MESOSCALE PRECIPITATION DISCUSSION 0801
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
654 PM EDT SUN SEP 10 2017

AREAS AFFECTED...NORTHERN/CENTRAL AZ

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 102250Z - 110300Z

SUMMARY...SCATTERED CLUSTERS OF HEAVY SHOWERS AND THUNDERSTORMS
ARE EXPECTED OVER THE NEXT FEW HOURS. SOME FLASH FLOODING WILL BE
POSSIBLE CONSIDERING THE SLOW CELL MOTION.

DISCUSSION...STRONG DIURNAL HEATING AND RELATIVELY FAVORABLE
MOISTURE PROFILES ARE HELPING TO FOSTER CONVECTIVE INITIATION OVER
THE OROGRAPHICALLY FAVORED MOGOLLON RIM. NON-OPERATIONAL GOES-16
0.64 MICRON/VIS IMAGERY SHOWS AGITATED CU/TCU OVER THE REGION WITH
RADAR CONFIRMING SOME LOCALLY HEAVY CONVECTIVE CORES.

SOME ADDITIONAL INCREASE IN CONVECTIVE COVERAGE AND ORGANIZATION
IS EXPECTED OVER THE NEXT COUPLE OF HOURS AS ADDITIONAL DIURNALLY
ENHANCED INSTABILITY FOCUSES OVER THE REGION. SOME BRIEF
CELL-MERGER ACTIVITY IS ANTICIPATED AS WELL WHICH WILL FOSTER SOME
LOCALLY ENHANCED RAINFALL RATES THAT COULD APPROACH 1.5 INCHES/HR.

THE HIRES MODELS SUPPORTED BY THE 12Z ARW AND 12Z NMMB SUPPORT
SOME 1 TO 2 INCH RAINFALL AMOUNTS THROUGH ABOUT 03Z...BUT SOME
ISOLATED HEAVIER TOTALS CANNOT BE RULED OUT GIVEN THE SLOW CELL
MOTION AND FAVORABLE OROGRAPHIC SET-UP. SOME FLASH FLOODING WILL
BE POSSIBLE AS A RESULT OVER THE HIGHER TERRAIN AND NEAR ANY
SLOT-CANYONS OR DRY WASHES.

ORRISON

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

ATTN...RFC...CBRFC...

LAT...LON   36951267 36861218 35791177 35171132 34731070
            34181039 33801076 33771153 33921212 34261290
            34701342 35371364 35931325 36221296