MESOSCALE PRECIPITATION DISCUSSION 0535
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1206 PM EDT SAT JUL 22 2017

AREAS AFFECTED...WEST TX, SOUTHWEST NM, & SOUTHEAST AZ

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

VALID 221605Z - 222205Z

SUMMARY...THUNDERSTORMS ARE EXPECTED TO DEVELOP IN THE
NEIGHBORHOOD OF TWO MCVs ACROSS PORTIONS OF THE SOUTHWEST.  HOURLY
RAIN RATES UP TO 2" WITH LOCAL AMOUNTS TO 3" ARE EXPECTED.

DISCUSSION...A PAIR OF MCVs LURK ACROSS SOUTHWEST NM AND JUST WEST
OF THE TX BIG BEND, SPOTTED ON EXPERIMENTAL GOES-16 0.86
MICRON/"VEGGIE BAND" IMAGERY.  RAP ANALYSES CAPTURE THE NM FEATURE
AT THE 700 HPA LEVEL.  CUMULIFORM CLOUDS ARE BUILDING AS CIN
ERODES ACROSS SOUTHWEST NM.  ML CAPE VALUES OF 500-1500 J/KG ARE
SEEN CURRENTLY ON SPC MESOANALYSES.  PRECIPITABLE WATER VALUES ARE
1-1.5" PER RECENT GPS INFORMATION.

A BUILDING RIDGE ACROSS THE GREAT BASIN IS EXPECTED TO PUSH THE NM
MCV SOUTHWARD DURING THE DAY TODAY. RELATIVELY SLOW CELL MOTIONS
ARE EXPECTED AS THE MEAN 850-400 HPA WIND IS LIGHT AND VARIABLE,
GENERALLY AROUND THE NM MCV.  MOSTLY CLEAR SKIES SHOULD ALLOW
1000-1500 J/KG OF ML CAPE TO BUILD ACROSS THE REGION, WHICH SHOULD
FOSTER THUNDERSTORMS WITH INCREASING RAIN RATES/COOLING CLOUD TOPS
INTO THIS AFTERNOON.  THE 06Z SSEO NEIGHBORHOOD PROBABILITIES OF
EXCEEDING THE THREE HOUR FLASH FLOOD GUIDANCE VALUES SHOW SPOTS OF
50%+ CHANCE OF EXCEEDANCE ACROSS SOUTHERN NM AND SOUTHEAST AZ
THROUGH 22Z.  THE AVAILABLE MOISTURE AND INSTABILITY FAVOR HOURLY
RAIN RATES UP TO 2".  THERE IS A SIGNAL WITHIN THE MESOSCALE
GUIDANCE FOR LOCAL AMOUNTS OF 3".  THIS COULD LEAD TO ISSUES IN
AREAS WHERE SOILS ARE PARTIALLY SATURATED FROM RECENT RAINS,
WITHIN EXISTING BURN SCARS, AND WITHIN RUGGED TERRAIN.

ROTH

ATTN...WFO...ABQ...EPZ...FGZ...MAF...PSR...TWC...

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

LAT...LON   34450955 34200713 33820589 33260520 32330456
            30970375 30600285 29850326 29400325 29240341
            29440363 29590441 30150482 30470499 30970573
            31560663 31660795 31310810 31220845 31230885
            31181090 31381162 31611170 32551109 33221113
            33971151 34411125