MESOSCALE PRECIPITATION DISCUSSION 0289
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
913 AM EDT MON AUG 18 2014
 
AREAS AFFECTED...SOUTHEASTERN TN/SOUTHWESTERN NC/NORTHEASTERN
AL/NORTHERN GA... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 181312Z - 181657Z
 
SUMMARY...UNIDIRECTIONAL FLOW ACROSS THE LOWER TN VALLEY HAS
PROMOTED TRAINING/BACKBUILDING CONVECTION THIS MORNING. EXPECT THE
ACTIVITY TO GRADUALLY SLIDE SOUTH AND EAST INTO THE BETTER
INSTABILITY DURING THE NEXT FEW HOURS.

DISCUSSION...THE 12Z BNA SOUNDING DEPICTED A VERY FAVORABLE
SOUNDING FOR HEAVY RAINFALL AND SLOW-MOVING CONVECTION. A NEARLY
SATURATED PROFILE WAS OBSERVED FROM THE SURFACE UP TO 675 MB WITH
STRONG LOW-LEVEL WESTERLY INFLOW AT 20 TO 30 KNOTS. THIS WIND
PROFILE WAS NEARLY EQUAL IN SPEED AND MAGNITUDE WITH THE
MEAN-CLOUD BEARING FLOW RESULTING IN NEARLY NEGLIGIBLE CORFIDI
VECTORS. DURING THE NEXT FEW HOURS THE PERSISTENT WESTERLY FLOW
WILL ADVECT THE HIGHER MOISTURE FROM THE ARKLATEX EASTWARD INTO
THE LOWER TN VALLEY AND DEEP SOUTH. THE ONGOING HEAVY RAINFALL HAS
BEEN PRODUCING 1 TO 2 INCH HOURLY RATES WITH ISOLATED POCKETS OF 3
INCHES PER DOPPLER DERIVED QPE. SUCH RATES SHOULD CONTINUE GIVEN
THE INTEGRITY OF THE CONVECTION HAS NOT CHANGED MUCH IN RECENT
SCANS.

MULTIPLE SHORTWAVES TRACKING EASTWARD SHOULD CONTINUE TO PROVIDE A
MID-LEVEL FOCUS FOR ADDITIONAL CONVECTION AS SURFACE HEATING
COMMENCES. THE GUIDANCE VARY WITH THE TIMING/PLACEMENT OF THIS
CONVECTION BUT THERE IS AGREEMENT THAT THE ONGOING ACTIVITY SHOULD
PERSIST AT LEAST ANOTHER FEW HOURS ACROSS NORTHERN GA.


RUBIN-OSTER

ATTN...WFO...GSP...MRX...FFC...OHX...BMX...HUN...

ATTN...RFC...LMRFC...OHRFC...SERFC...

LAT...LON   35028660 35378547 35448423 35148358 34558327 34098337
            33848404 33688537 33728630 34318698 35028660