MESOSCALE PRECIPITATION DISCUSSION 0242
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
420 PM EDT FRI AUG 01 2014
 
AREAS AFFECTED...PORTIONS OF SOUTHERN CO, NM, AND AZ 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 012019Z - 020219Z
 
SUMMARY...THUNDERSTORMS DEVELOPING ACROSS PORTIONS OF SOUTHERN CO,
NM, AND AZ COULD PRODUCE HOURLY RAIN RATES UP TO 1.5" ACROSS
RUGGED TERRAIN, SATURATED REGIONS OF NM, AND EVENTUALLY INTO THE
DESERT FLOORS OF AZ.  FLASH FLOODING IS CONSIDERED POSSIBLE.

DISCUSSION...SUNNY AREAS OF AZ AND NM HAVE BEGUN TO FIRE
THUNDERSTORM ACTIVITY, WITH SOUTHWEST AZ AND SOUTHEAST NM
ENSHROUDED BY CLOUDINESS SPONSORED BY TWO MCVS.  RECENT RAP
GUIDANCE SHOWS A BROAD LOW-LEVEL CIRCULATION AT 850 HPA AND 700
HPA NEAR THE AZ/NM BORDER.  PRECIPITABLE WATER VALUES IN THE
REGION ARE ~1.50", WITH LOWER VALUES OVER THE MOGOLLON RIM AND
HIGHER VALUES IN SOUTHERN AZ, NEAR THE 90TH PERCENTILE OR ALMOST
TWO STANDARD DEVIATIONS ABOVE NORMAL FOR EARLY AUGUST.  MIXED CAPE
VALUES ARE IN THE 1000-2000 J/KG RANGE IN AZ AND THE 500-1000 J/KG
RANGE NEAR THE CONTINENTAL DIVIDE IN NM.  

BOTH SETS OF CORFIDI VECTORS (BACKWARD AND FORWARD PROPAGATING)
ARE NEAR OR BELOW 10 KTS, IMPLYING SLOW CELL MOTION.  THERE IS A
STRONG SIGNAL IN THE 12Z SSEO NEIGHBORHOOD PROBABILITIES (50-70%)
FOR EXCESSIVE RAINFALL/FLASH FLOODING ACROSS PORTIONS OF
NORTHEAST, CENTRAL, AND SOUTHWEST NM, WITH A WEAKER SIGNAL (30%)
IN SOUTHEAST AZ AND THE MOGOLLON RIM WHERE THE MESOSCALE QPF
GUIDANCE TENDS TO BE TOO LOW.  AN UPPER HIGH OVER THE REGION
SHOULD PROMOTE AFTERNOON/EARLY EVENING CONVECTION, WITH CONVECTION
STARTING OUT IN THE MOUNTAINS AND MIGRATING TO THE DESERT FLOORS
OF AZ, PER RECENT RADAR IMAGERY AND COORDINATION WITH THE TWC
FORECAST OFFICE.  HOURLY RAINFALL RATES UP TO 1.5" AN HOUR ARE
POSSIBLE, WHICH LOCAL AMOUNTS OF 2-3" POSSIBLE WHERE CELLS MERGE
AND/OR TRAIN.

ROTH

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

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

LAT...LON   31200889 31281026 32051134 33301239 34241319 35211341
            36011298 36701136 36851006 37160884 37720787 37830558
            37650419 36890333 34060446 32620550 31730641 31720641
            31690789 31620805 31260809 31260808 31200889