MESOSCALE PRECIPITATION DISCUSSION 0573
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
929 AM EDT THU JUL 27 2017

AREAS AFFECTED...SOUTHEAST GA

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

VALID 271327Z - 271730Z

SUMMARY...A SMALL CLUSTER OF SLOW-MOVING SHOWERS AND THUNDERSTORMS
HAS BEEN DEVELOPING AND EXPANDING IN COVERAGE OVER THE LAST COUPLE
OF HOURS. SOME FURTHER ORGANIZATION IS EXPECTED OVER THE NEXT FEW
HOURS...AND VERY HEAVY RAINFALL AMOUNTS WILL BE POSSIBLE. EXPECT
SOME FLASH FLOODING AND/OR RUNOFF PROBLEMS TO BE POSSIBLE AS A
RESULT.

DISCUSSION...A RATHER COMPACT LOW TO MID LEVEL VORT
CENTER/CIRCULATION OVER SOUTHEAST GA HAS BECOME CONVECTIVELY
ACTIVE OVER THE TWO HOURS AND IS EXPECTED TO GAIN SOME ADDITIONAL
CONVECTIVE ORGANIZATION OVER THE NEXT FEW HOURS AS SOME TIGHTENING
OF THE LOW TO MID LEVEL VORTICITY AND STRONGER SURFACE CONVERGENCE
SETS UP. ALREADY THE LATEST RAP ANALYSIS SHOWS SHOWS A MOISTURE
CONVERGENCE MAXIMA OVER SOUTHEAST GA INLAND OF THE COAST AND
COINCIDENT WITH THE NORTHWEST FLANK OF WHAT APPEARS TO BE A WEAK
SURFACE LOW CENTER NEAR OR JUST OFFSHORE.

THE AIRMASS AROUND THIS CIRCULATION IS VERY MOIST WITH PWATS OF
2.2 TO 2.4 INCHES AND WITH PLENTY OF INSTABILITY POOLED ALONG AND
JUST OFFSHORE THAT IS EXPECTED TO BE TAPPED BY THE AFOREMENTIONED
ENERGY.

THE LATEST HRRR AND ESPECIALLY THE HRRRX GUIDANCE SUPPORT SOME
VERY HEAVY RAINFALL TOTALS THROUGH EARLY AFTERNOON...WITH LOCALLY
AS MUCH AS 4 TO 6+ INCHES POSSIBLE...WHICH SEEMS REASONABLE GIVEN
A LIKELIHOOD OF RAINFALL RATES PERHAPS EXCEEDING 3 INCHES/HR. SOME
RUNOFF PROBLEMS AND/OR FLASH FLOODING WILL BE POSSIBLE. WILL
CONTINUE TO MONITOR.

ORRISON

ATTN...WFO...CHS...JAX...

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

LAT...LON   32178176 32148117 31908094 31378123 30868139
            30738164 30958219 31288238 31748220