MESOSCALE PRECIPITATION DISCUSSION 0689...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1209 PM EDT MON AUG 14 2017

CORRECTED FOR FIRST PARAGRAPH

AREAS AFFECTED...NORTHEAST SC & EASTERN NC

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

VALID 141604Z - 142204Z

SUMMARY...SHORT TRAINING BANDS OF CONVECTION ARE POSSIBLE TODAY. 
HOURLY RAIN TOTALS UP TO 2.5" WITH LOCAL AMOUNTS TO 4" ARE
ANTICIPATED.

DISCUSSION...SHOWERS AND THUNDERSTORMS ARE BEGINNING TO DEVELOP
ALONG LOCAL SEA BREEZE BOUNDARIES AT THE PRESENT TIME NEAR AND TO
THE NORTHEAST OF A NORTHWEST-SOUTHEAST ORIENTED 850 HPA TROUGH IN
SC AND TO THE SOUTHEAST/WITHIN THE WARM SECTOR OF A THERMAL
BOUNDARY NOTED IN THE SURFACE OBSERVATIONS NEAR AND EAST OF THE
FALL LINE.  WATER VAPOR IMAGERY SHOWS THAT THE FLOW ALOFT APPEARS
QUITE DIFFLUENT, BEING STRETCHED BY A SHORTWAVE MOVING THROUGH OH
AND AN UPPER LOW MOVING THROUGH THE SOUTHEAST GULF OF MEXICO. 
VISIBLE SATELLITE IMAGERY SHOWS CUMULIFORM CLOUDS DEVELOPING
ACROSS THE REGION.  INFLOW AT 850 HPA IS WEAK, IN THE 5-10 KT
RANGE OUT OF THE SOUTHWEST.  HOWEVER, EFFECTIVE BULK SHEAR IS
20-30 KTS PER RECENT SPC MESOANALYSES.  PRECIPITABLE WATER VALUES
ARE 2-2.25" IN THE AREA, A BIT ABOVE AVERAGE.  ML CAPE VALUES ARE
RISING, CURRENTLY IN THE 1000-2000 J/KG RANGE.

ADDITIONAL HEATING COULD LEAD TO ANOTHER 1000 J/KG OF ML CAPE TO
DEVELOP INTO THIS AFTERNOON, WHICH WOULD FOSTER ADDITIONAL
CONVECTIVE GROWTH. ANY STORMS THAT FORM NEAR THE THERMAL BOUNDARY
COULD SHIFT SOMEWHAT EASTWARD INTO AREAS OF HIGHER INSTABILITY
WITH TIME AS SEA BREEZE ACTIVITY MOVES IN FROM THE SOUTHEAST WHICH
COULD LEAD TO CELL MERGERS.  THE BULK SHEAR AVAILABLE COMBINED
WITH NEARLY UNIDIRECTIONAL FLOW WITH HEIGHT COULD LEAD TO SHORT
TRAINING BANDS, WHICH WOULD ALSO ENHANCE RAIN TOTALS.  HOURLY
TOTALS UP TO 2.5" WITH LOCAL AMOUNTS TO 4" ARE ANTICIPATED. 
RAINFALL DURING THE PAST WEEK HAS BEEN ~300% OF NORMAL, SO SOILS
ARE FAIRLY SATURATED.  WHILE ISSUES ARE NOT EXPECTED TO BE
WIDESPREAD, FLASH FLOODING IS POSSIBLE WHERE SHORT TRAINING BANDS
AND/OR CELL MERGERS OCCUR.

ROTH

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

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

LAT...LON   36417580 36417580 36207570 35907546 35577537
            35197550 35017592 34587644 34537668 34537713
            34127764 33817786 33697861 33337908 33137928
            33517959 34667928 35787762 36287648