MESOSCALE PRECIPITATION DISCUSSION 0261
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1028 AM EDT SUN MAY 29 2016
 
AREAS AFFECTED...EASTERN NC/SOUTHEAST VA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 291427Z - 292027Z
 
SUMMARY...THE CIRCULATION AROUND BONNIE INTERACTING WITH A COASTAL
FRONT AND DEVELOPING INSTABILITY COULD LEAD TO HOURLY RAIN RATES
UP TO 2.5".  FLASH FLOODING IS POSSIBLE.

DISCUSSION...TROPICAL DEPRESSION BONNIE IS MOVING NORTHWARD
THROUGH EASTERN SC.  INFLOW AT 850 HPA OF 20-30 KTS IS
INTERSECTING A NORTHWEST MOVING COASTAL FRONT MOVING THROUGH THE
COASTAL PLAIN OF THE CAROLINAS.  MLCAPES ARE 500-1000 J/KG PER SPC
MESOANALYSES ALONG THE NC COAST.  PRECIPITABLE WATER VALUES OF
1.8-2.2" HAVE POOLED ACROSS THE REGION PER GPS VALUES AND THE
MOREHEAD CITY NC 12Z SOUNDING.

THE MESOSCALE/CAM GUIDANCE SHOWS LOCAL AMOUNTS IN THE 2-4" RANGE,
WHICH COULD FALL QUICKLY.  INSTABILITY SHOULD INCREASE ACROSS
SUNNY PORTIONS OF THE NC COASTAL PLAIN SOUTHEAST OF THE COASTAL
FRONT -- EXPECTED TO RISE INTO THE 1500-2000 J/KG RANGE. 
LOW-LEVEL INFLOW SHOULD REMAIN FAIRLY STATIC TODAY.  THE AVAILABLE
PARAMETERS SUPPORT HOURLY RAIN RATES UP  TO 2.5", WHICH APPEARS
MOST LIKELY ALONG SHORT TRAINING BANDS NEAR THE COASTAL FRONT AS
THE FLOW IS NEARLY UNIDIRECTIONAL OUT OF THE SOUTH.  THE GFS-BASED
GALVEZ-DAVISON INDEX INDICATES THAT CONVECTIVE COVERAGE SHOULD
INCREASE BETWEEN NOW AND 21Z, WITH VALUES CLIMBING ABOVE 40 WITH
TIME, INDICATING NUMEROUS THUNDERSTORMS.  THE DEGREE THE COASTAL
FRONT MOVES INLAND IS DIRECTLY RELATED TO BONNIE'S TRACK, AND SO
FAR THE STORM'S FORWARD MOTION HAS EXCEEDED EXPECTATIONS.  USED
RECENT RAP RUNS TO ATTEMPT TO GET A HANDLE ON THE BOUNDARY'S
FUTURE LOCATION. 

ROTH

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

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

LAT...LON   37227644 36197559 35297666 34117861 34667920 
            36107829