As of Friday evening the steak of days without measurable (0.1 inch) snow at Chicago's official O'Hare International Airport observation site had reached 278 - the last measurable snow occurring back on March 4th. Chicago's record longest consecutive day period without measurable snow (since 1871) was 280 days set back in 1994. We have two chances to snap the current streak this weekend with back to back low pressure systems just 36 hours apart passing just to our south. If a measurable snow does not occur at O'Hare, the old record of 280 days will be tied Sunday and a new record probably established Monday.
It looks like the best chance of measurable snow will be with the first Low pressure center generating a rain/snow mix Friday night mainly along and north of Interstate 88 - changing to wet snow before heading out over Lake Michigan and ending Saturday forenoon.
The second low pressure system should pass to the south of Chicago Sunday - spreading rain over the metro area. As that system pulls away to our east, rain could briefly change over to wet snow before ending Sunday night.