Heavy snow “lines-up” over Lake Michigan headed south into northwest Indiana overnight – very dangerous travel across northwestern Indiana

This was while getting off at the Jackson Red line station, downtown Chicago

The Weather radar Mosaic below depicts north-south-oriented “corridors” or “bands” of snow lined up over Lake Michigan heading south into northwest Indiana – dumping heavy lake-effect snow over portions of northwest Indiana. Under the heavier bands, 2 or three-inches of snow per hour could fall with totals reaching a foot in some locations where repeated surges hit time after time tonight into Wednesday morning. Travel across northwestern Indiana will be extremely difficult tonight into Wednesday morning as the snow piles up – with winds gusting over 30 miles per hour out of the north-northwest, there will be considerable blowing and drifting with near zero visibility at times.

It is an unusual setup over the lake that is creating these “corridors” or “bands” of snow. Strong “off-shore” northwest winds prevail along the Illinois/Wisconsin shoreline, while north to slightly northeast winds prevail along the Michigan shoreline. This combined with the air actually rising over the warmer waters (35 to 40-degrees) compared to readings in the teens and 20s along and inland of the adjacent shorelines, enhances the dual off-shore flow, causing convergence and lift over the lake, resulting in the convective “bands” or “corridors” lining up out over the lake – the strong northerly flow the length of Lake Michigan driving the snow-bearing clouds inland where they deposit their snow loads.

Note another interesting feature on the radar mosaic below…the bands of snow forming over southern Lake Huron and flowing south-southeast across Lake Erie, depositing heavy lake-effect snow over northeast Ohio and the Cleveland area.

Central Great Lakes sector loop