MESOSCALE PRECIPITATION DISCUSSION 0650
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
511 AM EDT WED SEP 07 2016
 
AREAS AFFECTED...SOUTHEAST AZ...EXT SOUTHWEST NM 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 070911Z - 071511Z
 
SUMMARY...APPROACH OF TROPICAL CYCLONE NEWTON MODERATE RAINS WITH
EMBEDDED CONVECTIVE ELEMENTS MAY POSE FLOODING CONCERNS.

DISCUSSION...GOES IR/WV INDICATES INNER CORE OF TC NEWTON IS
MAINTAINING SCATTERED SHALLOW CONVECTIVE TOWERS...WITH BROAD
ANTICYCLONIC ENVELOPE WITH STRONG SW-NE 100 KT JET PROVIDING
CONTINUED BROAD LARGE SCALE ASCENT ACROSS MUCH OF SE AZ.  GENERAL
TIMING SEEMS ON PAR WITH NUMEROUS HI-RES MODELS INCLUDING THE
RECENT FEW HRRR RUNS, THE 00Z ARW/NMMB AND GEM REGIONAL STARTING
TO PRESENT THE NORTHERN INNER CORE BANDS REACHING THE S AZ DESERTS
BY 12Z...WITH STRONG 40-50 850MB MST FLUX TO SUPPORT TPWS NEARING
2.0" AND NEARLY SATURATED PROFILES...THOUGH MUCH OF ASCENT WILL BE
DYNAMICALLY DRIVEN DUE TO MASS CONVERGENCE IN THE LOW LEVELS AND
STRONG DIVERGENCE ALOFT...NARROW SKINNY PROFILES MAY SUPPORT WEAK
CAPES IN THE 100-250 J/KG RANGE FOR SOME EMBEDDED CONVECTIVE
ELEMENTS LOCALLY RAISING RAIN RATES FROM .25-.5"/HR UP TO 1.0"/HR
POSSIBLY. OROGRAPHIC ASCENT IN FAVORED ZONES SHOULD CONTRIBUTE TO
RATES LOCALLY AS WELL...INCREASING TOTALS IN FAVORED TERRAIN. 

WITH TIME LOW TO MID-LEVEL FLOW IS ALSO BECOMING LOCALLY
CONFLUENT/CONVERGENT AS NEWTON LIFTS NORTHWEST OF THE SUBTROPICAL
RIDGE AXIS THAT EXTENDS ACROSS NORTHERN MEXICO BEFORE FLOW RETURNS
AS SWLY FLOW AHEAD OF THE WESTERN US TROUGHING.  AS SUCH BANDS
WILL BECOMING CONFLUENT INTO SW-NE DEFORMATION ZONE THAT SHOULD
SET UP FROM CENTRAL PIMA COUNTY TOWARD CATRON COUNTY NM.  THIS
SHOULD FOCUS GREATEST THREAT/TOTALS 1-3" (LOCALLY HIGHER) ACROSS E
PIMA/SANTA CRUZ AND W COCHISE COUNTY THROUGH 15Z. 

ALONG THE AZ/NM BORDER...OUTER BAND OF NEWTON IS LIFTING NORTH AND
IS ORIENTED NNW TO SSE FROM EASTERN COCHISE NEAR/ALONG THE
SONORA/CHIHUAHUA BORDER.  THIS APPEARS TO BE A DEMARCATION BETWEEN
DRIER LOW LEVEL MEXICAN PLATEAU AIR (SUB 1.5" TPWS) AND THE DEEP
TROPICAL AIR (OVER 1.75") AS WELL. INCREASED MST CONVERGENCE ALONG
THIS BAND ALONG WITH MLCAPES IN THE 250 J/KG RANGE PER RAP
ANALYSIS APPEAR TO ENHANCING SOME DEEPER CONVECTION IN THE NEAR
TERM.  CELL MOTIONS TOWARD THE N AND NNW ALONG THIS BAND SUPPORT
SOME TRAINING AND INDICATES A CORRIDOR OF ENHANCED RAINFALL TOTALS
UP TO 1-2" POSSIBLE POTENTIALLY PRODUCING ISOLATED FLOODING
CONCERNS THROUGH 15Z HERE AS WELL.

GALLINA

ATTN...WFO...EPZ...TWC...

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

LAT...LON   33130948 32390855 31300869 31200920 31241109 
            31491207 32001218 32801080 33081014