Your best bet is to contact your local agricultural extension service. They will be able to understand the conditions in your area better than anyone and will be glad to help. That being said, you might try:
Amur Maple grows to 20 feet tall and produces good fall color
Crape Myrtle grows to 25 feet and produces late summer flowers. The blooms come in many colors including some brilliant reds. The leaves are colorful in fall.
Smoke Tree grows to 15 feet with great puffs of soft pink color in summer. The leaves are good for fall color as well.
Redbud is a native that grows between 15 and 30 feet tall depending on the cultivar. It produces beautiful flowers in spring.
Research any suggestions before you buy a tree. Various cultivars grow to different heights, produce a variety of bloom colors, or offer a variety of fall colors.