MESOSCALE PRECIPITATION DISCUSSION 0541...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
435 AM EDT FRI OCT 02 2015
 
CORRECTED FOR MATCHING THE COLOR OF THE TEXT TO THE FORECAST
ATTRIBUTE

AREAS AFFECTED...COASTAL SC/NC... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 020813Z - 021413Z
 
SUMMARY...AN UPTICK IN THE HOURLY RAINFALL RATES ALONG THE NC/SC
HAVE BEEN NOTED WITH VALUES APPROACHING THE 0.75 TO 1 INCH RANGE.
INSTABILITY HAS BEEN CONFINED TO THE COASTAL WATERS BUT SHOULD
SLOWLY MIGRATE INLAND CARRYING SOME OF THE DEEPER CONVECTION INTO
COASTAL LOCATIONS. DEEP-LAYERED MOISTURE COMBINED WITH STRONG
LOW-LEVEL CONVERGENCE SHOULD PROMOTE HEAVY RAINFALL CAPABLE OF
PRODUCING A THREAT FOR FLASH FLOODING THROUGH THE MORNING.

DISCUSSION...THE 08Z SURFACE ANALYSIS INDICATED A WELL-DEFINED
FRONT JUST OFFSHORE OF THE CAROLINA COAST WITH ABUNDANT MOISTURE
IN PLACE AS PWATS REMAIN IN THE 2 TO 2.25 INCH RANGE. THE DEEPEST
CONVECTION OVERNIGHT HAS BEEN IN THE COASTAL WATERS WITH CLOUD
TOPS REACHING -70C IN SOME OF THE STRONGER UPDRAFTS. SOME OF THE
HEAVIER RAINFALL HAS BEGUN TO SPREAD INLAND PER MESONET
OBSERVATIONS FROM ALONG THE NC/SC BORDER WHERE 1.60 INCHES HAS
FALLEN IN THE PAST 2 HOURS. EXPECT THE COVERAGE OF HEAVY RAINFALL
TO CONTINUE TO EXPAND AND MIGRATE INLAND DURING THE NEXT SEVERAL
HOURS. THIS NOTION IS SUPPORTED BY MANY OF THE MESOSCALE MODELS.
ONE OF THE MAJOR LIMITING FACTORS IS THE LACK OF INSTABILITY WITH
CURRENT MUCAPES BELOW 500 J/K OVER THE COASTLINE. MANY SOLUTIONS
DO SHOW THESE HIGHER BUOYANCY PROFILES SLOWLY ADVECTING INLAND
WHICH WOULD BRING SOME OF THE HIGHER RAINFALL RATES INTO NC/SC.

EVALUATING THE PAST SEVERAL RUNS OF THE HRRR...THERE HAS BEEN A
NOTABLE WESTWARD TREND IN THE 6-HOUR PRECIPITATION ENDING AT 12Z.
THUS...ADJUSTED THE MPD AREA A BIT MORE INLAND TO ACCOUNT FOR
THESE MULTI-CYCLE TRENDS. OTHER AVAILABLE CAMS TENDED TO FAVOR A
SOLUTION CLOSER TO THE COAST. DECIDED TO ACCOUNT FOR BOTH
SCENARIOS HERE AND WILL LET DAY SHIFT RE-EVALUATE THE SITUATION.
PLEASE VIEW THE LATEST SPE FROM NESDIS/SAB FOR MORE INFORMATION ON
THIS EVENT.

RUBIN-OSTER

ATTN...WFO...AKQ...CAE...CHS...ILM...MHX...RAH...

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

LAT...LON   36037693 35207589 34347658 33237829 31717970 
            32008075 33468049 34847953 35857839