Mesoscale Precipitation Discussion 0579
NWS Weather Prediction Center College Park MD
905 PM EDT Wed Aug 01 2018

Areas affected...South Central VA...Central NC...Central SC...

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

Valid 020105Z - 020530Z

SUMMARY...Favorable training/redevelopment environment with deep
rich moisture pose possible flash flooding threat through early
overnight...

DISCUSSION...Return southerly flow along western edge of
subtropical ridge combined with the large scale eastern trof
atmospheric river of moisture from the southern Gulf and western
Caribbean leading to a ribbon of Total PWATs in excess of 2" from
central GA to central VA toward the southern Chesapeake Bay. 
While, lapse rates are modest in the deeper moisture plume, the
interface with some mid-level drying and increased lapse rates
over Coastal Carolinas places the gradient of instability
accessible to developing convection within the main q-axis.
Cells/updrafts would be supported by 1500-2000 J/kg of MLCAPE that
will be waning with time.  Modest right jet entrance ascent also
supports deeper development with some organization to maintain
updrafts beyond initial development.  Regional RADARs mosaic does
denote the tilted (toward the west) nature of some of the updrafts
and loosely organized nature along prior outflow boundaries that
organized this round. Given deep moisture, rates up to 2"/hr are
likely with these cells.

VWP network depicts low level inflow is a bit stronger than
progged (still in the 25-30kt range in the 85-7H layer) and is
favorably aligned with the mean cloud bearing flow to support some
weak back-building/upstream redevelopment to support
training/repeat convective tracks over the next few hours, this is
particularly true further south into SC/S NC where new development
would not be robbed by upstream cells (as the case in Central
VA... which should see weakening trends earlier than south).  All
in all, with the rates and training environment 2-3" totals are
possible in spots and would be near 1 and 3hr FFG values in the
area making flash flooding possible tonight. 

Gallina

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

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

LAT...LON   38457778 37717733 34937993 34118071 34028118
            34228170 34778161 36568050 37887886