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      Great Lakes water levels decrease

      It may be hard to tell with the naked eye, but the water levels of the Great Lakes are lower than average.

      Take Lake Superior, its long-term average from 1918 to 2011 was 601 feet, but it's currently a foot and a half below that number.

      Some of the other Great Lakes are experiencing around a two-feet decrease in levels.

      "When we look ahead 20 to 30 years, the level of Lake Superior, Lake Michigan, and Huron will be likely lower. That doesn't mean lower than today; just on average it will be lower. We will still see the ups and downs we have seen in the past," said John Levin, International Joint Commission with the Great Lakes.

      So what causes water levels to decrease?

      Well, a couple of factors, starting with the lakes having warmer than average temperatures. Warmer temperatures lead to more evaporation or loss of water. Plus the lack of ice cover doesn't help either.

      However, that's not the only factor.

      "We call them synoptic patterns here--large scale low pressure systems. So we just haven't had that many more through. So we are not bringing in precipitation from other areas and depositing them into Lake Superior," said Keith Cooley, Meteorologist.

      Officials say fluctuations in levels can come in cycles of every couple of decades to every couple of years.

      In order to regain some lost water, we need a lot more precipitation into the lakes.