Looks like Jay Leno is going out on top. In his final May as host of The Tonight Show, Leno is No. 1 on the late-night heap for the first full week of the sweep and drawing some of his best ratings in months. That’s a success story that could prove awkward for NBC at next week’s upfront presentation as it sets the stage for Jimmy Fallon to take over The Tonight Show next year. It’s a situation made all the more uncomfortable because NBC has been boasting about Leno’s results, and the struggling network’s only other heavyweights right now besides Leno are The Voice and Sunday Night Football. Then there’s the fact that Fallon is in a far tighter race in his current 12:35 AM time slot than Leno is at 11:35 PM. With 3.4 million viewers on average for the week of April 29-May 3, The Tonight Show easily bested CBS’ The Late Show With David Letterman (2.8 million viewers) and ABC’s Jimmy Kimmel Live! (2.5 million viewers). ABC ran a Kimmel encore show on May 3 as it usually does on Fridays. Over the frame, Leno matched his ratings result of the comparable week last year with a 0.8/3 among adults 18-49. That translated into 1.039 million viewers in the demo last week compared with Letterman’s 0.6/3 (766,000 viewers) and Kimmel’s 0.6/3 (820,000).