Mesoscale Precipitation Discussion 0653
NWS Weather Prediction Center College Park MD
1020 PM EDT Fri Jul 11 2025

Areas affected...Central Missouri to Central Illinois...

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

Valid 120220Z - 120700Z

SUMMARY...Diminishing flash flood threat as squall line begins to
forward propagate.  However, a few hours with ample moisture and
remaining unstable air mass will support 2"+/hr rates and spots up
to 3" and possible.

DISCUSSION...GOES-E 10.3um IR and RADAR animations show the long
mostly squall line is starting to show outflow boundary pressing
southeastward, increasing perpendicular forward propagation
reducing duration of heaviest rainfall and all but eliminating
internal cells repeating along the squall axis.  A small
inflection in the line near Macon county, MO is has some increased
intersection/mergers as northern edge is upstream developing or
effectively back-building into the southern flank, generally near
the highest remaining pool of unstable air which remains about
3500-4000 J/kg.  This also matches with increased ageostrophic
outflow given a small kink in the upper-level jet streak
maximizing right entrance ascent profiles as well.  Deep layer
moisture axis is nearly aligned with the squall line and low level
inflow is nearly parallel from 850mb with surface to 925kt inflow
still fairly oblique in ascent angle too.

Given the strength and available moisture, sub-hourly rates/totals
over 2" will remain for a few more hours before slowly diminish as
the squall moves into lower moisture over the Ozark Plateau and
into southern IL.  Backsheared mid-level shield precipitation will
likely allow for additional moderate rainfall with spots of 2-3"
totals over the next few hours; and while the FFG values are also
increasing further south and east, isolated incidents of flash
flooding remain possible though reducing with time. 

Gallina

ATTN...WFO...DVN...EAX...ILX...LSX...SGF...

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

LAT...LON   40998995 40968933 40648880 40238855 39598871
            39058926 38688995 38429054 38049151 37929267
            38469375 38839396 39219365 39959195 40429086