Begin by bringing a large pot of salted water to a rolling boil. Add the elbow macaroni and cook according to the package instructions until al dente, typically 8-10 minutes. Once cooked, drain the pasta in a colander and rinse under cold water to stop the cooking process. Set the macaroni aside to cool completely.

In a medium mixing bowl, whisk together the mayonnaise, sour cream, fresh lemon juice, Dijon mustard, fresh dill, onion powder, sea salt, and black pepper. Ensure the mixture is smooth and well-combined.

In a large mixing bowl, combine the cooled macaroni, diced red and green bell peppers, diced celery, and cooked shrimp. Gently toss the ingredients together to distribute them evenly.

Pour the creamy dressing over the pasta mixture. Using a spatula, carefully fold the dressing into the salad, making sure every piece is well-coated.

Cover the bowl with plastic wrap or transfer the salad to an airtight container. Refrigerate for at least 1 hour, but ideally overnight.

When ready to serve, give the salad a quick stir. If it appears a bit dry, add a splash of milk or a dollop of mayonnaise to restore its creamy consistency.