MESOSCALE PRECIPITATION DISCUSSION 0919
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
158 AM EDT SUN OCT 29 2017

AREAS AFFECTED...SOUTHEAST NORTH CAROLINA

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

VALID 290600Z - 291100Z

SUMMARY...TRAINING THUNDERSTORMS WITH CONTINUAL UPSTREAM
REDEVELOPMENT LIKELY POSE 2-4" TOTALS AND ISOLATED FLASH FLOODING
RISK

DISCUSSION...A SUBTLE SHORTWAVE LOCATED OVER THE CENTRAL CAROLINAS
IS LIFTING NNE BUT ALONG WITH SLIGHT DIFFLUENCE IN 3H JET
COINCIDENT WITH SURFACE CONFLUENCE ACROSS SE NC HAS GENERATED AN
ENVIRONMENT TO ENHANCE SHALLOW CONVECTION ALONG THE GULF STREAM
THIS MORNING.  CURRENTLY SFC SELY FLOW OF 20-25KT  IS CONVERGING
WITH SOUTHWESTERLY FLOW OFF SC WITH AMPLE MOISTURE FLUX ON THE
SELY FLOW...TPWS HAVE RISEN TO 1.5" TOWARD THE WILMINGTON, NC
METRO.  MODEST INSTABILITY DUE TO THE WARM GULF STREAM EXISTS HERE
AS WELL WITH MLCAPE TO 750 J/KG AND SBCAPES TO 1250 J/KG TO
PROVIDE LOW LEVEL UVV VIGOR BEFORE REACHING BETTER UPPER LEVEL
SUPPORT.  THIS ELEMENTS ARE SUPPORTIVE OF WARM CLOUD PROCESS RAIN
PRODUCTION WITH RATES OF 1.5"/HR WITH OCCASIONAL STRONGER CORES
CAPABLE OF 2"/HR RATES.

RAP FORECASTS SUGGEST FORCING BOTH IN THE LOW LEVELS AND MID-LEVEL
SHOULD BE FAIRLY CONSISTENT EVEN AS THE WAVE LIFTS AWAY AND LOW
LEVEL INFLOW (850MB) FLOW SLACKS. PERSISTENT FAIRLY UNIDIRECTIONAL
CLOUD BEARING FLOW WILL SUPPORT A TRAINING CORRIDOR WITH SLIGHT
EASTWARD DRIFT WITH A FAIRLY ANCHORED REDEVELOPMENT
SOURCE...LEADING TO GREATEST POTENTIAL FOR TRAINING ACROSS E
BRUNSWICK/NEW HANOVER AND PENDER COUNTIES.  AS SUCH 1-3" TOTALS
FURTHER NORTH MAY POSE FLOODING ISSUES ACROSS S MHX CWA WHERE
DURATION OF TRAINING IS LESS AND 2-4" TOTALS WITH POSSIBLE 5"
TOTAL LOCALLY.  LIMITING FACTOR LIKELY TO BE RECENT DRY CONDITIONS
AND HIGHER FFG VALUES STILL THIS MAY STILL POSE A FLOODING CONCERN
THROUGH 10Z THIS MORNING.  THIS SCENARIO IS BEST SUPPORTED BY
RECENT HRRR AND ESRL HRRRV3 TRENDS AS WELL AS THE 00Z ARW/NSSL-WRF
RUNS PROVIDING SOME MODEST CONFIDENCE.

GALLINA

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

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

LAT...LON   35437702 35237643 34587647 34407737 33797783
            33787842 33997854 34927804 35247776 35427741