Trees, Shrubs and Conifers: Ornamental Cherry Tree identification, please, 1 by xrdh

xrdh wrote:
I have two ornamental cherry trees that I bought at Wal-Mart several years ago. One blooms white and one blooms pink. The white blooming tree is larger and is thriving much better than the pink variety, so I would like to purchase another white one just like it. Unfortunately, I have forgotten what variety of ornamental cherry tree it is.

Attached are photos taken today (August 29th, Zone 5) and one photo of it blooming in May (far left tree).

Please help.