You probably know the weather will be cool over the next week, us meteorologists tell you all the time what will be happening. This post is about why it's happening.
The jet-stream is a narrow band of really fast winds in the troposphere, about 10km above the earth but can vary between 4-8 miles. The speeds can top out well over 200mph but tend to average around 110mph. In the northern hemisphere it flows from west to east and it sets up between warm air coming from the tropics and the cold air coming from the north pole. The rotation of the earth helps to move the air (that's why we feel wind) and the jet stream.
Think of the jet stream, like a river, when you're in it, you go where it goes. It's the same with weather patterns, when the jet stream is south of us, warm air doesn't move northward, we end up trapped under cooler air. It can be known as a positive arctic oscillation when the jet-stream is strong and not much "waviness" occurs, cold stays north and warm stays south.
The polar-jet which affects our weather, typically doesn't rise to near the US/Canadian boarder until the summer. We get warm surges when a "buckle" in the jet stream occurs, take for instance the really warm start to the month of April. The jet stream was north of WNY and allowed warmer air from the south to settle in! During that time the arctic oscillation was negative.
For the next week, at least, the polar jet will remain below of WNY, and have a few waves in it keeping our weather cool.
By next week it'll be 15 degrees below average.