I don't normally post long AFD's but since this thread has been somewhat quiet thought this was a good read on this event out of LOT:
CONFIDENCE CONTINUES TO INCREASE THAT A PERIOD OF STEADY, LIGHT SNOW
WILL COMMENCE FRIDAY NIGHT AND LAST THROUGH MUCH OF SATURDAY AS THE
DIFFLUENT RIGHT-ENTRANCE REGION OF AN UPPER-LEVEL JET STREAK STREAMS
OVERHEAD. WHILE SNOWFALL RATES ARE NOT EXPECTED TO BE "HEAVY"
(GENERALLY 0.1-0.3"/HR), SNOW WILL NEVERTHELESS BE STEADY AND
GRADUALLY PILE UP WITH TIME. FORECAST LOW-LEVEL THERMAL PROFILES
DEPICT AN IMPRESSIVELY DEEP AND SATURATED SNOWFLAKE GROWTH ZONE FROM
THE GROUND TO NEARLY 15,000 FEET UP, WHICH WILL ALLOW FOR VERY
FLUFFY SNOW RATIOS IN THE NEIGHBORHOOD OF 20:1 TO 25:1, IF NOT
HIGHER. AN ENSEMBLE OF SHORT-TERM HIGH RESOLUTION MODELS ALSO
DEPICT A SWATH OF 0.15-0.25" OF QPF THAT (WHEN COMBINED WITH THE
AFOREMENTIONED FLUFFY RATIOS) WILL LEAD TO A WIDE SWATH OF 3-5"
SNOW ACROSS MUCH OF NORTHERN ILLINOIS. LOCALLY HIGHER AMOUNTS
WOULD CERTAINLY BE POSSIBLE IF RATIOS OR PRECIPITATION AMOUNTS END
UP HIGHER THAN CURRENTLY ANTICIPATED. THE EXACT LOCATION AND
SOUTHERN EDGE OF THE HIGHEST SNOW TOTALS WILL BE OPPORTUNITIES FOR
FURTHER REFINEMENT IN LATER FORECAST PACKAGES (AND IT SHOULD BE
SAID SOME OF THE NEWEST MODEL RUNS ARE PAINTING AREAS NEAR I-80
WITH THE HEAVIEST AMOUNTS), BUT CONFIDENCE IS HIGH THAT SNOW WILL
FALL ESPECIALLY BETWEEN 6 PM FRIDAY AND 6 PM SATURDAY. BE PREPARED
FOR SNOW-COVERED ROADWAYS AND LONGER TRAVEL TIMES.