How Often Do Conditions Develop To Produce Lake Effect Snow?

One of the many variables to produce lake effect snow is a significant enough difference between the water temperature and the temperature 5000 feet off the ground. Typically you need a difference of at least 13 degrees Celsius. So if the water temperatures is say 50 degrees F (10 Celsius) and the air temperature at 5000 feet is 27 degrees (-3 Celsius) that would be the lowest difference to allow evaporation and eventually the condensation of water vapor to occur as the colder air moves over the warmer lake.  The greater the difference, the faster the air rises and the more unstable the lake effect snow becomes.

This satellite image shows the uniform bands of lake effect cloud cover off every Great Lakes with a strong northwest wind. Notice the lack of cloud cover on the windward (western) side of each lake. The condensation of the water vapor occurs more than 20 miles offshore as the warm water vapor rises into the colder air aloft. 

How often does a difference of 13 degrees Celsius occur in northern Ohio in the prime lake effect snow time of the year?

I cross referenced the Lake Erie water temperature and the temperature at 5000 feet for five straight winters (Nov 2014 through January 2019). Each instance where the difference meets of exceeds 13 degrees Celsius I shaded that day in blue.

We average about four instances where the Lake Erie/5000 foot temperature difference exceeded 13 degrees (high enough for lake effect snow) each winter between 2014 and 2019.  How many of these produced significant snow?  More on that later.