Subj : MESO: Nws Weather Prediction Center College Park Md
To   : wx-storm@lists.illinois.edu
From : COD Weather Processor
Date : Sun Jul 27 2025 05:47:38

AWUS01 KWNH 270547
FFGMPD
ILZ000-MOZ000-271000-

Mesoscale Precipitation Discussion 0808
NWS Weather Prediction Center College Park MD
143 AM EDT Sun Jul 27 2025

Areas affected...Far Northeast MO...Southwest to Central IL

Concerning...Heavy rainfall...Flash flooding likely

Valid 270543Z - 271000Z

SUMMARY...Dangerous and life-threatening flash flooding is
unfolding north of the St. Louis metropolitan area. Additional
very heavy rainfall is expected over the next few hours across
portions of far eastern MO through central IL.

DISCUSSION...The latest radar imagery shows a band of training
thunderstorms north of the St. Louis metropolitan area impacting
portions of Lincoln and Pike Counties in northeast MO, along with
Calhoun, Greene, Jersey, and Macoupin Counties in southwest IL.

This activity is currently producing rainfall rates of 2 to 3+
inches/hour, with some MRMS storm totals amounts so far of 5 to 6
inches, with the heaviest amounts in between Elsberry, MO and
Hamburg, IL.

This activity continues to focus along and generally north of a
surface trough as a mid-level vort center/trough approaches from
the west and interacts with it. Very moist and unstable low-level
flow ahead of this energy and along this surface boundary
continues to play a key role in facilitating the convection which
has become aligned in a general west/east fashion with the deeper
layer westerly steering flow.

The strong thunderstorm activity over the last hour has been
exhibiting some backbuilding characteristics which has only
exacerbated the cell-training concerns. Given the cooling cloud
top trends that have been noted over the last 1 to 2 hours, this
convection should certainly tend to persist for at least a few
more hours.

Additional rainfall totals of 3 to 5 inches will be possible at
least locally given the extremely high rainfall rates and the
cell-training concerns. Given the ongoing significant flash
flooding concerns north of St. Louis, these additional rains will
foster dangerous and life-threatening flash flooding impacts going
through the pre-dawn hours.

Orrison

....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=
DZ3fjg!6px_TEAiE-aU_BSUPfjOLjc_Q_SZ1PEVN33xLgI8A62sommvWL16Agy8WBxjIuGyCr9c=
Sr4FIfIqAQZ8VrcSiZ9s4rw$  for graphic product...

ATTN...WFO...ILX...LSX...

ATTN...RFC...KRF...MSR...TIR...NWC...

LAT...LON   39488992 39428900 39218836 38888840 38728906=20
            38689030 38759116 38929158 39159162 39369135=20
            39479078=20

=3D =3D =3D
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