MESOSCALE PRECIPITATION DISCUSSION 0468
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
500 PM EDT SAT JUL 16 2016
 
AREAS AFFECTED...NC....NORTHERN SC 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 162100Z - 170100Z
 
SUMMARY...SLOW-MOVING CLUSTERS OF THUNDERSTORMS WILL TEND TO
EXPAND A BIT MORE IN COVERAGE THROUGH THE LATE-AFTERNOON AND EARLY
EVENING HOURS. SOME FLASH FLOODING IS POSSIBLE GIVEN THE INTENSE
RAINFALL RATES AND POTENTIAL FOR TRAINING CELLS.

DISCUSSION...STRONG DIABATIC HEATING AND DEEP MOISTURE LOCKED IN
PLACE OVER THE SOUTHERN MID-ATLANTIC REGION HAS YIELDED MORE THAN
ENOUGH INSTABILITY FOR CLUSTERS OF THUNDERSTORMS TO DEVELOP AND
EXPAND IN COVERAGE OVER THE LAST COUPLE OF HOURS. BROADLY
CONFLUENT LOW LEVEL FLOW IS GENERALLY HELPING TO PROVIDE SOME LOW
LEVEL FOCUS FOR THE CONVECTION...BUT THE SOUTHERN MID-ATLANTIC
REGION...ESPECIALLY ACROSS WESTERN NC AND ADJACENT NORTHWEST
SC..IS BEGINNING TO ALSO COME UNDER THE INFLUENCE OF AN UPPER
TROUGH MOVING INTO THE OH VALLEY OF WHICH THE SOUTHERN PORTION OF
THIS EXTENDS DOWN INTO THE TN VALLEY. IMMEDIATELY DOWNSTREAM OF
THIS IS A CORRIDOR OF FAVORABLE RIGHT-ENTRANCE REGION JET DYNAMICS
AND THIS IS HELPING TO ACT AS A CATALYST FOR AT LEAST SOME OF THE
MORE ORGANIZED CLUSTERS SEEN OVER WESTERN NC. 

PWATS ARE ARE ON THE ORDER OF 1.9 TO 2.1 INCHES BASED ON THE
LATEST RAP ANALYSIS...AND THIS IS FOSTERING VERY INTENSE RAINFALL
RATES OF BETWEEN 2.5 AND 3.0 INCHES/HR. IN FACT...HICKORY NC
RECENTLY REPORTED 2.35 INCHES IN LESS THAN 1 HOUR.

OVER THE NEXT FEW HOURS...EXPECT AN ENVIRONMENT CONDUCIVE FOR
INTENSE THUNDERSTORM CLUSTERS...WITH SOME TRAINING SEGMENTS LIKELY
AS THE BANDS OF CONVECTION BECOME ORIENTED MORE PARALLEL TO THE
MEAN FLOW. HIRES GUIDANCE INDICATES A GRADUALLY WEAKENING OF
CONVECTION AFTER 00Z...BUT RAINFALL AMOUNTS OF 3 TO 5 INCHES WILL
BE POSSIBLE WITH SOME ISOLATED HEAVIER AMOUNTS. GIVEN SOME AREAS
OF NC AND SC HAVE SEEN VERY HEAVY RAINS THE LAST COUPLE OF
DAYS...THESE ADDITIONAL RAINS WILL INCREASE THE THREAT OF RUNOFF
PROBLEMS AND/OR FLASH FLOODING THIS EVENING.

ORRISON

ATTN...WFO...AKQ...CAE...GSP...MHX...RAH...

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

LAT...LON   36527643 36427601 35947603 35557691 35197801 
            34778010 34598147 34718270 35208278 35528204 
            35798044 36067888 36387768