Last night we noticed Stormy having difficulty walking. Our thoughts immediately went to Zoey when she did this over Labor Weekend in 2009 and ended at the emergency vet clinic for the entire weekend. If Stormy is experiencing the same thing, it means her kidneys are beginning to fail which is common in cats as they age.
Originally the plan was to take her into the veterinarian on Saturday, but at 2:00 this morning I couldn't sleep, got up and discovered she was struggling ever more with her hindquarters. So, we will be taking her in this morning. Updates as they become available.