Costco will give you your money back.

You’re over East, like me … cept several hundred miles North; I’m on the Blue Ridge in Virginia..  Searching online, my guess would be ‘Cherry Blossom Wilt.’  Here’s some of what I found: 

“Blossom wilt is a fungal disease of apples, pears, plums, cherries and related ornamental trees. It kills blossoms, spurs and small branches.”

“You may see the following symptoms: Brown and shriveled blossoms and leaves on the fruiting spurs at flowering time. Small, buff-colored pustules of the causal fungi on dead tissues. Usually seen under wet conditions.”

-- Online photos look similar to your cherry tree’s condition.  If you were in Ontario Oregon … maybe not..  But over East, it seems to be a good year for fungus & bacteria   If you’ve not yanked it, you can search further for possibilities and recommendations..