Bring a large pot of salted water to a boil and cook the rotini pasta according to package instructions until al dente.
Drain the pasta and rinse it under cold water until completely cooled to stop the cooking process and prevent sticking.
Transfer the cooled pasta to a large mixing bowl.
Add the sliced dill pickles, diced celery, red onion, and fresh dill to the bowl with the pasta.
In a separate bowl, whisk together mayonnaise, sour cream, pickle juice, Dijon mustard, garlic powder, dried dill, salt, and black pepper until smooth and creamy.
Pour the creamy dill dressing over the pasta mixture and toss gently until everything is evenly coated.
Cover and refrigerate the pasta salad for at least 30 minutes before serving so the flavors can blend together.
Toss again before serving and garnish with extra pickle slices or fresh dill if desired.