Make sure all the meat has been removed from the carcass. Set aside.
In a large kettle or stockpot combine the carcass, the celery, the carrots, the garlic, the onions, the peppercorns, and enough water to cover the mixture by 2 inches (about 6 quarts) and simmer the mixture, uncovered, for 3 hours. Strain the stock through a large sieve into a large bowl, leaving the solids in the sieve, return the stock to the kettle, and boil it until it is reduced to about 10 cups.
When the solids in the sieve are cool enough to handle, remove any turkey meat from the carcass and add it to the stock with carrots, crushed lightly, discarding the remaining solids. Add the tomatoes and bring the soup to a boil. Stir in the noodles, boil the soup, stirring occasionally, for 8 to 10 minutes, or until the noodles are tender, and stir in the parsley and salt and ground black pepper to taste. The soup may be made in advance, cooled completely, uncovered, and kept covered and chilled for 2 days or covered and frozen for 2 months.