It is beginning to look like a late winter, early spring snowstorm will affect the Aurora area on Tuesday. Models have come into better agreement today on a track, but there is still some spread. This is a winter that has seen the majority of its snow systems in the latter half.
A large upper level low pressure will dig southeastward out of the Pacific northwest and push southeast across the plains the next couple of days. This will eventually ride into southwestern Illinois on Tuesday. Unlike most northern, clipper like systems, this one looks very intense, with the ability to draw moisture northward from the Gulf of Mexico. This will be possible as it is aided by a small trough moving out of the southwest. As these combine, they are likely to lay down an impressive band of snowfall. 6-12 inches of snow are not out of the question in the hardest hit areas.
As of now, areas south of Interstate 80 and west of Interstate 39 stand on the best chances to see over 6 inches of snow. The NAM model has been consistently placing the heaviest snow over the I-80 to I-88 corridor. The European model has also generally favored a northern track. The Global Forecast Model and Canadian models kept the system mostly to the south through last night. However, the Global model continues to inch the system further north today. This trend will have to be followed closely as better agreement on this northern track may lead to a winter storm watch, from The National Weather Service, being issued for parts of the area as early as tomorrow. Even an average track somewhere in the middle would look to put several inches of snow down areawide. Stay tuned for further updates as the track becomes clearer.