Will showcase first-party titles arriving this summer
Nintendo has been promising a string of Nintendo Directs through the end of E3 week, and the first one will be arriving tomorrow, May 17, at 7:00 AM PST / 10:00 AM EST / 4:00 PM CEST. It will be available on the usual Nintendo Direct page.
President Satoru Iwata will once again be appearing on screen to discuss Nintendo's upcoming lineup, which will cover first-party Wii U and 3DS games arriving this summer. I expect we should be hearing more news about Pikmin 3, potential unannounced titles, and hopefully a release date for The Wonderful 101.
There will be an additional Nintendo Direct just before the start of E3 in June, covering titles for the fall and beyond.