Mesoscale Precipitation Discussion 0729
NWS Weather Prediction Center College Park MD
238 PM EDT Thu Jul 17 2025

Areas affected...Missouri into Indiana

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

Valid 171836Z - 180030Z

SUMMARY...Increasing convection along and south of an approaching
cold front will continue rest of the afternoon. There is a
likelihood for training, so scattered instances of flash flooding
are likely into the evening from southeast Missouri to southern
Indiana and western Kentucky.

DISCUSSION...Scattered heavy thunderstorms are developing in the
warm sector ahead of a cold front that has reached St. Louis and
Indianapolis. These are developing in enhanced moisture (axis of
2" PW) and instability (MLCAPE 2000-3000 J/kg). The heaviest
southern IL activity has had estimates of 2"/hr which can be
expected in this low shear environment (effective bulk shear is
20kt or less per the RAP).

CAMs including recent HRRRs and RRFS have additional development
farther north along the cold front which is currently over the St.
Louis metro. General upscale growth can be expected to continue
through the rest of the afternoon. The low level SWly inflow
around 15kt will help maintain activity and the Wly deep   layer
steering flow is parallel to the front and will support
repeating/training activity. Max totals of 2-4" can be expected in
three hours. Given the 3hr FFG is 2.5" or less, scattered flash
flooding can be considered likely.

This activity is along a greater west-east axis so further MPDs
can be expected, particularly downstream.

Jackson

ATTN...WFO...ILX...IND...LMK...LSX...PAH...SGF...

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

LAT...LON   39138972 38908722 38678634 37538618 36948692
            36928986 36969114 37369194 38479166 39089105