This is the Printed Jessie Blouse (item #12576) from the J.Crew Outlet. I believe this top was out last summer from retail, and I see it pop up from time to time in the sale section on J.Crew's website. This blouse is numerically sized, and retailed for $54.50. It was available in several different patterns.
I left this shirt behind, as I'd already picked one up in a different yellow pattern that I prefer to this pattern. I also like this pattern, but didn't love this shirt enough to get it in two different patterns.