MESOSCALE PRECIPITATION DISCUSSION 0170
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
353 PM EDT MON MAY 02 2016
 
AREAS AFFECTED...PORTIONS OF THE CAROLINAS 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 021952Z - 030052Z
 
SUMMARY...THUNDERSTORMS ARE GROWING IN INTENSITY AND COVERAGE
ACROSS PORTIONS OF SC AND SOUTHERN NC.  AS CELLS MERGE AND ATTEMPT
TO TRAIN, FLASH FLOODING BECOMES A CONCERN.

DISCUSSION...SATELLITE AND RADAR TRENDS SHOW AN EXPANSION OF
CONVECTION NEAR AND EAST OF THE DEW POINT GRADIENT WHICH IS FOUND
NEAR THE GRADIENT IN THE TOPOGRAPHY NEAR AND NORTHWEST OF THE FALL
LINE.  BULK SHEAR IN THE 0-6 KM LAYER FOSTERS ORGANIZED
THUNDERSTORM ACTIVITY, WHICH HAS BEEN MOVING EAST-NORTHEAST AT
20-25 KTS.  THESE STORMS ARE HELPING TO REINFORCE A WEAK
TEMPERATURE/DEW POINT GRADIENT WHICH SHOULD BECOME A MORE
EFFECTIVE FOCUS FOR CONVECTION, WHICH HAS BEGUN TO MANIFEST ITSELF
WITHIN THE MLCAPE FIELD PER THE 19Z SPC MESOANALYSIS. 
PRECIPITABLE WATER VALUES ARE NEAR 1.5" PER GPS VALUES AND
CONVERGENT 850 HPA INFLOW OF 15-20 KTS IS BEING FUNNELED INTO THE
REGION.  MLCAPES ARE IN THE 1000-2000 J/KG RANGE.

OVER THE NEXT SEVERAL HOURS, INFLOW AT 850 HPA IS EXPECTED TO
SLOWLY INCREASE, WHICH COULD FURTHER ENHANCE THE CONVECTIVE
POTENTIAL.    THE 12Z GFS-BASED GALVEZ-DAVISON INDEX PEGS THIS
REGION TO HAVE THE GREATEST OVERALL CONVECTIVE INSTABILITY,
HINTING AT FURTHER GROWTH OF THE CONVECTIVE FIELD INTO MORE
NUMEROUS THUNDERSTORM ACTIVITY.  AS DISORGANIZED PULSE CONVECTION
ATTEMPTS TO MOVE NORTHEAST AT 25-30 KTS, ORGANIZED CONVECTION
SHOULD PICK UP THE PACE MORE TOWARDS THE EAST AT 25-30 KTS, WHICH
COULD LEAD TO MORE CELL MERGERS.  IF THE BOUNDARY CONTINUES TO GET
BETTER DEFINED, WHICH SEA BREEZE CONVERGENCE MIGHT AID ON THE
EASTERN SIDE OF THIS AREA IN NC, SOME SHORT PERIODS OF CELL
TRAINING COULD RESULT.  THE MESOSCALE/CAM GUIDANCE SHOWS A SIGNAL,
BEST SEEN IN THE 12Z ARW/SOUTHWARD ADJUSTED 12Z SPCWRF/18Z HRRR,
FOR LOCAL AMOUNTS IN THE 3-5" BEING POSSIBLE.  WITH HOURLY RAIN
RATES UP TO 2" EXPECTED TO CONTINUE, FLASH FLOODING IS CONSIDERED
POSSIBLE, PARTICULARLY WITHIN THE COLUMBIA SC AND CHARLOTTE NC
METROPOLITAN AREAS.  UNCERTAINTY IS MODERATE IN THIS REGION DUE TO
THE DIFFERING MESOSCALE/CAM GUIDANCE IN THIS AREA.

ROTH

ATTN...WFO...CAE...GSP...ILM...MHX...RAH...

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

LAT...LON   36017849 35757736 34817762 34217889 33698063 
            33708200 34158272 34608249 35178157 35718040