Impressive UFO over Houston, Texas

On August 22, 2015, a person was in Houston (Texas) and he took photo of night sky. Later, he noticed several white orbs in formation on pictures above the downtown of the city. What is it?

Witness statement:

I was taking pictures of the clouds because they appeared to be in a spiral/ almost portal shape in the was after observation of these pics that the UFO was seen. In the pictures you can see the object was headed north. I was very excited.