796
AWUS01 KWNH 111626
FFGMPD
NCZ000-SCZ000-GAZ000-112225-

Mesoscale Precipitation Discussion 0861
NWS Weather Prediction Center College Park MD
1225 PM EDT Sun Aug 11 2024

Areas affected...eastern GA into SC and the coastal Plain of NC

Concerning...Heavy rainfall...Flash flooding likely

Valid 111625Z - 112225Z

SUMMARY...Thunderstorms over the Coastal Plain of NC/SC into
eastern GA are likely to result in scattered areas of flash
flooding. Rainfall rates of 1 to 1.5 inches in 15 minutes can be
expected.

DISCUSSION...Visible imagery at 16Z showed expanding cumulus along
the sea breeze extending from near CHS to the Outer Banks along
with the early onset of diurnal thunderstorms. The airmass across
the region remained very moist with 1.9 to 2.2 inch precipitable
water values noted on the CHS and MHX 12Z soundings. 850-300 mb
mean layer winds were near 5 kt at CHS and closer to 15 kt at MHX
from the WSW and while there was a greater degree of dry mid-level
air noted in sounding data compared to yesterday, very moist low
levels with surface dewpoints in the upper 70s to about 80 F will
be supportive of intense rainfall rates.

Thunderstorms will likely increase in coverage along the sea
breeze boundary through 18Z with additional development occurring
inland, closer to a slow moving front analyzed NE to SW across the
Southeast into the remainder of the afternoon. A lack of wind
shear aloft should limit cell organization, but cell mergers and
outflow interactions will result in brief upticks in cell
intensity. Greater thunderstorm coverage may occur across NC due
to increased lift along the base of an eastward moving upper level
trough currently located over the Upper Ohio Valley.

Rainfall rates of 1 to 3 in/hr are expected, but with 1 to 1.5
inch totals in 15 minutes driving a flash flood threat atop soils
that are saturated from recent heavy rain. 7-day rainfall totals
across the Coastal Plain are in excess of 10 inches from southern
NC through much of SC. High short term rainfall rates along with
storm totals of 2 to 4 inches, locally higher, are expected to
support scattered areas of flash flooding through the afternoon
and early evening.

Otto

...Please see www.wpc.ncep.noaa.gov for graphic product...

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

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

LAT...LON   36487584 35837537 34897564 33757759 32637931
            31848069 32188159 33278237 34158179 34867985
            35667797 36417675