SPC AC 291957
   
   DAY 1 CONVECTIVE OUTLOOK  
   NWS STORM PREDICTION CENTER NORMAN OK
   0257 PM CDT FRI AUG 29 2008
   
   VALID 292000Z - 301200Z
   
   ...THERE IS A SLGT RISK OF SVR TSTMS THIS AFTERNOON AND TONIGHT OVER
   S-CNTRL/SWRN AZ...
   
   ...AZ/SERN CA...
   
   18Z TUS SOUNDING AND CURRENT SURFACE OBSERVATIONS INDICATE THAT AIR
   MASS IS SLOWLY DRYING OVER SERN AZ...PERHAPS DUE TO DOWNSLOPING
   EFFECTS OF DEEP-LAYER ELY WIND FIELDS.  HOWEVER...RUC OBJECTIVE
   FIELDS AND MODIFICATION OF 12Z PHOENIX SOUNDING FOR CURRENT
   CONDITIONS SUGGESTS THAT BOUNDARY LAYER OVER S-CNTRL/SWRN AZ IS
   ALREADY MODERATELY UNSTABLE WITH MLCAPES APPROACHING 2000-2500 J/KG.
   THERE IS SOME UNCERTAINTY AS TO WHETHER THE MODESTLY STRONG ELY
   WINDS ON THE LARGE-SCALE WILL OVERWHELM SMALLER-SCALE DIURNAL
   CIRCULATIONS...LIMITING THE NUMBER OF TSTMS THAT DEVELOP.  SHOULD
   THIS OCCUR...THE POTENTIAL FOR AN ORGANIZED TSTM COMPLEX CAPABLE OF
   A MORE WIDESPREAD WIND THREAT WOULD DIMINISH.
   
   HOWEVER...BASED ON THE OBSERVED THERMODYNAMIC AND KINEMATIC
   PARAMETERS...SETUP APPEARS FAVORABLE ENOUGH TO WARRANT INCLUSION OF
   HIGHER SEVERE PROBABILITIES AND A CATEGORICAL SLIGHT RISK.
   
   ...SRN OH VALLEY INTO THE SRN PLAINS...
   
   SYNOPTIC COLD FRONT EXTENDS FROM WRN OH SWWD THROUGH THE OZARK
   PLATEAU INTO THE TX PNHDL.  AN OUTFLOW BOUNDARY REMNANT FROM
   NOCTURNAL TSTM ACTIVITY PRECEDES COLD FRONT FROM NERN OK SEWD
   THROUGH CNTRL AR INTO THE MS DELTA.  THE COMBINATION OF STRONG
   DAYTIME HEATING AND DEWPOINTS IN THE 70S HAS RESULTED IN THE
   DEVELOPMENT OF A MODERATELY UNSTABLE AIR MASS THIS AFTERNOON WITH
   MLCAPES OF 1500-3000 J/KG FROM OK INTO THE LOWER MS VALLEY.
   
   TSTMS SHOULD CONTINUE TO INCREASE IN COVERAGE THIS AFTERNOON OWING
   TO SUSTAINED CONVERGENCE ALONG ABOVE-MENTIONED BOUNDARIES AND
   GROWING NUMBER OF STORM-SCALE COLD POOL INTERACTIONS.  VERTICAL
   SHEAR REMAINS QUITE WEAK...BUT THE DEGREE OF INSTABILITY SUGGESTS
   SOME POTENTIAL FOR A FEW STRONG PULSE-TYPE STORMS CAPABLE OF GUSTY
   WINDS AND PERHAPS SOME HAIL.
   
   ...S-CNTRL/SERN CO...
   
   AFTERNOON VISIBLE SATELLITE IMAGERY INDICATES DEEPENING CUMULUS
   DEVELOPMENT ALONG THE HIGHER TERRAIN OF CNTRL CO.  ELY LOW-LEVEL
   FLOW OVER THE ADJACENT HIGH PLAINS IS SERVING TO: 1) ENHANCE THE WWD
   FLUX OF AN INCREASINGLY MOIST AND UNSTABLE AIR MASS INTO AREA...AND
   2) PROMOTE OROGRAPHIC ASCENT ALONG THE FOOTHILLS.  AS MENTIONED IN
   PREVIOUS DISCUSSION...12Z GJT SOUNDING INDICATED THE PRESENCE OF
   SOME STRONGER HIGH-LEVEL FLOW...BUT IN GENERAL LOW TO MIDLEVEL SHEAR
   WILL REMAIN RATHER WEAK.  NONETHELESS...THE PRESENCE OF THE STEEP
   LAPSE RATES AND RESULTANT MODERATE CONVECTIVE INSTABILITY WILL BE
   SUPPORTIVE OF STRONGER STORMS CAPABLE OF HAIL AND LOCALLY DAMAGING
   WINDS.
   
   ..MEAD/KIS.. 08/29/2008
   
   CLICK TO GET WUUS01 PTSDY1 PRODUCT

   NOTE: THE NEXT DAY 1 OUTLOOK IS SCHEDULED BY 0100Z