Creamy Summer Potato Salad

Ingredients

• 1/2 cup mayonnaise
• 1/4 cup plain low-fat yogurt
• 2 tablespoons prepared mustard
• 1/4 cup low-fat sour cream
• 1 1/2 tablespoon white wine vinegar
• 1/4 cup chopped green onion
• 1/4 cup celery, chopped
• 1 tablespoon sugar
• 1/2 teaspoon salt
• 1/2 teaspoon celery seed
• 1/4 teaspoon white pepper
• 1/8 teaspoon garlic powder
• 6 medium round red potatoes