MESOSCALE DISCUSSION 1518
   NWS STORM PREDICTION CENTER NORMAN OK
   0517 PM CDT THU JUL 25 2013

   AREAS AFFECTED...PORTIONS OF ARIZONA

   CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

   VALID 252217Z - 260045Z

   PROBABILITY OF WATCH ISSUANCE...20 PERCENT

   SUMMARY...A FEW SVR WIND GUSTS WILL BE POSSIBLE INTO THE EVENING
   HOURS...THOUGH THE ISSUANCE OF A WW IS UNLIKELY.

   DISCUSSION...SCATTERED CONVECTION THAT DEVELOPED ALONG THE HIGHER
   TERRAIN OF AZ IS CONGEALING INTO SMALLER MULTICELL CLUSTERS. THE
   PRESENCE OF 15-20-KT...MID-LEVEL ELY/S PER AREA VWP DATA WILL HAVE A
   TENDENCY TO STEER CONVECTION THAT DEVELOPED OVER THE SERN AZ
   MOUNTAINS TOWARD THE DESERT FLOORS OF S-CNTRL AZ. ONE STRONG
   CONVECTIVE CLUSTER MAY APPROACH THE PHOENIX AREA FROM THE E WITH
   STRONG OUTFLOW WINDS SURGING W OF THE PARENT CONVECTION. ADDITIONAL
   CONVECTION MAY DEVELOP ALONG THE LEADING EDGE OF THE OUTFLOW AND
   AROUND MORE ISOLATED HIGHER-TERRAIN AREAS IN S-CNTRL AZ.

   MEANWHILE...COLD POOLS ACCOMPANYING CONVECTION INVOF THE MOGOLLON
   RIM MAY DESCEND ALONG SRN SLOPES OF THE HIGHER TERRAIN IN CNTRL
   AZ...WITH CONVECTIVE REGENERATION OCCURRING ALONG THEIR LEADING
   EDGES INTO THE LOWER ELEVATIONS OF CNTRL/S-CNTRL AZ. THE AIR MASS
   ACROSS THIS AREA IS MODERATELY UNSTABLE...WHICH WILL CONTINUE TO
   SUPPORT A FEW VIGOROUS UPDRAFTS/DOWNDRAFTS INTO THE EVENING HOURS.
   RELATIVELY HIGH PW VALUES AROUND 1.5-1.9 INCHES PER GPS DATA WILL
   AID IN WATER LOADING PROCESSES AMIDST STEEP LOW-LEVEL LAPSE
   RATES/RELATIVELY HIGH DCAPE TO ENHANCE DOWNDRAFT STRENGTH. A FEW SVR
   WIND GUSTS WILL BE POSSIBLE INTO THE EVENING HOURS. HOWEVER...DEEP
   SHEAR ACROSS THE REGION IS WEAK PER AREA VWP DATA...WHICH WILL
   LIKELY PREVENT A MORE ORGANIZED SVR THREAT FROM EVOLVING.

   ..COHEN/CORFIDI.. 07/25/2013


   ATTN...WFO...TWC...FGZ...PSR...VEF...

   LAT...LON   31731191 32061305 33581376 34551391 35581379 35621288
               34551131 33111086 32271117 31731191