The North Bay’s newest Costco has its grand opening tomorrow. The more than 157-thousand-square-foot store in Napa is already attracting a crowd. About 15 people started camping out outside of it on Tuesday, wanting to be the first in line when the doors open. The Costco will feature a food court, bakery, pharmacy, optical department, hearing aid center, gas station and tire service center. The gas station opened last week. The new store will also boast the largest wine selection of any Costco in the country.