MESOSCALE PRECIPITATION DISCUSSION 0462
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
645 PM EDT SUN JUL 15 2018

AREAS AFFECTED...SOUTHERN UT...NORTHERN/CENTRAL AZ...WESTERN NM

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 152245Z - 160400Z

SUMMARY...MONSOONAL SHOWERS AND THUNDERSTORMS WILL CONTINUE
THROUGH THE EVENING HOURS. FLASH FLOODING WILL REMAIN LIKELY.

DISCUSSION...THE LATEST RADAR AND SATELLITE IMAGERY SHOWS NUMEROUS
SHOWERS AND THUNDERSTORMS ACROSS THE SOUTHWEST U.S. IN ASSOCIATION
WITH THE MONSOON PATTERN.

ROBUST DIURNAL HEATING/SURFACE-BASED INSTABILITY HAS CONTRIBUTED
TO MLCAPE VALUES OF 1000 TO 2000 J/KG AND THIS COUPLED WITH
OROGRAPHICS...SMALL SCALE OUTFLOW/MESOSCALE BOUNDARIES AND RATHER
DIFFLUENT FLOW ALOFT WILL CONTINUE TO MAINTAIN THE CONVECTIVE
THREAT THROUGH THE EVENING HOURS. IN FACT...THE LATEST GOES-16 DAY
CONVECTION RGB IMAGERY IS SHOWING AN EXPANSION OF VERY STRONG
CONVECTIVE FORCING AND ASSOCIATED UPDRAFTS WITH AN EMPHASIS ON
WEST-CENTRAL AZ INCLUDING YAVAPAI COUNTY.

PWATS ACROSS THE REGION REMAIN ANOMALOUSLY HIGH WITH VALUES 2 TO
2.5 STANDARD DEVIATIONS ABOVE NORMAL...AND MOISTURE QUITE
PRONOUNCED IN THE 500/300 MB LAYER OF THE COLUMN. THIS WILL AGAIN
FAVOR EFFICIENT RAINFALL PROCESSES FOR ENHANCED RAINFALL RATES
THAT COULD EXCEED 2 INCHES/HR.

THE CONVECTION SHOULD BEGIN TO EXHAUST THE AVAILABLE INSTABILITY
BY AROUND 03Z AND THIS WILL LEAD TO A GRADUAL DECREASE IN
CONVECTIVE COVERAGE AND INTENSITY...BUT UNTIL THEN...EXPECT
ADDITIONAL HEAVY RAINFALL AMOUNTS OF AS MUCH AS 3 TO 4 INCHES WITH
THE STRONGEST CONVECTIVE CORES. THE GREATEST POTENTIAL WILL TEND
TO BE OVER CENTRAL AND NORTHERN AZ...BUT ADDITIONAL HEAVY RAINS
ARE EXPECTED UP OVER SOUTHERN UT AND WESTERN NM AS WELL.

FLASH FLOODING WILL REMAIN LIKELY GOING THROUGH THE EVENING...WITH
AGAIN THE BIGGEST CONCERNS INVOLVING SLOT-CANYONS...WASHES AND
BURN SCARS.

ORRISON

ATTN...WFO...ABQ...EPZ...FGZ...GJT...PSR...SLC...TWC...VEF...

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

LAT...LON   38501193 37961120 37241039 36520895 35240805
            33760800 32960880 32931020 33151122 33401231
            33971351 34321393 35171433 36251403 37061352
            38081298