As someone who lives in Southwestern Ontario and get hit from the weather coming from Detroit I can tell you that winds 80% or the time come from the southwest and flows generally to the northeast. The second most common direction that the winds come from is the northwest heading southeast ... during winter it accounts for all those damn snowsqualls that hits my city.
Then you add in the common weather systems like Alberta Clippers and Colorado lows - both fast moving storm systems that hit fast, dumps tons of snow and rain ... and leaves just as fast.
And of course those weather systems that hit Detroit... come from Chicago...
Also a great source for watching weather patterns is the NOAA ..... It you watch the loop of the weather systems you can see the patterns.
http://www.srh.noaa.gov/ridge/Conus/index_loop.php