014
AWUS01 KWNH 241837
FFGMPD
INZ000-ILZ000-MOZ000-242330-

Mesoscale Precipitation Discussion 0316
NWS Weather Prediction Center College Park MD
237 PM EDT Fri May 24 2024

Areas affected...Eastern MO...Central IL...Western IN

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

Valid 241835Z - 242330Z

SUMMARY...Ongoing moisture advection oriented perpendicular to a
stalled convergence boundary will likely spawn additional
thunderstorms for several more hours. Flash flooding is possible
this afternoon, especially in areas hit with repeated rounds of
thunderstorm activity.

DISCUSSION...18Z surface analysis shows a narrow convergence axis
orient W-E from northern MO and central IL into western IN. At
850mb an influx of theta-e ensued along with an increasingly
unstable environment. RAP mesoanalysis shows as much as
2,000-3,000 J/kg of MLCAPE along the southern periphery of
thunderstorms that have flared up along the surface trough. RAP
forecasts suggest that the 850mb flow overrunning this boundary is
likely to continue for several more hours, while at the same time,
the flow will overrun the ensuing cold pool that will further
enhance additional thunderstorm development. The 17Z HRRR shows
the potential for back-building convection north of St. Louis that
could result in excessive rainfall rates up to 2"/hr. While
soundings will also likely contain hail, the environment based on
effective bulk shear (40-50 kts) and effective SRH (100-200
m2/s2), suggest mesocyclones could help to enhance precipitation
rates as well.

This setup makes it ideal for congealing clusters of storms to
potential train and/or back-build for several hours. 1-hr FFGs are
as low as 1.5-2.0", which are within reach for the excessive
rainfall rates these storms can produce. As a result, flash
flooding is possible this afternoon with low lying areas and more
urbanized communities particularly more susceptible to flash
flooding.

Mullinax

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

ATTN...WFO...DVN...ILX...IND...LOT...LSX...

ATTN...RFC...MBRFC...NCRFC...OHRFC...NWC...

LAT...LON   40738745 39548738 38808806 38459020 38649160
            39429191 40099186 40509119 40638921