MESOSCALE PRECIPITATION DISCUSSION 0424
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
918 PM EDT TUE OCT 14 2014
 
AREAS AFFECTED......WESTERN NC/WESTERN VA/SOUTHERN WV... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 150118Z - 150503Z
 
SUMMARY....LOW TOPPED CONVECTION WILL PRODUCE HEAVY RAIN OVER
AREAS THAT RECEIVED AS MUCH AS 4 INCHES OF RAIN IN THE PAST 12
HOURS. THE ADDITIONAL RAINFALL COULD RESULT IN FLASH FLOODING.

DISCUSSION...THE COMBINATION OF MINIMAL INSTABILITY AND
PRECIPITABLE WATER VALUES BETWEEN 1.60 AND 1.90 INCHES WILL FEED
LOW TOPPED CONVECTION MOVING NORTHWARD ACROSS NORTHWEST
SC...WESTERN NC AND WESTERN VA. MESONET OBSERVATIONS AND RADAR
ESTIMATES INDICATE THAT RAINFALL RATES OVER AN INCH AN HOUR HAVE
ACCOMPANIED THE CONVECTION AS IT MOVES THROUGH NORTHWEST SC. 

THE CONVECTION IS FOLLOWING THE REMAINING INSTABILITY AND MOISTURE
ACROSS AREAS THAT RECEIVED BETWEEN 2 AND 4 INCHES OF RAIN DURING
THE PAST 12 HOURS. THE LATEST HRRR AND RAP SUGGESTS THAT ENOUGH
INSTABILITY REMAINS TO SUSTAIN THE CURRENT CONVECTION THROUGH
ABOUT 05Z. BOTH MODELS SHOW QPF AMOUNTS NEAR 2 INCHES DURING THAT
TIME... ESPECIALLY ACROSS WESTERN NC AND WESTERN VA.

THE EARLIER RAINFALL HAS LOWERED ONE HOUR FLASH FLOOD GUIDANCE TO
AS LOW AS AN INCH ACROSS PORTIONS OF WESTERN NC AND WESTERN VA.
THE ADDITIONAL RAINFALL COULD RESULT IN ADDITIONAL FLASH
FLOODING...AND EXACERBATION OF EARLIER FLOODING. 

INSTABILITY SHOULD BECOME THE LIMITING FACTOR FOR SUSTAINING THE
CONVECTION...AND AS MENTIONED EARLIER...THE LATEST HIGH RESOLUTION
GUIDANCE SUGGESTS THAT THE CONVECTION SHOULD WEAKEN AFTER 05Z.

HAYES

ATTN...WFO...GSP...MRX...RAH...RLX...RNK...

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

LAT...LON   38118133 37898034 36588008 35358101 34458176 
            34328272 34578327 35458351 35978320 36938247