In a large dutch oven, melt butter over medium high heat. Add onion and celery and season with a pinch of salt. Saute for about 2 minutes, then stir in the flour and cook for one minute.Pour in the broth, half and half, potatoes, sage, thyme, and pepper. Bring to a boil, then reduce heat to medium and cover. Simmer for about 10 minutes. Add the carrots and simmer for 7 minutes or until the carrots are tender. Stir in the turkey and remove from heat. Add parsley and season with salt and pepper to taste.