MESOSCALE PRECIPITATION DISCUSSION 0709
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
434 PM EDT WED SEP 28 2016
 
AREAS AFFECTED...CNTRL SC THROUGH MUCH OF CNTRL NC INTO FAR SRN VA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 282032Z - 290100Z
 
SUMMARY...A SHORT TERM THREAT OF FLASH FLOODING WILL EXIST ACROSS
THE CNTRL CAROLINAS INTO FAR SRN VA INTO THIS EVENING. RAINFALL
RATES PEAKING NEAR 2 IN/HR WITH TRAINING CAN BE EXPECTED TO
CONTINUE THROUGH 00Z.

DISCUSSION...RADAR IMAGERY AT 2015Z SHOWED A FEW AXES OF TRAINING
CONVECTION...FROM SW TO NE...LOCATED ACROSS NC AND NRN SC. DUAL
POL RADAR ESTIMATES FROM KRAX HAVE BEEN MAXIMIZING NEAR 2
IN/HR...WITH BLENDED TOTAL PRECIPITABLE WATER IMAGERY SHOWING
HIGHER VALUES OVER ERN NC VERSUS TO THE WEST. SPC MESOANALYSES
SHOWED THE AREA HAS SUFFICIENT INSTABILITY WITH A MAXIMUM IN
MLCAPE CENTERED OVER CNTRL NC BETWEEN 1500 AND 2000 J/KG. THESE
AREAS OF TRAINING ARE OCCURRING AHEAD OF A SHORTWAVE NOTED NEAR
THE SC/NC BORDER AT 20Z...AND AHEAD OF A POTENT MID-LEVEL JET
STREAK DEPICTED ON WATER VAPOR IMAGERY OVER TENNESSEE. SLOW
EVOLUTION OF THE SYNOPTIC SCALE FLOW OVER THE NEXT FEW HOURS WILL
KEEP KINEMATIC PROFILES IN PLACE TO SUPPORT REPEATING AXES OF
HEAVY RAIN.

WITH LFC-EL MEAN WINDS IN ALIGNMENT WITH THE LOW LEVEL
FLOW...REPRESENTED BY 20-30 KTS IN THE 850-700 MB LAYER...TRAINING
IS LIKELY TO CONTINUE IN THE SHORT TERM. WATER VAPOR IMAGERY
SHOWED EXPANSIVE DRYING ALOFT WITH RAP SOUNDINGS APPROXIMATING
THIS LAYER TO BE BETWEEN ABOUT 650 MB TO 400 MB...WHICH COULD
CAUSE DRY AIR ENTRAINMENT AND OUTFLOW DOMINANCE BEFORE 00Z.
HOWEVER...GIVEN RADAR TRENDS AND POOR HANDLING OF ONGOING TRAINING
AXES WITH RECENT AVAILABLE HI-RES MODELS...IT APPEARS A THREAT OF
FLASH FLOODING WILL EXIST FOR AT LEAST THE NEXT FEW HOURS ACROSS
MUCH OF CNTRL NC INTO NRN SC. SPECIAL CONCERN IS GIVEN TO AREAS IN
CNTRL NC WHICH HAVE EXPERIENCED RECENT HEAVY RAINFALL AND MAY BE
MORE SUSCEPTIBLE TO FLASH FLOODING. 

OTTO

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

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

LAT...LON   37127827 36957766 36817736 36077724 35337785 
            34707904 33868044 34108112 34518144 34978155 
            35328180 35678197 35998193 36528093 36967975 
            37097930