Hearts were warm this Valentine's Day, but the same couldn't be said for Chicago's weather.
As if the past several days of brutal cold and extreme temperatures weren't enough, Sunday set a record for the unprecedented cold, according to NBC 5 Storm Team meteorologists.
The high temperature was just 4 degrees, breaking the previous record of 8 degrees, which was set in 1943. A cold Valentine's Day in Chicago isn't that rare, though: Temperatures dropped to -2 degrees last year.
This year, winds chills were as low as 30-degrees below zero in some locations.
But what's causing all this cold?
During the winter, a mass of cold air forms over the North Pole and the Arctic Circle because of the fact that no sunlight shines on that area during the winter months. A stream of air called the “polar night jet stream” keeps that cold air in place, in what amounts to a large circle of air over the top of the globe.
When “sudden stratospheric warming” occurs, the potential exists for that “polar night jet stream” to be disrupted in a big way, and that is what is happening right now.
On top of the bone-chilling temperatures, get ready for even more snow.
A series of snow showers began Sunday evening and are expected to run through Tuesday morning, with lake-effect showers also hitting the immediate Chicago area and parts of northwest Indiana.
However, relief could be just days away.
Highs in the 30s are once again in the forecast, signaling that the lengthy cold spell could soon be over.