Discontinuous. Whenever a nonconforming use, in or on the land or within a building or structure or portion thereof, has been discontinued for a continuous period of more than one year, such discontinuance shall be deemed to be an abandonment of such nonconforming use, and any subsequent use thereof shall conform to the applicable provisions of the zoning district in which such use is located, and the prior nonconforming use shall not thereafter be resumed unless a variance is granted by the Zoning Hearing Board in accordance with § 310-19A of Article IV.