Mesoscale Precipitation Discussion 0810
NWS Weather Prediction Center College Park MD
528 AM EDT Sun Jul 27 2025

Areas affected...North-Central to Eastern MO...Southwest to
Central IL

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

Valid 270928Z - 271400Z

SUMMARY...Concerns for locally dangerous and life-threatening
flash flooding will continue through the early morning hours as
additional heavy rainfall impacts portions of north-central to
eastern MO through southwest to central IL.

DISCUSSION...The latest radar and satellite imagery shows multiple
bands/clusters of very heavy showers and thunderstorms continuing
to impact areas of north-central to eastern MO and into areas of
west-central IL. This includes embedded areas of slow cell-motions
and cell-training, with some of this getting very close to the St.
Louis metropolitan area.

Rainfall rates with the ongoing areas of convection continue to be
as high as 2 to 3+ inches/hour, with some MRMS-derived event storm
totals from overnight now upwards of 8 to 10+ inches in between
Elsberry, MO and Hamburg, IL.

This activity continues to focus along and generally north of an
outflow boundary as a mid-level vort center/trough gradually
transits the region from west to east. Very moist and unstable
low-level flow is overrunning the convectively-enhanced cold pool,
with radar imagery showing recent development farther west over
areas of north-central MO around the western flank of the vort
center. Backbuilding convection continues to be noted which is
continuing to reinforce concerns in the near-term for
cell-training.

Some of the latest hires model guidance suggests the ongoing
convection may linger past dawn and continue at least through the
early morning hours. The latest satellite trends depicting cooling
convective cloud tops over north-central and eastern MO would
certainly support this idea.

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, these additional rains will foster additional
concerns for dangerous and life-threatening flash flooding impacts
early this morning.

Orrison

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

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

LAT...LON   40259012 39888931 39108921 38688941 38349001
            38389091 38959238 39439330 39759360 40059311
            39919172