Lake effect: What is it? Does it only happen in Central New York?

Weather
Waves crashing at the Lake Ontario lighthouse

(WSYR-TV) — What is lake effect? Many of us that have lived in Central New York have a love/hate relationship with the unique weather event.

If you’re new to the area, you might not know what it is. Perhaps you might have forgotten what it is. Hopefully, this article can clear up some questions you might have.

What is lake effect?

The water in the Great Lakes warms up in the summer. As fall approaches, cool air comes our way from Canada. As that cool air crosses the warm waters of the Great Lakes, the air over the lake rises (in essence it’s heated by the warm lake waters) That rising air leads to clouds and eventually precipitation.

Image Source: NOAA National Weather Service

The lake effect precipitation can fall in the form of rain or snow, depending on the temperature near the ground.

Meteorologists keep a close eye on temperatures about 5,000 feet above the lake waters. There is a magic temperature difference that must be met to begin the lake effect process.

I won’t go into all of the science, but typically when a temperature difference between the lake water and the air temperature at 5,000 feet reaches 13°C (55.4°F) you’re in the lake effect business.

As long as there is open water on the Great Lakes, you can have lake effect.

That’s why as ice cover increases on the lakes in the cold of winter, the lake effect snow will decrease.

Lake Erie typically freezes over in the winter, so Buffalo’s snow-making time usually is in the first half of winter. Lake Ontario typically does not freeze over.

One reason for this is the depth of Lake Ontario approaches 800 feet just north and northeast of Oswego.

There usually is open water, which means as long as we have cold enough temperatures 5,000 feet above the lake we can have clouds and precipitation.

It’s not just a Central New York thing

It’s not just something we see here in Central New York. Yes, lake effect precipitation is most common around the Great Lakes, it can form off of the Great Salt Lake in Utah.

It’s been known to happen in Labrador, Canada. Japan. Cape Cod (where it’s called ocean effect).

It is very localized, leading to changeable weather

The crazy thing (or one of them) is that lake effect, whether it’s rain or snow, is very localized.

That’s not so much of a problem with rain. But in the winter, you can go from sunny skies to a blinding snowstorm in a matter of a few miles drive.

Why is that?

Well, it has to do with the way lake effect forms. I wrote about how the lake heats the air resulting in clouds and precipitation.

The clouds and precipitation don’t stay just over the lake. They move over land. They are moved by wind.

The clouds and precipitation form into narrow bands that run parallel to the wind. In other words a west wind will produce a west to east oriented band of lake effect weather which will impact areas east of the lake. Picture Lake Ontario for this example.

A north wind (wind coming from the north) will create multiple bands of lake effect precipitation south of the lake.

What are some things you would like to know about lake effect precipitation? Shoot me an email with your question(s).

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