Mesoscale Precipitation Discussion 0556
NWS Weather Prediction Center College Park MD
237 PM EDT Sun Jul 29 2018

Areas affected...portions of southeastern GA into central SC/NC

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

Valid 291835Z - 300035Z

SUMMARY...Slow moving scattered thunderstorms with rain rates of
2-3 in/hr will be possible through the remainder of the afternoon
into the evening hours. 6 hour totals of 3-6 inches can be
expected on a localized basis from eastern GA into portions of SC
and eastern NC to the VA border.

DISCUSSION...18Z surface observations placed a quasi-stationary
front from the northern NC coast extending southwestward into
central GA. Moisture along and east of this front was high with
surface dewpoints well into the 70s and precipitable water values
within a quarter inch of 2.0 inches. Similar to yesterday, flow in
the low to mid-levels is less than 20 kt which will limit storm
organization. However, the tail end of a 50-70+ kt upper level jet
located from the Mid-Atlantic region into New England (via 12Z
RAOB data) may allow for some enhanced upper level divergence over
the Carolinas through the afternoon.

Convection is already underway across the Carolinas, with slow
movement noted in a few cells. Convection along an inland
progressing sea breeze was observed over SC into southern NC, with
additional convection likely via surface convergence along the
stationary boundary located a bit farther inland. These storms and
forecast convergence from outflows between these two regions will
have the potential to produce 2-3 in/hr rainfall rates with cell
mergers and outflow interactions locally enhancing lift. While not
expected to be widespread, local hang ups and storm scale
enhancements will have the potential to produce 3-6 inch totals in
a few locations through 01Z. There is a good consensus in the
latest hi-res models to support this idea as well.

Otto

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

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

LAT...LON   36697632 36587589 36347568 36067581 35617647
            34787748 33457973 32558120 32328199 32378255
            32708286 33548269 34528107 35317933 36147828
            36447777 36627710