This map from wundergound shows the current jet stream patter. As you can see the trough of the jet stream is mostly in Canada. Also the wind patterns for the south show the hot dry air blowing up towards us. These two wind patterns mostly explain why the temperature rose over the last few days. With the winds blowing from the south, this churns up the continental tropical air, which is hot and dry, and brings it up to the north. With the jet stream trough not in the middle of the country like it has been previous, the air can flow up unhindered to the top of the United States.


This map further illustrates the impact of the jet stream on temperature. On the south side of the trough the temperature is 50s and 60s, while on the north side it is below 40.