589
ACUS11 KWNS 131544
SWOMCD
SPC MCD 131543
INZ000-ILZ000-IAZ000-131945-

Mesoscale Discussion 2258
NWS Storm Prediction Center Norman OK
0943 AM CST Sat Dec 13 2025

Areas affected...far southeast IA...central IL...amd west-central IN

Concerning...Heavy snow

Valid 131543Z - 131945Z

SUMMARY...A band of moderate to heavy snow with bursts of rates
around 1 inch per hour expected through around 20Z.

DISCUSSION...The latest mosaic radar data and surface observations
depict a swath of moderate to locally heavy snow spreading eastward
across eastern IA, central IL, and western IN. As strengthening DCVA
preceding an embedded midlevel perturbation (evident in water-vapor
imagery) continues spreading eastward into IL over the next couple
hours, an uptick in the coverage of heavy snowfall rates can be
expected. This increase should generally focus in an east/west
corridor extending from southeast IA across central IL into
west-central IN through around 20Z -- when the aforementioned lift
overspreads a cold, deeply saturated profile with a favorable
isothermal layer below 700 mb for aggregation. Snowfall rates of
around 1 inch per hour are expected beneath the core of the heaviest
banding, with bursts of locally higher rates possible.

..Weinman.. 12/13/2025

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...IWX...IND...LOT...ILX...DVN...

LAT...LON   39398761 39728927 40099058 40519152 40969185 41349183
            41669154 41669096 41338964 40968807 40738664 40418605
            39778602 39338653 39398761