Not very convincing IMHO. The aforementioned General was really ambiguous about where this chunk of metal could hit. There's little question that it's orbit will decay, but let me throw this out there for you to marinate on: What if the whole deal is a setup?
Hear me out... what if they are just priming us for a major catastrophe, such as Manhatten getting hit... No wait, bad example- that would be a blessing! Ok, something like Fenway Park getting hit?
I think they already have the trajectory and maybe even the exact moment this thing is coming down mapped out. Wouldn't suprise me a bit. Just pray that it hits New York...

Sorry... Die Hard Red Sox fan. let's say the Bronx then, youse guys have enough to fret over what with that Cloverfield monster and all.
I seriously think, though, that it will hit a populated area, though not as dense as a "major" city. Think Youngstown, Ohio, or Erie, Pa. Enough to "skin our knee" and keep the proles in line.