MESOSCALE PRECIPITATION DISCUSSION 0345
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
929 PM EDT MON JUN 19 2017

AREAS AFFECTED...CENTRAL NC...SERN VA

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

VALID 200129Z - 200500Z

SUMMARY...TRAINING OF CONVECTIVE CELLS IN AN AREA FROM NORTH CNTRL
NC TO SERN VA OVER THE NEXT FEW HOURS COULD PRODUCE LOCALIZED
RAINFALL AMOUNTS OF 2-4". FLASH FLOODING IS POSSIBLE.

DISCUSSION...A BAND OF CONVECTION HAS DEVELOPED THIS EVENING ALONG
AN INSTABILITY GRADIENT FROM N-CNTRL NC TO SERN VA. THE ATMOSPHERE
REMAINS MOIST AND UNSTABLE TO THE SOUTH OF THE CONVECTION WITH
MLCAPES OF 1000-2000 J/KG AND AND SURFACE DEW POINTS IN THE MID
70S. SOUTHERLY FLOW OF 10-15 KT WAS OBSERVED FROM THE AREA OF
CONVECTION SOUTHWARD TO THE COASTLINE, WITH 925 HPA SOUTHERLY FLOW
OF 30-40 KT IN THIS SAME AREA NOTED ON THE LATEST SPC
MESOANALYSIS, PROVIDING DECENT MOIST AND UNSTABLE LOW-LEVEL INFLOW
TO THE CONVECTION. ALOFT, MODERATELY DIFFLUENT FLOW WAS NOTED AT
300 HPA IN THE RIGHT ENTRANCE REGION OF A JET STREAK CENTERED OVER
THE APPALACHIANS, PROVIDING UPPER-LEVEL SUPPORT AS WELL.
LOW/MID-LEVEL BASED ON LATEST RAP DATA, WIND PROFILES SEEM TO
SUPPORT SOME DEGREE OF BACKWARD PROPAGATION, WHICH COULD RESULT IN
CONTINUED AREAS OF LOCALIZED CELL TRAINING.

THE LATEST OPERATIONAL HRRR RUN SEEMS TO HAVE A GOOD HANDLE ON
THIS CONVECTION AND SHOWS AN ADDITIONAL 2 TO 4 INCHES POSSIBLE
OVER THE NEXT SEVERAL HOURS FROM EXTREME N-CNTRL NC AND
NORTHEASTWARD INTO SERN VA. GIVEN THE HIGHLY MOIST AND MODERATELY
UNSTABLE AIR MASS, RATES OF 2-3 IN/HR ARE POSSIBLE IN THE HEAVIEST
CELLS. FLASH FLOODING IS POSSIBLE.

RYAN

ATTN...WFO...AKQ...GSP...RAH...RNK...

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

LAT...LON   37607708 37387654 36847682 36097765 35657882
            35477975 35718043 35988045 36357994 36877899
            37427799