439
AWUS01 KWNH 162204
FFGMPD
KYZ000-INZ000-ILZ000-170330-

Mesoscale Precipitation Discussion 0279
NWS Weather Prediction Center College Park MD
604 PM EDT Fri May 16 2025

Areas affected...Much of Kentucky...Adj Southern IL/IND...

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

Valid 162200Z - 170330Z

SUMMARY...Individual cells likely to expand and become more
linearly oriented, tracking through areas already saturated.
Additional 2-3" totals (in 1-3hrs) over the 1-3" from this
morning, may result in scattered incidents of flash flooding into
early overnight period.

DISCUSSION...Initial cluster of super-cells is tracking through S
IL entering western KY at this time, with additional development
along the unstable areas surrounding them.  Further expansion of
the cluster is expected over the next few hours as cells continue
to march through broad nose of 30-40kt southwesterly LLJ.
Environment across western and central KY has nicely rebounded
with temperatures into the mid 80s over upper 60s/low 70s Tds,
while insolation was limited as dense high-CB anvils obscure the
ground, instability has built back to well sufficient levels to
maintain strong buoyancy through the late evening/early overnight
period as cells rapidly race eastward.   Strong moisture flux into
the broad super-celll updrafts have increased rainfall efficiency
over the last few hours with quick 1-1.5" sub-hourly totals
estimated and some .75-1" totals noted upstream in SE MO.

Initial convection will continue to expand and feed along the
eastern edge of the LLJ with 1.5" total PWats feeding in, but
overall the LLJ will narrow and veer ever so slightly, to become a
bit more oblique to the outflow boundaries and allow for
isentropic ascent/convergence along the flanking lines.  Deep
layer steering, while very strong and mean winds over 60kts, will
slowly orient a bit more parallel to the updrafts supporting some
short-term training of the flanking cells.  18z HRRR 15-minute
rain totals occasionally reach 1.25-1.5" with the line as it
progresses and as such spots of 2-3" are expected (generally
aligning with 20-21z WoFS 50th to 90th percentile totals).  Slow
southward propagation will expose much of western and central KY
to this additional heavy rainfall.  This is of greater concern
given the 1-3" totals that fell this morning.  NASA SPoRT 0-40cm
soil ratios got as high as 80-85% and FFG values reduced to less
than 1.5"/hr across much of the area of concern with spots below
.75"/hr into the more rugged terrain of central to eastern KY.

Additionally, secondary development is probable along the cold
front that has lagged the initial development with some continued
heating and return moisture/instability flux through the MS River
Valley.  Additional upstream development, may further aid
scattered repeating, further exacerbating any flooding conditions.
  So all considered, while severe weather is primary threat,
especially across the next few hours; heavy rainfall will present
sufficient totals to result in possible scattered incidents of
flash flooding as well.

Gallina

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

ATTN...WFO...ILN...JKL...LMK...PAH...RLX...

ATTN...RFC...LMRFC...OHRFC...NWC...

LAT...LON   38728491 38528337 37868269 37288308 37048399
            36878565 36758699 36678874 37108912 37648864
            38148754 38538625