A winter storm watch has been issued for a number of Chicago-area counties beginning Tuesday evening as forecasters say confidence is growing that the area could be hit by not one, but two rounds of snow.
The forecast remains fluid and snowfall projections are still uncertain as even a minor shift in the storm's track could make for dramatic changes, but a winter storm watch warns of as much of 6 inches or more in some locations.
The watch begins Tuesday evening for Grundy, Kankakee, Will and central and southern Cook counties in Illinois, along with Lake and Porter counties in northwest Indiana. It remains in effect through Thursday afternoon. Another watch is in effect for Newton and Jasper counties in northwest Indiana, which warns of the possibility for snow totals in excess of 8 inches.
Two rounds of snow are possible across parts of the Chicago area, with the first set to arrive Tuesday night through Wednesday morning. The second would then take place Wednesday night through Thursday, with a break possible throughout the day Wednesday.
Forecasters with the National Weather Service say that break makes it increasingly challenging to project snowfall totals "since they ignore compaction during and between the waves of snow." Areas along and southeast of Interstate 55 are currently expected to see the higher amounts of snow.
As the work week begins, warming temperatures are expected, with highs reaching into the 30s on Monday and then into the 40s on Tuesday, according to forecast models.
On Tuesday afternoon, a significant change is expected to hit the area, with a weather system potentially bringing heavy precipitation to the region.
That system will start out with rain, but as temperatures begin to cool it will transition to snow, and according to forecast models, there could be serious travel impacts caused by the storm, with mixed precipitation, snow or ice all possible, depending on temperatures and location.
Adding some uncertainty to the equation is another round of wintry weather that could arrive right on the heels of that storm Wednesday evening and into Thursday. According to NWS, "confidence is rising" that this second round will hit the Chicago area, at least in part, Storm Team 5 meteorologists stress that any change in the storm's path could have a large impact on those projections.
Either way, a sharp cut-off in snow is anticipated on the NW side of both systems, which could mean that some northwest Illinois suburbs may see little-to-no accumulation with either system.
Travel conditions will likely be hazardous in areas that do see snow with these two rounds, particularly during the morning and evening commutes on Wednesday and Thursday.
The NBC 5 Storm Team will continue to monitor the weather systems as they develop, and the latest information can always be found on the NBC Chicago app.