The only predictable thing about Ithaca’s weather seems to be its unpredictability. However, according to Cornell professors, there is not one exact reason behind these fluctuations. In fact, the weather patterns of the Northeast are caused by an amalgamation of factors that often result in an April week beginning with warm sunshine and ending in a snowstorm.
Prof. Arthur DeGaetano, earth and atmospheric sciences, director of undergraduate studies for atmospheric sciences, explained that Ithaca’s latitude plays a major role in its weather variation. “[Ithaca is] in the middle latitudes of the earth, and the middle latitudes tend to be the most variable,” DeGaetano said.
Ithaca receives winds from both the North and South poles, located on the dividing line between the frigid winds from the Arctic and warm weather from the tropics. Ithaca being within the dividing line of these two big weather systems results in these large temperature fluctuations, as the systems try to equal each other out.
According to DeGaetano, transitional seasons in Ithaca such as spring cause jarring weather patterns because that is when the difference in temperature from both weather systems is maximized.
There are, however, other cities at the same latitude as Ithaca with different weather patterns, according to Prof. Flavio Lehner, earth and atmospheric sciences. Rome, Italy is located at the same latitude but is generally warmer than Ithaca, with less extreme weather fluctuations. Lehner explained that this substantial difference is due to its distance from the ocean.
“The ocean is a stabilizing influence,” Lehner said. “It’s a big mass of water with a high heat capacity so temperature doesn’t change as much. [Ithaca doesn’t] have the stabilizing influence from the ocean.” The center of Rome to the Amalfi coast is around 172.741 miles, while the distance between Ithaca and Ocean Beach is around 212.89 miles in the southeast direction. This allows Rome to have weather stabilization to a greater extent than Ithaca.
“Sometimes you can stay at the same latitude and find the same climate but sometimes it’s different because of ocean currents and wind currents,” Lehner said.
DeGaetano said that mountains can also be a weather-stabilizing force.
“The other thing that makes Ithaca a bit different is that we’re kind of far away from mountains,” DeGaetano said. If you think of a place like Denver, where it’s dry over the winter, a lot of that has to do with where they sit in relation to the mountains. Since we don’t really have that here, that helps us be more variable than a place like Denver.”
Distance from both the ocean, substantial bodies of water like the Great Lakes, and mountains causes significant variability in Ithaca weather. The combination of no stabilizing forces, with Ithaca’s latitudinal location causes an increased degree of weather fluctuation, which may actually get worse in the future, according to DeGaetano.
Ithaca’s weather is set to become a lot more variable with climate change. DeGaetano explained that jetstream —a track in the atmosphere where the winds are strongest — acts as a wall that separates the cold air of the north and the warm air of the south. The larger the difference in temperature of the north and the south, the stronger the jetstream is. This means that if the temperatures coming from the North Pole are similar to those coming from the South Pole, the jet stream becomes weaker.
As the air from the north, coming in from the Arctic becomes warmer, the contrast between the north and south winds dwindles. This means the jetstream becomes weaker, and the waves within it increase, causing more variability within the winds as these jetstreams act as a fence between the cold winds of the north and the warm winds of the tropics.
These waves within the weakened jetstream, allowing either the cold air to come down and the warm air to move up further than it already does. “The bottom line is there’s evidence that under climate change, we do see more variable weather like that, especially with changes in temperature,” DeGaetano said.
Because of these waves within the jetstream, weather in places like Ithaca, whose latitude and distance from the ocean already cause more variable weather, will become even more volatile.
The warming of areas up north like the Arctic will have an effect on places as away as Ithaca.
“I think the bottom line is there’s evidence that under climate change, we do see more variable weather like that, especially with changes in temperature,” DeGaetano said.