MESOSCALE DISCUSSION 0358
   NWS STORM PREDICTION CENTER NORMAN OK
   0459 PM CDT SUN MAR 31 2013
   
   AREAS AFFECTED...A LARGE PART OF CNTRL/NRN CA
   
   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 
   
   VALID 312159Z - 010000Z
   
   PROBABILITY OF WATCH ISSUANCE...5 PERCENT
   
   SUMMARY...THUNDERSTORMS WILL CONTINUE TO INCREASE IN COVERAGE ACROSS
   CNTRL/NRN CA THROUGH THE AFTERNOON. SMALL HAIL WILL BE POSSIBLE WITH
   THIS ACTIVITY...AND ONE OR TWO STORMS MAY PRODUCE MARGINALLY SVR
   HAIL. A WW WILL NOT BE NEEDED.
   
   DISCUSSION...DIURNAL DIABATIC HEATING WITHIN THE BOUNDARY
   LAYER...BENEATH COOLING MID-LEVEL TEMPERATURES PRECEDING A MID-LEVEL
   VORT MAX APPROACHING THE CNTRL CA COAST...IS YIELDING MARGINAL
   INSTABILITY. MODIFIED FORECAST SOUNDINGS TO ACCOUNT FOR CURRENT SFC
   OBSERVATIONS SUGGEST THAT MLCAPE VALUES OF 250-800 J/KG ARE COMMON
   ACROSS THE AREA. THE GREATEST INSTABILITY IS OVER THE SAN JOAQUIN
   AND SACRAMENTO VALLEYS...WHERE INSOLATION HAS BEEN MAXIMIZED WITH
   SFC TEMPERATURES HAVING CLIMBED INTO THE UPPER 60S AND LOWER 70S.
   OROGRAPHIC ASCENT AUGMENTED BY DCVA LEADING THE MID-LEVEL VORT MAX
   CONTINUES SUPPORTING CONVECTIVE DEVELOPMENT OVER THE COASTAL
   RANGES...AND SOME OF THIS ACTIVITY IS BEGINNING TO SPREAD OVER THE
   ADJACENT LOWER ELEVATIONS ACROSS THE CNTRL CA INTERIOR.
   
   AS THE DCVA MAKES ADDITIONAL PROGRESS INLAND DURING THE NEXT SEVERAL
   HOURS...THUNDERSTORMS WILL LIKELY INCREASE IN COVERAGE. THE
   AFOREMENTIONED DEGREE OF BUOYANCY AMID 500-MB TEMPERATURES FROM -25C
   TO -20C WILL LIKELY YIELD A THREAT FOR SMALL HAIL. ONE OR TWO OF THE
   STRONGEST STORMS COULD ALSO PRODUCE MARGINALLY SVR HAIL...ESPECIALLY
   INVOF THE COLDEST MID-LEVEL TEMPERATURES AND STRONGEST
   BOUNDARY-LAYER BUOYANCY -- FROM THE CNTRL CA COASTAL RANGES TO THE
   ADJACENT CNTRL CA VALLEY. HOWEVER...WITH AOB 25 KT OF DEEP SHEAR AND
   WITH WEAK LOW-LEVEL FLOW DEPICTED BY REGIONAL VWP
   DATA...THUNDERSTORMS WILL LIKELY LACK ANY SUBSTANTIAL
   ORGANIZATION/PERSISTENCE...GREATLY LIMITING ANY SVR THREAT. STORMS
   SHOULD WEAKEN AFTER SUNSET AS THE BOUNDARY LAYER STABILIZES.
   
   ..COHEN/MEAD.. 03/31/2013
   
   
   ATTN...WFO...HNX...STO...MTR...EKA...
   
   LAT...LON   39192375 39792394 40162414 40552359 40562251 39272076
               37411901 36861871 36071928 35792066 36192164 36772202
               37772253 38582331 39192375