Here's a general articles on nosebleeds in cats....
http://www.pets.ca/cats/articles/nosebleeds-and-cats/
I Guess it's possible it's due to dry air..hmmmm
I'd likely keep an eye on it for 24 hours but I would also call my vet to see if the cat needs to be brought in immediately. If it's a 1 time thing, it's different than if it's a continuing thing.
My cats are indoor cats so they rarely get into trouble, but if your cat is an outdoor cat....lots of additional reasons this may have happened.
Good luck!
