666
AWUS01 KWNH 061947
FFGMPD
NCZ000-SCZ000-GAZ000-070130-

Mesoscale Precipitation Discussion 0577
NWS Weather Prediction Center College Park MD
347 PM EDT Sat Jul 06 2024

Areas affected...Eastern Georgia, South Carolina, and South
Central North Carolina

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

Valid 061947Z - 070130Z

SUMMARY...Convection developing across the Carolinas and Georgia
may cause flash flooding as rainfall rates approach 3 inches per
hour.

DISCUSSION...An approaching slow-moving cold front with some
meager right entrance region support from a jet streak over the
Ohio Valley is providing the forcing for widespread convective
initiation across the Southeast this afternoon. The strongest
storms just south and southeast of Columbia, SC have produced
rainfall rates to 2.5 inches per hour. SPC mesoanalysis shows
PWATs as high as 2.4 inches across east central Georgia, with
SBCAPE values over 4,000 J/kg across coastal Georgia and far
southern South Carolina. Southwesterly flow ahead of the cold
front is drawing that abundant moisture and instability northeast
into the front...albeit slowly. The result has been storms all
across the Southeast that have been easily able to exceed 2 inches
per hour rates, while also moving, merging, and organizing very
slowly...lengthening the amount of time any one area is subject to
heavy rainfall.

Soil moisture conditions have been very dry across this area in
recent weeks, with very low river levels. While this is certainly
better than the alternative...areas where there are more clay
soils become more hydrophobic when they`re very dry, which
initially supports increased runoff from the heavier rains.
Thus...urban and small stream flooding are the primary threats
today across this area...whereas those communities that see
lighter rainfall will be largely very beneficial. Thus...flash
flooding appears only possible in the areas that see extended
heavy rainfall.

CAMs guidance has certainly been slow with developing the
convection, with none of them having a good handle on what has
developed so far. With the continued advance of the cold front
towards the southeast...the front will become increasingly
important for helping the storms organize into a line where
training and backbuilding become increasingly common. While this
is more likely in northern and western portions of the highlighted
area (NC/SC)...storms capable of heavy rainfall are expected to
continue area-wide through the afternoon.

Wegman

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

ATTN...WFO...CAE...CHS...FFC...GSP...ILM...JAX...RAH...

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

LAT...LON   35718002 35657942 35227866 33837970 32878058
            31638144 30988248 31408297 31748294 31948324
            32008345 32338347 33158291 34338230 35398082