MESOSCALE DISCUSSION 0154
   NWS STORM PREDICTION CENTER NORMAN OK
   0132 PM CST FRI FEB 28 2014

   AREAS AFFECTED...SAN JOAQUIN VALLEY

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 281932Z - 282130Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...ISOLD STORMS WILL CONTINUE TO DEVELOP AND UNDERGO SOME
   STRENGTHENING THROUGH THE EARLY-MID AFTERNOON HOURS.  A SMALL HAIL
   THREAT AND/OR A STRONG WIND GUST MAY ACCOMPANY THE MOST INTENSE
   UPDRAFTS AND A CONDITIONAL WEAK/BRIEF TORNADO THREAT APPEARS TO BE
   SLOWLY INCREASING.

   DISCUSSION...THE LAST FEW HOURS OF VISIBLE SATELLITE IMAGERY HAVE
   SHOWN A SIZABLE BREAK IN CLOUD COVER ACROSS PORTIONS OF THE SAN
   JOAQUIN VALLEY AND THIS SURFACE DIABATIC HEATING HAS LOCALLY BOOSTED
   LOW LEVEL LAPSE RATES AND FURTHERED DESTABILIZATION.  19Z SURFACE
   OBSERVATIONS ACROSS THE VALLEY SHOW TEMPS RISING INTO THE MID 60S
   WITH LOW-MID 50S DEWPOINTS.  DESPITE THE MODEST SURFACE TEMPS...COOL
   TEMPS ALOFT /AOB -20 DEG C AT H5/ ASSOCIATED WITH THE MID-LEVEL LOW
   HAVE YIELDED MLCAPE VALUES IN THE 250-500 J/KG RANGE.  INCREASING
   LARGE-SCALE ASCENT ASSOCIATED WITH A MID-LEVEL VORTICITY LOBE
   ROUNDING THE BASE OF THE LARGER SCALE CIRCULATION IS FORECAST TO
   APPROACH PT. CONCEPTION BY LATE AFTERNOON...AND CONTINUE TO AT LEAST
   AGITATE CONVECTION AND LEAD TO INCREASING CONVECTIVE COVERAGE AND A
   FEW STORMS PERHAPS CAPABLE OF A MARGINAL HAIL/WIND THREAT.  TERRAIN
   CHANNELED BACKED LOW LEVEL FLOW WILL CONTINUE ENHANCE LOW LEVEL
   SHEAR AND MAY SUPPORT A CONDITIONAL THREAT FOR WEAK LOW LEVEL
   UPDRAFT ROTATION AND POSSIBLY A BRIEF/WEAK TORNADO.

   ..SMITH/MEAD.. 02/28/2014


   ATTN...WFO...VEF...HNX...

   LAT...LON   35151869 36512033 37412078 37672017 37301948 35581763
               35051808 35151869