MESOSCALE PRECIPITATION DISCUSSION 0731
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
855 PM EDT SAT OCT 08 2016
 
AREAS AFFECTED...ERN NC INTO SERN VA AND THE SRN DELMARVA
PENINSULA 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING LIKELY 
 
VALID 090054Z - 090654Z
 
SUMMARY...DESPITE THE STEADY WEAKENING OF HURRICANE
MATTHEW...FLASH FLOODING FROM RAINFALL RATES OF 2-3 IN/HR WILL
REMAIN LIKELY ACROSS NERN NC INTO FAR SERN VA. ADDITIONAL 6 HR
RAINFALL TOTALS ARE EXPECTED TO RANGE FROM 4 TO 8 INCHES THROUGH
07Z...WITH LOCALLY HIGHER TOTALS RESULTING IN DANGEROUS FLOODING.

DISCUSSION...AT 00Z...ENEWD MOVING HURRICANE MATTHEW WAS LOCATED
ROUGHLY 40 MILES EAST OF CAPE FEAR NC...BUT THE HEAVIEST RAINFALL
HAS BEEN DISPLACED NNW OF THE CENTER OVER NERN NC INTO SERN VA. IT
IS HERE THAT STRONG FRONTOGENESIS WAS NOTED IN THE 850-700 MB
LAYER...WITH STEADY RAINFALL RATES OF 1-2 IN/HR OBSERVED OVER THE
PAST 3 TO 6 HOURS. FARTHER SOUTH...EARLIER RAINFALL OF OVER 9
INCHES IN 3 HOURS WAS REPORTED AND VERIFIED AT GSB ENDING AT
21Z...DESPITE MINIMAL INSTABILITY. THE 00Z SOUNDING FROM MHX
REPORTED A PRECIPITABLE WATER VALUE OF 2.72 INCHES WITH VALUES
FALLING OFF TO THE NORTH WITH 1.93 INCHES REPORTED AT WAL. 

TRENDS IN INFRARED SATELLITE IMAGERY CONTINUED TO SHOW AN
IMPRESSIVE BAROCLINIC LEAF SIGNATURE OVER THE NRN MID-ATLANTIC
REGION ALONG WITH THE RIGHT ENTRANCE REGION OF A POWERFUL UPPER
LEVEL JET FOCUSED OVER THE NC/VA BORDER. CNTRL AND ERN NC HAS BEEN
UNDER THE INFLUENCE OF STRONG UPPER LEVEL DIVERGENCE AND
DIFFLUENCE THROUGH SATURDAY AFTERNOON...BUT AS MATTHEW CONTINUES
TO WEAKEN OVERNIGHT AND AS A 150-170 KT JET CORE AT 200 MB
TRANSLATES NEWD FROM SRN ONTARIO...UPPER LEVEL LIFT WILL WEAKEN
WHICH SHOULD ALLOW RAINFALL INTENSITY TO DIMINISH COMPARED TO
EARLIER TODAY.  HOWEVER...GIVEN TROPICAL MOISTURE IN
PLACE...ONGOING HEAVY RAIN AND THE FACT THAT THE MAGNITUDE OF
FRONTOGENETIC FORCING WILL SUSTAIN ITSELF OVER THE NEXT 6 HOURS IN
THE PRESENCE OF STRONG 850-700 MB CONVERGENCE...FLASH FLOODING
REMAINS LIKELY.

OTTO

ATTN...WFO...AKQ...LWX...MHX...PHI...RAH...

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

LAT...LON   38617501 38267461 36697532 35357513 34697621 
            35047778 36247822 37357776 38287592