Mesoscale Precipitation Discussion 0161
NWS Weather Prediction Center College Park MD
143 PM EDT Wed Apr 23 2025

Areas affected...southeast NC & northeast SC

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

Valid 231741Z - 232341Z

Summary...Organized thunderstorms are forming across southeast NC
and coastal SC with some showing signs of backbuilding/limited
movement.  Hourly rain totals to 2" with local amounts to 4" are
possible, which would be problematic in urban areas.

Discussion...A frontal boundary lies across the region, oriented
east-northeast to west-southwest, with a weak/elongated wave near
Lake Waccanaw NC, which has shifted southwestward since 12-15z
based on surface observations.  Precipitable water values are
~1.3-1.4".  ML CAPE across the region appears to be drifting
southwest, with values of 500-1500 J/kg on both sides of the
front, which should increase another 500 J/kg or so this
afternoon.  Effective bulk shear of 25-35 kts is organizing the
storms.

The 12z HREF indicates that the heavy rain threat increases
through the afternoon, with the highest rain rates shifting
southwest with time, which fits recent trends in the ML CAPE pool
and RAP mass fields regarding the weak frontal wave's expected
future movement.  Recent backbuilding on radar is expected to
continue over the next several hours.  Hourly rain totals should
maximize in the 2" range, with local amounts to 4" possible.  The
guidance shows a reasonable signal for heavy rain in this region,
with a similar signal.  Soils are sandy in this region, which when
combined with minimal rainfall over the past couple of weeks has
led to high flash flood guidance values.  Any issues are expected
to be urban, given the expected hourly and overall totals.

Roth

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

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

LAT...LON   34977727 34687693 34307759 33797790 33807835
            33687873 33107917 33127980 33988006 34647916
            34887820