The city will enforce mandatory parking bans in several neighborhoods Friday and Saturday as crews work to clear streets following this week’s heavy snowfall, with frigid temperatures and another storm on the way. The National Weather Service has issued a cold weather advisory for Newport and much of southern New England from 7 p.m. Thursday to 11 a.m. Friday. Residents in the Lower Thames and Spring Street corridor must move vehicles to off-street parking Friday from 7 a.m. to 4 p.m. A second parking ban takes effect Saturday from 7 a.m. to 4 p.m. in the Kerry Hill neighborhood and on Second and Third streets in The Point. That ban covers more than 40 streets, including Farewell Street, Dr. Marcus Wheatland Boulevard and Marlborough Street from Farewell to Broadway.