Place potatoes in a large pot and cover with water. Bring to a boil and cook until potatoes are tender, about 10-15 minutes. Drain and let cool slightly.
In a large bowl, combine sour cream, mayonnaise, Dijon mustard, white vinegar, garlic powder, salt, and pepper.
Add the slightly cooled potatoes to the dressing. Add chopped celery, pickles, red onion, parsley, and fresh dill. Gently mix until the potatoes are well coated with the dressing.
Refrigerate the salad for at least 1 hour to allow flavors to meld. Serve chilled.