First Alert Weather In-Depth: Spring Lake Effect

ROCHESTER, N.Y. (WHEC) — We talk about the macroclimate and the microclimate. This is really the comparison of the big picture to the little picture and we can see illustrated today.

Right now there Is a lot of warm air that is coming into the Great Lakes. That is due to a warm front and a good example of that big picture. But in the microclimate look at the difference across Western New York. This is evident when comparing the town of Greece, where the temperature is only at 54 degrees, and then south to Dansville. The temperature there is approaching 70. So why the big difference in the temperature?

One of the main driving factors is the spring lake effect. But what is the mechanism for this to happen? Right now the water temperature in Lake Ontario is only about 40 degrees. As a result, the air right over Lake Ontario is very chilly. The cooler air is heavier and denser and when we have light winds across the area that cold air is going to move in one direction or another. Usually, it moves inland and replaces the warmer, less dense air. That will be a significant difference in the temperature we will see over the next couple of days. Expect a range of temperatures from the lakeside communities, where it will stay in the 50s, but then communities to the south will be well into the 60s and 70s.

So lake effect happens year-round, but it’s just a little less dramatic compared to the winter season.