MESOSCALE PRECIPITATION DISCUSSION 0397
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
712 PM EDT WED JUN 29 2016
 
AREAS AFFECTED...SOUTHEAST AZ 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 292315Z - 300345Z
 
SUMMARY...EXISTING CONVECTION OVER SOUTHEAST AZ...AS WELL AS
CONVECTION APPROACHING FROM SONORA...COULD RESULT IN HOURLY
RAINFALL RATES NEAR 1.50 INCHES. THIS COULD RESULT IN FLASH
FLOODING/DEBRIS FLOWS THROUGH THE EARLY EVENING.

DISCUSSION...SCATTERED CONVECTION CONTINUES ACROSS SOUTHEAST
AZ...AS INSTABILITY (IN THE FORM OF 1000 J/KG MLCAPE) AND 1.25
INCH PRECIPITABLE WATER AIR (WHICH IS BETWEEN TWO AND THREE
STANDARD DEVIATIONS ABOVE THE MEAN) FEEDS THE ONGOING ACTIVITY.
THUS FAR...REGIONAL RADARS (INCLUDING KEMX AND KIWA) HAVE
INDICATED LOCAL HOURLY RAINFALL RATES NEAR 1.50 INCHES...BUT
HOURLY MESONET OBSERVATIONS HAVE BEEN CLOSER TO 0.50 INCHES.

THE LATEST RAP INDICATES THAT INSTABILITY (IN THE FORM OF MUCAPE
VALUES RISING TO BETWEEN 2000-3000 J/KG) SHOULD MAINTAIN ITSELF
THROUGH THE EVENING HOURS...AS WELL AS PRECIPITABLE WATER VALUES
NEAR 1.25 ON A PERSISTENT 15 KNOT 700 MB INFLOW. IN
ADDITION...ACTIVITY ACROSS THE BORDER IN SONORA COULD CROSS THE
BORDER INTO THE SOUTHEAST AZ LATE THIS AFTERNOON. 

IN ANY EVENT...THE ENVIRONMENT SHOULD BE SUFFICIENT TO SUPPORT
CONVECTION WITH LOCAL HOURLY RAINFALL RATES NEAR 1.50 INCHES
THROUGH AT LEAST 03Z. AFTER THAT TIME...CAM GUIDANCE LOSES THE
1.50 HOURLY RAINFALL SIGNAL...THOUGH THE INSTABILITY REMAINS IN
PLACE. THERE IS FAIRLY GOOD HIGH RESOLUTION MODEL AGREEMENT THAT
LOCAL 2-3 INCH RAINFALL AMOUNTS ARE POSSIBLE... ESPECIALLY WHERE
CELL MERGERS AND TRAINING OCCURS. THESE RAINFALL AMOUNTS COULD BE
ENOUGH TO PRODUCE FLASH FLOODING AND/OR DEBRIS FLOWS.

HAYES

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

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

LAT...LON   33461062 32930908 31320890 31261072 31731250 
            32361271