A Siberian forest doesn't exactly sound like a vacation destination -- unless you're into trying to spot big cats. Scrub your travel plans and let biologist Chris Morgan do the hard work in "Siberian Tiger Quest" (7 p.m., KTCA, Ch. 2), a documentary that kicks off a new season of "Nature."Bay watch
When Al Roker isn't finding out what's going on in your neck of the woods in the morning, he's developing a reality series about unsung heroes fighting the elements. The latest: "Coast Guard Florida" (8 p.m., Weather), a look at the men and women trying to keep ports and waterways safe on the southeast border.Lopsided battle
One of the season's more promising new shows is going up against one of the more disappointing ones. The show to watch: "Nashville" (9 p.m., KSTP, Ch. 5), a sudsy affair with Connie Britton as an aging country-music star trying to work her way back up the charts. The clunker: "Chicago Fire" (9 p.m., KARE, Ch. 11), a Dick Wolf project that could have been an intriguing twist on the "Law & Order" formula. Instead, it's almost all about hunky heroics that go over the top.