ThunderCloud Subs, approaching 40 years in operation, opened its 30th store this week, bringing the Austin-based sandwich chain to the expanding Southwest Parkway area. The 1,300-square-foot store is located at 12400 West Highway 71 in the HEB Grocery Co. shopping center. The store plans to hire a total of 15 workers. It will seat roughly 60 people, including patio space for 15 customers. ThunderCloud Subs also said Tuesday that its 31st store is planned for San Marcos and will open in late spring…