Mesoscale Precipitation Discussion 0851
NWS Weather Prediction Center College Park MD
429 PM EDT Sun Sep 16 2018

Areas affected...Central and Southern NC...North Central to
Eastern SC...

Concerning...Heavy rainfall...Flash flooding possible

Valid 162030Z - 170230Z

SUMMARY...Highly focused outer bands with enhanced rainfall
supported by training and backbuilding that will compound ongoing
life-threatening flash flooding.

DISCUSSION...GOES-16 imagery suite and RADAR mosaic show a
distinct separation of the surface low and the mid-level center. 
The surface low is currently in Laurens county starting to lift
more N of due NW, while the mid-level center is in north central
SC in Lancaster county.  This center has become more organized
with tighter curvature indicative of enhanced DPVA along the
eastern quadrant as well as, upper level diffluent outflow across
much of NC.  Low level flow has responded with strengthening of
convergent flow along outer band from Montgomery county NC to
Dillon, SC to new development at the tail in far eastern
Charleston, SC county.  Rapid IR cooling into the mid -60C temp 
Instability of 1500-2500 J/kg collocated with total PWATs in the
2.4" range suggest 3"/hr rain rates are likely.

Given training profile, the potential for 4" totals in one hour
are possible, though more broadly will support 2"/hr rates even as
best flux is reduced as the DPVA wave passes.  Along the tail end
of this wave across E SC, flow becomes more confluent and focuses
training upstream better...as such expansion across Marion/Horry
counties in the next few hours will support training an continued
likely flash flooding, with 6-8" totals possible through 03z.

Instability reduces below 100 J/kg into Central NC, and
thunderstorms lose vertical depth for rainfall generation, yet
overall confluent more gentle ascent within the moisture rich area
will support rates up to 1"/hr and totals of 2-4" over the next 6
hours expanding flooding areas further north into North central
NC. 

Further east, a shallower convection/more broken band exist from
Harnett to Pender county, best convergence has reduced inflow and
band should continue a downward trend. Yet individual cells are
capable of 1.5"/hr with some training supporting 1-1.5" totals in
the next hour or so.  Given extreme totals, this will continue
flash flooding conditions in the area.

Gallina

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

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

LAT...LON   36138001 36127930 35987889 35137788 34827757
            34537728 34257754 34227780 34467800 34567846
            33887843 33647876 33257906 33157899 33027948
            33307970 33917975 34568034 35028114 35468109
            35898056