Warm lakes and cold Canadian winds create the perfect (snow) storm.
In the early winter (from November to January), there is a chance for large winter storms because lakes help to produce more snow. When cold dry winds from Canada blow over the Great Lakes, the winds pick up moisture that is evaporating from the lakes. That moisture is turned to snow and then dumped on some poor city. This is called Lake Effect Snow and it occurs when there isn’t any ice on the lakes. As soon as the lakes freeze over, the lake effect snow season is over.
You might have heard stories of snow storms where feet of snow are produced in a few days. The lakes enhance the snowstorm by providing more moisture to the system. Cities along the Great Lakes are most effected. However, Buffalo, NY has been a sweet spot for lake effect snow in recent years.
So, be on the look out for mega-snow storms early in the winter season. Without ice to capped off the moisture, there will be more precipitation.
Rain is also increased by lakes and oceans, but the amounts are not as much as the snow. This is because 1 inch of rain is equal to 10 inches of snow, according to the National Weather Service. (That ratio depends on the temperature and the fluffiness of the snow, by the way.)
No matter how you measure it, increased precipitation by lakes is snow joke and will make one wish for an early spring.