snippets from KLOT
Saturday morning, snow
appears poised to spread quickly from south to north across much
of northern Illinois and far northwestern Indiana and last through
the remainder of the day. The steadiest snow looks to remain
within a 10-12 hour period from roughly noon Saturday to midnight
Sunday, with snow rates of 0.5"/hr prevailing. Heavier snow rates
approaching 1"/hr may develop within transient frontogenetical
bands as well as along the Illinois shoreline of Lake Michigan
where sufficiently cool temperatures will make the marine airmass
unstable within a favorable northeasterly wind trajectory. After
midnight, snow will taper from west to east except along the Lake
Michigan shore where lake enhancement will continue through
daybreak Sunday.
Snow ratios look to start near 10:1 Saturday afternoon and increase
toward 18:1 Saturday night as the low-level temperature profile
cools.
The highest confidence area for hitting
warning-level impacts (e.g. where travel would be discouraged
entirely) is actually in Lake County (IL), eastern DuPage County,
and all of Cook County where there appears to be an increasing
chance that lake-enhanced snow rates of 1"/hr will overlap with
blustery northeast winds, leading to low visibility.