In a large kettle, combine water, ribs, soup bones, tomatoes, celery, onion, 1/4 cup parsley, salt and pepper. Cover and simmer for 2 hours. Add carrots and parsnips; cover and simmer for 1 hour or until meat and vegetables are tender.
With a slotted spoon, remove meat, bones and vegetables. Strain broth and skim off fat; return all but 1 cup broth to kettle. Set reserved broth aside. Remove meat from the bones; dice and return to kettle. Discard celery and onion. Cut parsnips, carrots and tomatoes into 1/2-in. pieces and return to kettle. Add remaining parsley.
In a large bowl, combine the sour cream, flour, nutmeg if desired and reserved broth; stir into soup. Add noodles. Cook and stir until thickened and heated through (do not boil).