Even if you can't howl very well, I think the desired effect will be achieved. Now that I think about it, other wolflike things may work just as well. Being at the movie theater chewing on the seats, or in a library answering the call of nature. Make sure to do it in the romance section, though. Last thing I want is for someone to ruin the Dragonlance or Star Wars books.
Chances are, even lead bullets ought to do something to a smelly behemoth.
Enter the store and wait for the guy behind the counter to wake up. Now you've got the store to yourself. And don't worry about the video cameras, unless of course you're an unnaturally hairy guy. Or a bat, bear, tiger, etc. Thanks to Dungeons and Dragons, we have any number of furry things to choose from.