(SYRACUSE, NY)- A breeze can be refreshing on a hot summer day. In March though, it brings more of a chill.
During the spring and summer, Lake Ontario can generate a local breeze of it’s own. It happens in the midday or early afternoon when the land becomes warmer than the water. The warm air over the land rises (because it’s less dense, the molecules are fewer and further apart) and gets replaced by the cooler air near the lake.
We have the potential to see this in the short term forecast. We’re in a warming pattern through much of the work week. High temperatures will be well in the 60s to near 70 most of this week!
Our dry air mass is quicker to heat up than the 395 cubic miles of water that’s in Lake Ontario. This is where a concept called ‘specific heat’ comes into play. It is measured as the amount of energy to warm one gram of a substance by one degree Celsius. The specific heat value for the water is larger than the air. In other words, it takes a lot more energy to heat it up the water of Lake Ontario than the air over us.
The average temperature of the water on the eastern shore of Lake Ontario the first day of Spring is between 32° and 38°.
Air always flows from high to low pressure so if you have an area of high pressure over the lake and low pressure above the land adjacent to the lake, the cooler air over the lake has no choice but to blow inland. The lake breeze typically cools areas significantly within about 10 miles of the lake shore. The bigger the temperature difference between the lake and land, the stronger the pressure gradient and farther the lake breeze will extend inland.
For example, you’ll notice on a weather map on days a lake breeze occurs that areas near the shoreline, like Oswego and Pulaski have a wind out of the west while the wind direction in Syracuse is out of the south. You’ll also notice temperatures in Syracuse end up warmer because we don’t have the cooler water source the size of Lake Ontario close enough to cool us down.
A lake breeze forms easily when we have air temperatures in the 40s and water temperatures in the 30s but also when we have light winds in the forecast. If there’s a strong prevailing, regional wind greater than 10 mph, then the lake breeze will be prevented from developing. In this case, areas downwind of the cooler lake will feel the cooler air simply because of the general wind flow and not a lake breeze.