Boil the potatoes until slightly tender, 10-15 minutes.
While the potatoes are boiling, prepare the dressing.
Combine the greek yogurt, sour cream, buffalo sauce, dijon mustard and dill relish in a medium bowl. Add the salt, pepper and parsley, stir to combine.
Drain the potatoes and allow to cool.
Once the potatoes are cooled, chop them into cubes and add them to a large bowl with the celery and onions.
Add the dressing and toss to combine.
Place in the refrigerator for 30 minutes, then serve with your favorite main course.