MESOSCALE PRECIPITATION DISCUSSION 0443
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1138 PM EDT TUE AUG 11 2015
 
AREAS AFFECTED...AZ 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 120330Z - 120730Z
 
SUMMARY...NUMEROUS SHOWERS AND THUNDERSTORMS WILL CONTINUE OVER
THE NEXT FEW HOURS. THE POTENTIAL FOR FLASH FLOODING REMAINS.

DISCUSSION...CLUSTERS OF COLD-TOPPED CONVECTION CONTINUE ACROSS
SOUTHEAST AZ AT THIS TIME...WITH THE ACTIVITY LIFTING NORTHWEST
WITHIN DEEPER LAYER SOUTHEAST FLOW AROUND THE SOUTHWEST FLANK OF A
MID LEVEL RIDGE AXIS OVER THE SOUTHERN HIGH PLAINS. THE CONVECTION
IS BEING AIDED BY THE PRESENCE OF N/S AXIS OF AT LEAST MODEST
INSTABILITY...BUT ESPECIALLY WITH A WELL-DEFINED CHANNEL OF DEEPER
LAYER MOISTURE AS INDICATED BY THE CIRA LAYERED PWAT PRODUCT.
GOES-SOUNDER PWATS RUNNING AS HIGH 1.5 TO 1.75 INCHES ARE ALSO
NOTED OVER THE REGION.

SATELLITE IMAGERY SHOWS A FAIRLY WELL-DEFINED VORT CENTER OVER
SOUTHWEST AZ CURRENTLY AS WELL...AND THIS IS HELPING TO
CONCENTRATE THE MOISTURE TRANSPORT UP ACROSS SOUTHEAST AND INTO
CENTRAL AZ WHILE ALSO PROVIDING SOME LARGER SCALE FORCING/ASCENT
ALOFT TO COMPLEMENT THE OTHERWISE FAVORABLE THERMODYNAMIC
ENVIRONMENT.

OVER THE NEXT FEW HOURS...THE CONVECTION WILL CONTINUE TO PERSIST
OVER PORTIONS OF SOUTHEAST AZ...BUT WILL BE LIFTING NORTHWEST UP
ACROSS CENTRAL AZ AND INTO THE MOGOLLON RIM AREA WHERE OROGRAPHICS
WILL HELP TO ENHANCE FORCING FURTHER...AND THUS YIELD HEAVIER
RAINFALL RATES. EXPECT LOCALLY AS MUCH AS 1 TO 2 INCHES/HR...WHICH
MAY ALSO BE ENHANCED FURTHER BY A FEW CELL MERGERS AND A COUPLE OF
OVERSHOOTING TOPS. THE HIRES MODELS DO NOT APPEAR TO BE HANDING
THE ONGOING CONVECTION TOO WELL AS CLOUD TOPS HAVE BEEN CONTINUING
TO COOL...WHEREAS THE HIRES MODELS ARE SUGGESTING THAT CONVECTION
SHOULD ALREADY BE WEAKENING.

THE THREAT FOR FLASH FLOODING WILL CONTINUE OVER THE NEXT FEW
HOURS...BEFORE THEN DIMINISHING LATER IN THE EVENING AS THE
AVAILABLE INSTABILITY GRADUALLY BECOMES EXHAUSTED AND CONVECTION
FINALLY WEAKENS.

ORRISON

ATTN...WFO...FGZ...PSR...TWC...VEF...

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

LAT...LON   36801095 35890999 34630940 33820920 32320915 
            31590954 31331047 31671131 32641223 33711292 
            35061338 36171315 36771235 
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