MESOSCALE PRECIPITATION DISCUSSION 0537
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1002 PM EDT WED SEP 30 2015
 
AREAS AFFECTED...NORTHEASTERN SC/CENTRAL TO EASTERN NC/FAR
SOUTHEASTERN VA... 
 
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE 
 
VALID 010201Z - 010631Z
 
SUMMARY...SLOW-MOVING CONVECTION CONSISTING OF MULTIPLE CELL
MERGERS HAS LED TO SOME LOCAL HEAVY RAINFALL WITH HOURLY RATES
EXCEEDING 1.50 INCHES PER RECENT OBSERVATIONS. GIVEN FAIRLY
UNIDIRECTIONAL FLOW AND TALL/SKINNY CAPE PROFILES...FLASH FLOODING
WILL BE POSSIBLE ACROSS THE REGION.

DISCUSSION...THE 01Z SURFACE ANALYSIS DEPICTED A SOUTHWEST TO
NORTHEAST ORIENTED BOUNDARY WHICH WAS NEARLY QUASI-STATIONARY IN
NATURE. A GRADUAL MOTION INLAND IS EXPECTED AS THE BOUNDARY
RETURNS AS A SLOW-MOVING WARM FRONT OVERNIGHT. ABUNDANT MOISTURE
CONTINUES TO OVERRUN THIS BOUNDARY WITH 2 TO 2.25 INCH PWATS
DEPICTED VIA GPS DATA AND LOCAL 00Z RAOBS. IN PARTICULAR...THE 00Z
MHX SOUNDING SHOWED IMPRESSIVE MOISTURE IN PLACE WITH 2.13 INCH
PWATS COUPLED WITH NEARLY UNIDIRECTIONAL SOUTH-SOUTHWESTERLY FLOW
ANCHORING MUCH OF THE TROPOSPHERE. THE INSTABILITY PROFILE WAS
TALL/SKINNY IN NATURE WHICH SUPPORTS THE POTENTIAL FOR FLASH
FLOODING. RECENT RADAR IMAGERY OVER THE MPD AREA SHOWED ACTIVE
CONVECTION WITH MULTIPLE CELL MERGERS NOTED. THESE HAVE ALREADY
SPAWNED NUMEROUS FLASH FLOOD WARNINGS WITH SUCH ISSUES LIKELY
PERSISTING INTO THE OVERNIGHT HOURS. THE ONE QUESTION IS HOW MUCH
INSTABILITY WILL LINGER ACROSS THE REGION. THE 01Z RAP SUGGESTED
THE GREATEST BUOYANCY WILL BE CLOSER TO THE COAST. SO EXPECT THE
RAINFALL RATES TO COME DOWN AS THE CONVECTION SPREADS FARTHER
INLAND AWAY FROM THE BETTER INSTABILITY. PLEASE VIEW THE LATEST
SPE FOR MORE INFORMATION FROM THE SATELLITE PERSPECTIVE. WILL
RE-ASSESS THE SITUATION UPON EXPIRATION.

RUBIN-OSTER

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

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

LAT...LON   36667699 36327671 35797673 35127735 34457877 
            34117937 33737985 33858025 34338050 34818063 
            35478030 35887901 36627779