MESOSCALE PRECIPITATION DISCUSSION 0427
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
855 PM EDT SAT JUL 01 2017

AREAS AFFECTED...CENTRAL MS...CENTRAL AL

CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE

VALID 020050Z - 020345Z

SUMMARY...SLOW-MOVING THUNDERSTORMS WITH INTENSE RAINFALL RATES
WILL CONTINUE TO SETTLE SOUTH AND GRADUALLY WEAKEN LATER THIS
EVENING.

DISCUSSION...VERY LATE-DAY EXPERIMENTAL GOES-16 VISIBLE SAT
IMAGERY SHOWS A CONVECTIVELY ENHANCED OUTFLOW BOUNDARY SETTLING
SOUTH-SOUTHEAST ACROSS AREAS OF CENTRAL MS TO CENTRAL AL. THIS
CONTINUES TO INTERACT WITH A MODERATELY UNSTABLE AND VERY MOIST
AIRMASS AND IS PRODUCE AN EXTENSIVE AREA OF HEAVY SHOWERS AND
THUNDERSTORMS.

THE CONVECTIVE CLOUD TOPS HAVE CONTINUED TO COOL A BIT OVER THE
LAST HOUR...AND A FEW WELL-DEFINED OVERSHOOTING TOPS.
HOWEVER...THE AVAILABLE INSTABILITY WHICH IS ABOUT 1500 J/KG OF
MLCAPE WILL BECOME INCREASINGLY EXHAUSTED BY LATE EVENING...AND
WITH A LACK OF ANY STRONGER LARGE SCALE FORCING/ASCENT IN PLACE TO
SUSTAIN CONVECTION...IT IS EXPECTED THAT CONVECTION WILL BEGIN TO
WEAKEN SUBSTANTIALLY BY LATE EVENING.

HOWEVER...OVER THE NEXT 2 TO 3 HOURS...THERE MAY BE SOME
ADDITIONAL INTENSE AND FAIRLY SLOW-MOVING CELLS WITH A COUPLE OF
OVERSHOOTING TOPS THAT MAY PRODUCE RAINFALL RATES UPWARDS OF 2.5
INCHES/HR GIVEN THE HIGHER PWAT ENVIRONMENT. SOME RUNOFF PROBLEMS
AND ISOLATED FLASH FLOODING WILL REMAIN POSSIBLE AS A RESULT
BEFORE CONDITIONS IMPROVE.

ORRISON

ATTN...WFO...BMX...JAN...MOB...

ATTN...RFC...LMRFC...SERFC...

LAT...LON   32658669 32458622 32018636 31708680 31558746
            31458838 31468914 31578957 31748989 32088997
            32348967 32558858 32658758