MESOSCALE PRECIPITATION DISCUSSION 0452
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
705 PM EDT SAT JUL 14 2018

AREAS AFFECTED...FAR SOUTHEAST NV...SOUTHERN UT..FAR SOUTHWEST
CO....AZ...WESTERN NM

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

VALID 142305Z - 150405Z

SUMMARY...ADDITIONAL SLOW-MOVING SHOWERS AND THUNDERSTORMS WILL
CONTINUE TO FOSTER A LIKELIHOOD OF FLASH FLOODING THROUGH THE
EVENING HOURS.

DISCUSSION...THE AFTERNOON GOES-16 DAY CONVECTION RGB SATELLITE
IMAGERY SHOWS NUMEROUS CLUSTERS OF VIGOROUS CONVECTION WITH ROBUST
COLD-TOPPED UPDRAFTS IMPACTING AREAS OF SOUTHEAST NV...SOUTHERN
UT...SOUTHWEST CO AND SOUTH DOWN ACROSS A LARGE AREA OF AZ AND NM.
THE CONVECTION IS IS BEING HIGHLY FACILITATED BY AN ANOMALOUSLY
MOIST AND UNSTABLE ENVIRONMENT ASSOCIATED WITH THE MONSOON PATTERN
ACROSS THE GREATER SOUTHWEST U.S. THERE CONTINUES TO ALSO BE THE
PRESENCE OF AN MCV OVER CENTRAL AZ TO THE SOUTH OF THE MOGOLLON
RIM WHICH IS PROVIDING SOME SMALLER SCALE FORCING FOR CONVECTION
IN CONJUNCTION WITH TERRAIN-DRIVEN OROGRAPHICS WHICH HAVE BEEN A
NOTABLE FOCUS THROUGH THE AFTERNOON SO FAR.

PWATS ACROSS THE REGION REMAIN AS MUCH AS 2 TO 3 STANDARD
DEVIATIONS ABOVE NORMAL AND THIS WILL CONTINUE TO FAVOR A HIGHLY
EFFICIENT ENVIRONMENT FOR ENHANCED RAINFALL RATES. RAINFALL RATES
HAVE BEEN LOCALLY EXCEEDING 2 INCHES/HR...AND THIS SHOULD REMAIN
THE CASE GOING THROUGH THE EVENING HOURS AS CONVECTION CONTINUES
TO EXPAND IN COVERAGE AND GRADUALLY EXHAUST WHAT IS A MODERATELY
UNSTABLE BOUNDARY LAYER AT THIS TIME GIVEN MLCAPE VALUES OF AS
HIGH AS 1500 J/KG. ADDITIONAL RAINFALL AMOUNTS MAY LOCALLY REACH
AS MUCH AS 3 TO 4 INCHES WITHIN THE STRONGER CONVECTIVE
CORES...AND ESPECIALLY WHERE OVERSHOOTING TOP ACTIVITY OCCURS.

FLASH FLOODING WILL REMAIN LIKELY...WITH PARTICULAR FOCUS AGAIN ON
AREA SLOT CANYONS...DRY WASHES AND BURN SCARS. WILL CONTINUE TO
MONITOR.

ORRISON

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

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

LAT...LON   39001226 38861123 38501004 38250895 37740840
            36540843 35830817 35370728 35220671 34800600
            33290607 31880728 31490895 31840966 32791071
            33361222 33621363 34771444 36861459 38221416
            38941296