILL LIFT NWD THROUGH NRN TX AND
   OK...WHILE A DRYLINE BECOMES ESTABLISHED ACROSS WRN TX.
   
   ...SRN HIGH PLAINS...
   
   CURRENT INDICATIONS ARE THAT ELEVATED STORMS WILL DEVELOP EARLY
   THURSDAY ACROSS NWRN TX INTO SWRN AND CNTRL OK WHERE THE NOCTURNAL
   LLJ WILL AUGMENT WARM ADVECTION AND ISENTROPIC ASCENT NORTH OF THE
   RETREATING BOUNDARY. RICHER LOW LEVEL MOISTURE WITH 60S DEWPOINTS
   WILL ADVECT NWWD THROUGH THE SRN PLAINS WARM SECTOR BENEATH STEEP
   LAPSE RATES. STRONG DIABATIC WARMING IS LIKELY SOUTH OF ONGOING
   CONVECTION ACROSS NWRN AND WRN TX...WHICH ALONG WITH INCREASING
   LOW-LEVEL MOISTURE WILL RESULT IN 2500-3000 J/KG MLCAPE DURING THE
   AFTERNOON. STORMS ARE EXPECTED TO DEVELOP BY MID-LATE AFTERNOON IN
   VICINITY OF THE DRYLINE/FRONT INTERSECTION OVER NWRN TX...AS WELL AS
   SOME DISTANCE SWD INTO THE HIGH PLAINS. RIDGING ALOFT WITH MODEST
   UPPER FLOW WILL TEMPER OVERALL SHEAR MAGNITUDES...BUT 30-35 KT
   EFFECTIVE SHEAR AND STRONG INSTABILITY WILL BE SUFFICIENT FOR A FEW
   SUPERCELLS WITH INITIAL STORMS THAT DEVELOP. PRIMARY THREAT WILL BE
   VERY LARGE HAIL. A TORNADO OR TWO MAY ALSO BE POSSIBLE ESPECIALLY
   DURING THE EARLY EVENING WHILE STORMS MAY STILL BE DISCRETE AND AS
   THE LLJ INCREASES. STORMS MAY EVOLVE INTO AN MCS AND PROPAGATE SEWD
   DURING THE EVENING WITH DAMAGING WIND BECOMING THE PRIMARY
   THREAT...BEFORE ACTIVITY WEAKENS TOWARD MID-LATE EVENING.
   
   ...NERN STATES...
   
   WIDESPREAD MULTILAYER CLOUDS ALONG CONVEYOR BELT WILL LIKELY LIMIT
   DIABATIC WARMING AND OVERALL DESTABILIZATION POTENTIAL ACROSS MUCH
   OF THE NERN STATES ON THURSDAY. HOWEVER...SOME CLOUD BREAKS WILL
   LIKELY OCCUR AND MODEST DIABATIC WARMING OF THE MOIST BOUNDARY LAYER
   WILL RESULT IN 500-1000 J/KG MLCAPE. BELT OF 35-40 KT MID-UPPER
   LEVEL FLOW ALONG ERN PERIPHERY OF THE UPPER TROUGH WILL EXIST IN
   WARM SECTOR RESULTING IN 30-40 KT EFFECTIVE SHEAR. STORMS MAY
   UNDERGO A GRADUAL INTENSIFICATION WITH ORGANIZED MULTICELLS CAPABLE
   OF PRODUCING MAINLY ISOLATED DAMAGING WIND. ANY SEVERE THREAT SHOULD
   DIMINISH BY EARLY EVENING.
   
   ..DIAL/GUYER.. 05/23/2013
   
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