Trader Joe’s stores won’t be open on Thanksgiving Day 2013 (Thursday November 28). The Thanksgiving Day closing is noted on the Trader Joe’s homepage (see above).
Trader Joe’s will be open normal hours the days before Thanksgiving, so you could stop in early for Trader Joe’s Thanksgiving specials. Find Trader Joe’s regular opening hours here.
Although Trader Joe’s (and Aldi and Costco also) will be closed on Thanksgiving, many other grocery stores and restaurants will be open for Thanksgiving Day needs.