574
AWUS01 KWNH 242213
FFGMPD
ILZ000-MOZ000-ARZ000-250330-

Mesoscale Precipitation Discussion 0317
NWS Weather Prediction Center College Park MD
612 PM EDT Fri May 24 2024

Areas affected...Southern MO...Northern AR...Southern IL

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

Valid 242210Z - 250330Z

SUMMARY...Robust thunderstorm activity flaring up along a
prefrontal surface trough and an approaching cold front may
congeal over parts of the highlighted region this afternoon and
evening. Hourly rainfall rates could top 2"/hr and may result in
areas of flash flooding.

DISCUSSION...Satellite and Doppler Radar depicted healthy and
severe-warned cells tracking through the heart of Missouri. These
storms are forming along a surface trough that also has ties to
the ongoing convection that has caused flash flooding north and
St. Louis. Meanwhile, a cold front is also triggering
thunderstorms with the cells marching towards southern MO thanks
to persistent westerly 850-300mb winds aloft. The environment out
ahead of the cold front is quite unstable with RAP mesoanalysis
sporting over 3,000 J/kg of MLCAPE in central MO. Meanwhile, PWs
are  close to 1.5" in southern MO with a steady influx of
low-level moisture being directed at the Ozarks and along the
surface convergence zone. RAP mesoanalysis depicts as much as
30-40 kts of effective bulk shear within the atmosphere which will
help to sustain these storms into the early evening hours. In
terms of soundings, the RAP shows warm cloud layers close to
10,000ft deep, but mean cloud layer winds are at 30 knots which
should keep storms moving along initially.

As the two boundaries collide, and outflows from the initial
storms in central MO drift south, this will give storms the
opportunity to congeal into an organized cluster of storms. This
setup will allow for storms to generate excessive rainfall rates
of 1.5-2"/hr as they track across southern MO. These storms could
track as far south as the Ozarks of northern AR and across the MS
River into southern IL based on probabilistic guidance from the
18Z HREF. Soils in the area are not too saturated or too dry, so
that will help to limit the areal extent of potential flash
flooding. That said, segments where storms congeal and persist
over a given area for 2-3hrs at a time could lead to flash
flooding in low lying, poor drainage areas.

Mullinax

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

ATTN...WFO...LSX...LZK...PAH...SGF...TSA...

ATTN...RFC...ABRFC...LMRFC...MBRFC...NCRFC...NWC...

LAT...LON   38499153 38208990 37459000 36769090 36339180
            36159330 36389435 37369389 38209273