MESOSCALE PRECIPITATION DISCUSSION 0552
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
121 PM EDT FRI AUG 12 2016
 
AREAS AFFECTED...CENTRAL/SOUTHERN LA...SOUTHWEST MS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 121720Z - 122330Z
 
SUMMARY...DANGEROUS AND LIFE-THREATENING FLASH FLOODING/RUNOFF
FROM EXTREMELY HEAVY RAINFALL WILL CONTINUE THROUGH THIS AFTERNOON.

DISCUSSION...VERY INTENSE CONVECTIVE RAINFALL CONTINUES AROUND THE
SOUTHWEST FLANK OF A LOW TO MID LEVEL LOW CENTER OVER SOUTHWEST MS
WHICH CONTINUES TO SLOWLY DRIFT WEST. CLOUD TOPS HAVE WARMED EVER
SO SLIGHTLY OVER THE LAST COUPLE OF HOURS AS SEEN IN 1-MINUTE
GOES-14 IR ANIMATIONS...BUT CLOUD TOPS ARE STILL ABOUT -75C FROM
FAR SOUTHWEST MS INTO SOUTH-CENTRAL LA WHERE PROLIFIC RAINFALL HAS
BEEN OCCURRING THROUGHOUT THE MORNING HOURS.

THE CONVECTION REMAINS HIGHLY PERSISTENT WHILE FOCUSING WITHIN A
VERY MOIST/UNSTABLE AND CONFLUENT LOW LEVEL FLOW REGIME. PWATS ARE
VERY HIGH AND NEAR ALL-TIME RECORD LEVELS CURRENTLY OVER CENTRAL
AND SOUTHERN LA AS INDICATED BY THE 12Z LIX RAOB WHICH HAD A 2.78
INCH PW OF RECORD. LOW PRESSURE AT LEAST IN THE 850/500 MB LAYER
HAS BEEN SHOWING EVIDENCE OF STRENGTHENING THIS MORNING WHICH IS
HELPING TO FURTHER CONCENTRATE AND ORGANIZE THE CONVECTION WHILE
ALSO ENHANCING THE CONFLUENT LOW LEVEL FLOW AROUND THE SOUTHWEST
FLANK OF THE LOW CENTER.

THE 16Z HRRR/HRRRP GUIDANCE INDICATES THE POTENTIAL FOR AN
ADDITIONAL 4 TO 8 INCHES OF RAIN...WITH ISOLATED HEAVIER AMOUNTS
THROUGH LATE-AFTERNOON ACROSS PORTIONS OF CENTRAL AND SOUTHERN LA.
IN SOME CASES...THIS WILL BE ON TOP OF ALREADY EXTREMELY HEAVY
RAINFALL AMOUNTS THAT HAVE OCCURRED. DANGEROUS AND
LIFE-THREATENING FLASH FLOODING/RUNOFF WILL BE LIKELY AS A RESULT.

ORRISON

ATTN...WFO...JAN...LCH...LIX...SHV...

ATTN...RFC...LMRFC...WGRFC...

LAT...LON   31689210 31499149 31309061 31139026 30669006 
            30079033 29609092 29489155 29499197 29599272 
            29779319 30449358 31139340 31599281