MESOSCALE PRECIPITATION DISCUSSION 0144
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
745 PM EDT MON APR 24 2017

AREAS AFFECTED...CENTRAL AND SOUTHEAST NC

CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY

VALID 242345Z - 250545Z

SUMMARY...ADDITIONAL HEAVY RAIN AND CONCERNS FOR FLASH FLOODING
WILL PERSIST THROUGH THE EVENING HOURS.

DISCUSSION...DEEP LAYER SOUTHEAST FLOW AROUND THE NORTHEAST FLANK
OF A STRONG CLOSED LOW CENTER PIVOTING EAST ACROSS EASTERN GA
CONTINUES TO TRANSPORT A SIGNIFICANT AMOUNT OF ATLANTIC MOISTURE
INLAND ACROSS MUCH OF CENTRAL AND SOUTHEAST NC. THIS IS COINCIDING
WITH A FOCUSED AXIS OF ASCENT TOO GIVEN NOTABLY DIFFLUENT FLOW
ALOFT...ISENTROPIC LIFT OVER A WELL-DEFINED FRONTAL ZONE NEAR THE
COAST AND PERSISTENTLY CONFLUENT LOW LEVEL FLOW.

PWATS ACROSS THE REGION ARE RUNNING 2 TO 3 STANDARD DEVIATIONS
ABOVE NORMAL...WITH VALUES GENERALLY BETWEEN 1.5 AND 1.75 INCHES.
THIS ANOMALOUS MOISTURE PROFILE THOUGH IS IN PART BEING
FACILITATED BY THE INTERACTION OF THE DEEP CLOSED LOW OVER EASTERN
GA WITH THE AREA OF LOW PRESSURE AND ASSOCIATED MID LEVEL ENERGY
OVER THE WESTERN ATLANTIC. A MUCH DEEPER POOL OF TROPICAL MOISTURE
IS NOTED WITH THIS OFFSHORE SYSTEM...BUT THE CIRA-LPW PRODUCT
CONFIRMS A CLEAR TAP OF OF 850/700MB AND 700/500MB MOISTURE FROM
OFFSHORE THAT IS BEING TRANSPORTED INLAND OVER NC. THEREFORE WE
ARE LIKELY SEEING SOME ENHANCED RAINFALL EFFICIENCY THROUGH SOME
SEEDER-FEEDER PROCESSES AND HEAVIER RESULTING RAIN RATES.

THE LATEST HRRR AND HRRRX GUIDANCE CONTINUES TO ADVERTISE
ADDITIONAL HEAVY RAINS THROUGH THE EVENING WITH ANOTHER 2 TO 4
INCHES AND POSSIBLY HEAVIER AMOUNTS TO NEAR 5 INCHES GOING THROUGH
06Z. THE HEAVIEST AMOUNTS SHOULD TEND TO BE CLOSER TO THE
IMMEDIATE COAST WHERE THERE IS CLOSER PROXIMITY TO AN INSTABILITY
GRADIENT AND SOMEWHAT STRONGER SURFACE CONVERGENCE.

GIVEN THE ADDITIONAL RAINFALL AND SATURATED SOIL
CONDITIONS...RUNOFF PROBLEMS AND SOME FLASH FLOODING WILL REMAIN
LIKELY.

ORRISON

ATTN...WFO...ILM...MHX...RAH...

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

LAT...LON   36037857 36027816 35347718 34907670 34617677
            34447731 34267755 33997769 33767795 33857838
            34467883 34847926 35367943 35867921