National Weather Service-Chicago snowfall analysis illustrates Lake
Michigan's impact on Wednesday's storm totals here
National Weather Service meteorologist Mark Ratzer has generated a fascinating post-storm Chicago area snowfall analysis which illustrates just how much of an effect Lake Michigan's warmth had on area snow accumulations this past Wednesday. Though evaporative cooling--a process which removes heat as precipitation falls into a dry air and initially evaporates--permitted snow to reach into the city, lakeside accumulations were far less than those to the west---in the Fox Valley, for instance.
Here is a link to the snowfall distribution map:
http://www.crh.noaa.gov/lot/science/24nov2004/snowmap.gif
