MESOSCALE PRECIPITATION DISCUSSION 0710...CORRECTED
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
907 PM EDT WED SEP 28 2016
 
CORRECTED FOR TYPO IN SECOND TO LAST PARAGRAPH

AREAS AFFECTED...E-CNTRL VA INTO THE SRN DELMARVA PENINSULA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 290103Z - 290703Z
 
SUMMARY...WIDESPREAD 3-6 INCH RAINFALL WITH LOCALLY HIGHER TOTALS
ARE EXPECTED THROUGH 07Z FROM PORTIONS OF S-CNTRL NC INTO CNTRL
AND ERN VA...EXTENDING INTO THE SRN DELMARVA PENINSULA. GIVEN THIS
WILL FALL ON TOP OF PREVIOUS RAINFALL FROM EARLIER TODAY...FLASH
FLOODING IS LIKELY.

DISCUSSION...REGIONAL RADAR OVER THE PAST COUPLE OF HOURS HAS
SHOWN CONTINUED PERIODS OF TRAINING RAINFALL FROM THE CNTRL SC/NC
BORDER INTO SERN VA WITH A RECENT EXPANSION OF COVERAGE JUST EAST
OF I-85 IN CNTRL NC. RAINFALL RATES HAVE BEEN AS HIGH AS 3 IN/HR
AS SEEN NEAR THE RICHMOND METRO ENDING 23Z...FOCUSING NEAR A
REMNANT COASTAL FRONT ANALYZED FROM SERN VA INTO SWRN DE AT 00Z.
INSTABILITY NW OF THIS REMNANT BOUNDARY HAS BEEN LIMITED WITH
HIGHER MUCAPE VALUES EXTENDING ACROSS ERN NC INTO SERN VA AND OVER
THE SRN DELMARVA PENINSULA.

AS A LARGE CLOSED UPPER LEVEL LOW CONTINUES TO SINK SOUTH ACROSS
THE CNTRL OH VALLEY OVER THE NEXT 3-6 HOURS...UPPER LEVEL
DIFFLUENCE WILL INCREASE ACROSS THE ERN HALF OF NC AND VA AS FLOW
BACKS TO THE EAST OF THE UPPER LOW. A CORRIDOR OF ENHANCED 850 MB
FLOW OF ABOUT 25 KTS FROM THE SW EXTENDED FROM THE CNTRL SC/NC
BORDER INTO SERN VA VIA AREA VAD WIND PLOTS. THESE WINDS ARE
FORECAST TO REMAIN IN PLACE WITH SLIGHT STRENGTHENING THROUGH
06Z...WHICH SHOULD PROLONG TRAINING AXES OF HEAVY RAIN...WITH
RAINFALL RATES OF GENERALLY 1-2 IN/HR...WITH LOCALLY HIGHER RATES
POSSIBLE. 

EXPERIMENTAL HRRR FORECASTS HAVE UNDERDONE RAINFALL ACROSS S-CNTRL
NC...BUT HAVE DONE RATHER WELL ACROSS VA. USING A COMBINATION OF
THE PAST FEW RUNS OF THE EXPERIMENTAL HRRR AND RADAR TRENDS
SUPPORTS AN AXIS OF VERY HEAVY RAIN FROM S-CNTRL NC INTO THE SRN
DELMARVA PENINSULA THROUGH 07Z WITH LIKELY FLASH FLOODING. 

OTTO

ATTN...WFO...AKQ...GSP...LWX...PHI...RAH...RNK...

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

LAT...LON   38967634 38927561 38587534 37977541 37437602 
            36637712 35287892 35197999 35548041 36268002 
            36977946 37747875 38937722