ZCZC SPCSWOMCD ALL ACUS11 KWNS 281941 SPC MCD 281941 AZZ000-282215- MESOSCALE DISCUSSION 1422 NWS STORM PREDICTION CENTER NORMAN OK 0241 PM CDT THU JUL 28 2016 AREAS AFFECTED...PORTIONS OF CENTRAL/SOUTHERN/EASTERN ARIZONA CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY VALID 281941Z - 282215Z PROBABILITY OF WATCH ISSUANCE...20 PERCENT SUMMARY...PORTIONS OF ARIZONA ARE BEING MONITORED FOR AN INCREASE IN THE SVR-TSTM RISK THIS AFTERNOON...WITH THE SVR RISK CONTINUING INTO THE EVENING HOURS. PRESENT INDICATIONS ARE THAT WW ISSUANCE IS UNLIKELY...THOUGH CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED. DISCUSSION...CONVECTION CONTINUES TO BUILD OVER THE WHITE MOUNTAINS IN FAR E-CNTRL AZ...WITH ADDITIONAL CUMULUS DEVELOPMENT WWD ALONG THE MOGOLLON RIM...AND ACROSS MORE ISOLATED MOUNTAINS OVER FAR SRN AZ S/SE OF THE TUCSON AREA. THUS FAR...THE MOST VIGOROUS CONVECTIVE DEVELOPMENT HAS BEEN ACROSS THE WHITE MOUNTAINS...WHERE DIURNALLY ENHANCED OROGRAPHIC ASCENT SHOULD BE THE PRIMARY FOCUS FOR THE GREATEST COVERAGE OF SUBSEQUENT CONVECTIVE DEVELOPMENT. HOWEVER...AT LEAST ISOLATED TSTMS SHOULD FORM ELSEWHERE ACROSS THE REGION DURING THE NEXT FEW TO SEVERAL HOURS. PW AROUND 1.5-1.7 INCHES PER THE 12Z TUCSON AND PHOENIX RAOBS SUGGESTS THAT ADEQUATE MOISTURE IS IN PLACE FOR CONTINUED DIURNAL TSTM DEVELOPMENT....ESPECIALLY AS SFC DEWPOINTS HOLD IN THE 50S IN MANY AREAS. AS LOW-LEVEL LAPSE RATES CONTINUE STEEPENING ACROSS THE REGION...MLCAPE HAS INCREASED TO AROUND 1000 J/KG IN SOME LOCATIONS...AND ADDITIONAL DIURNAL GAINS IN BUOYANCY ARE ANTICIPATED WITH CONTINUED SFC HEATING. THE AFOREMENTIONED RAOBS ALSO SAMPLED A BELT OF MODESTLY ENHANCED ENELY/NELY MID-LEVEL FLOW -- AROUND 20-25 KT -- WITH THE STRONGEST MID-LEVEL FLOW AT TUCSON. THIS WAS IN ASSOCIATION WITH A MODESTLY ENHANCED MID-LEVEL HEIGHT GRADIENT -- BETWEEN THE SRN RIM OF A PROMINENT ANTICYCLONE OVER THE CNTRL GREAT BASIN/SWRN CONUS AND AN MCV MOVING ACROSS THE GULF OF CALIFORNIA TO THE BAJA CALIFORNIA PENINSULA. WHILE THE DEARTH OF SALIENT UPSHEAR PERTURBATIONS AND RELATED ASCENT DETRACT CONFIDENCE IN PARTICULARLY WIDESPREAD CONVECTIVE COVERAGE EVOLVING...SUFFICIENT MID-LEVEL FLOW TRAILING FROM THE N SIDE OF THE MCV...AND SOME MODEST INFLUX OF MID-LEVEL DRY AIR FROM THE E...SUGGEST THAT SEMI-ORGANIZED CONVECTIVE CLUSTERS MAY EVOLVE FROM ONGOING INCIPIENT CONVECTION -- THROUGH THE LATE AFTERNOON AND INTO THE EVENING HOURS. LARGE DCAPE -- AROUND 1200-1700 J/KG -- COUPLED WITH THE MODESTLY ENHANCED MID-LEVEL FLOW ENHANCING DEEP SHEAR -- SUGGESTS THAT COLD-POOL CONSOLIDATION COULD OCCUR FROM CONVECTION SPREADING WSWWD OFF THE HIGHER TERRAIN AND ACROSS THE DESERT FLOOR BY LATE AFTERNOON/EVENING. ISOLATED SVR WIND GUSTS MAY ACCOMPANY THIS ACTIVITY -- PARTICULARLY IF UPSCALE CONVECTIVE GROWTH WERE TO LOCALLY OCCUR FROM CONVECTION MOVING OFF THE WHITE MOUNTAINS. ISOLATED MARGINALLY SVR HAIL CANNOT BE RULED OUT. THE GREATEST POTENTIAL FOR ISOLATED SVR TSTMS WILL BE ACROSS SRN PARTS OF CNTRL AZ...PERHAPS INCLUDING AREAS NEAR PHOENIX...BY EVENING. FURTHERMORE...BLOWING DUST GREATLY REDUCING VISIBILITY WILL BE OF CONCERN WITH THIS ACTIVITY. HOWEVER...THE OVERALL LACK OF LARGE-SCALE ASCENT DETRACTS CONFIDENCE IN A MORE-THAN-ISOLATED SVR RISK EVOLVING AT THIS TIME. REGARDLESS...CONVECTIVE TRENDS WILL CONTINUE TO BE MONITORED. ..COHEN/DIAL.. 07/28/2016 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...TWC...FGZ...PSR... LAT...LON 31441113 32271216 33591228 34331123 33880979 33130915 31670938 31441113 NNNN