It's not all that unusual to see large temperature changes driven by strong cold fronts this time of year. Even though it is technically still summer, the sun isn't as strong as it was in early August. The early pushes of cooler air are becoming stronger and larger in extent. The polar jet stream is starting to become a more dominating force driving mid latitude systems the US and Canada much faster and with more punch. The front forecast to push through the Great Lakes late Wednesday/early Thursday is a prime example.
HUGE temperature contrast along the front.
The cool push of air is very strong and will envelop the northern 2/3rds of the US.