597
AWUS01 KWNH 260141
FFGMPD
NCZ000-SCZ000-GAZ000-260600-

Mesoscale Precipitation Discussion 0181
NWS Weather Prediction Center College Park MD
941 PM EDT Fri Apr 25 2025

Areas affected...Northern GA...Upstate SC...Western NC...

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

Valid 260140Z - 260600Z

SUMMARY...Progressive, but intense line moving through rugged
terrain poses a possible localized flash flooding concern through
early overnight period.

DISCUSSION...GOES-E 10.3um loop shows a rapidly cooling and
upstream expanding line of thunderstorms across northeastern GA
with additional cooling noted along the southwestern edge of the
older outflow boundary moving out of AL into western GA.  RAP
analysis supported by surface observations shows some remaining
elevated temperatures in the mid 70s to a few low 80s across the
northern portion of the state.  Tds in the mid 60s and steepening
lapse rates aloft continue to support a pocket of 1000-1250 J/kg
of CAPE along/ahead of the convergence line.  Additionally,
surface to boundary layer winds have backed and increased
orthogonality to the line to further increase convergence and
updraft strength. Deep layer moisture lags the instability axis
slightly, but confluent low level flow of 15-20kts, help flux
convergence with PWats reaching about 1.5".

RADAR trends show some northeast cell motions within the line,
especially further north to subtly increased heavy rainfall
duration, as such, rates of 1.5-2"/hr have already been estimated
across the northeast and spots of 2-3" are possible as the line
crosses the area.  Given complex terrain and lower FFG values, a
spot or two of exceedance suggest flash flooding is possible.
Also of note, the line is in the process of crossing the Atlanta
metro, which is also prone to such rates given impermeable
surfaces.  Otherwise, the progressive nature will likely limit
overall flooding risk to lower end and isolated to widely
scattered in nature through early overnight period.

Gallina

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

ATTN...WFO...CAE...FFC...GSP...MRX...

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

LAT...LON   35718287 35628228 34938165 34058166 33498243
            33138311 32838375 32828452 33058496 33768494
            34288456 35368357