MESOSCALE PRECIPITATION DISCUSSION 0580...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
725 AM EDT FRI JUL 28 2017

CORRECTED FOR ADJUSTED RAINFALL AMOUNTS

AREAS AFFECTED...SOUTHERN TN...NORTHERN AL

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

VALID 281105Z - 281705Z

SUMMARY...HEAVY SHOWERS AND THUNDERSTORMS WITH SOME BACKBUILDING
AND TRAINING OF CELLS WILL LIKELY CONTINUE OVER THE NEXT SEVERAL
HOURS. FLASH FLOODING IS POSSIBLE.

DISCUSSION...EARLY MORNING EXPERIMENTAL GOES-16 10.3 MICRON/IR
DATA SHOWS SOME IMPRESSIVELY COLD CONVECTIVE TOPS THAT HAVE SET UP
OVER AREAS OF SOUTH-CENTRAL TN OVER THE LAST HOUR. DESPITE
RELATIVELY MODEST INSTABILITY PARAMETERS...THE CONVECTION IS
FOCUSING IN AN AREA WHERE THERE IS A MOISTURE CONVERGENCE MAXIMA
BASED ON THE LATEST RAP ANALYSIS AND IS ALSO WITHIN AN
INCREASINGLY DIFFLUENT FLOW PATTERN ALOFT. THE LOW LEVEL FLOW
ACROSS THE REGION IS ALSO BECOMING INCREASINGLY CONFLUENT OUT
AHEAD OF A COLD FRONT.

PWATS ACROSS THE REGION ARE QUITE HIGH AND GENERALLY AROUND 2.25
INCHES. THE 09Z CIRA-LPW PRODUCT SHOWS A NOTABLY CONCENTRATED POOL
OF MOISTURE IN THE 700/300 MB LAYER AND THIS WILL YIELD HIGHLY
EFFICIENT RAINFALL PROCESSES FOR ENHANCED RAINFALL RATES...AND
ESPECIALLY WITH SUCH COLD CONVECTIVE TOPS DEVELOPING IN THIS
ENVIRONMENT.

RAINFALL RATES OF TO 2.5 TO 3 INCHES/HR CANNOT BE RULED OUT...AND
THE LATEST HIRES MODEL CONSENSUS SUGGESTS SOME ADDITIONAL
CONVECTIVE ORGANIZATION OVER THE NEXT SEVERAL HOURS AS ADDITIONAL
LARGER SCALE FORCING ARRIVES ALOFT ALONG WITH MORE FAVORABLE
THERMODYNAMIC PARAMETERS AS DIURNAL HEATING COMMENCES. THE
CONVECTIVE THREAT SHOULD TEND TO INCREASE FARTHER SOUTH AS WELL
INTO AREAS OF NORTHERN AL.

EXPECT AS MUCH AS 4 TO 6 INCHES OF RAIN WITH ISOLATED HEAVIER
AMOUNTS...AND ESPECIALLY WITH A FAVORABLE ENVIRONMENT FOR SOME
BACKBUILDING AND TRAINING OF CONVECTIVE CELLS. FLASH FLOODING WILL
BE POSSIBLE.

ORRISON

ATTN...WFO...BMX...HUN...MEG...MRX...OHX...

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

LAT...LON   35898801 35548678 35108585 34608557 34098594
            34028657 34298754 35008834 35648858