UPDATE 1-U.S. natgas futures seesaw early, milder weather seen next week

* Milder temperatures expected for eastern United States * Nuclear plant outages edge back below normal * Coming Up: Baker Hughes drilling rig data later Friday By Eileen Houlihan NEW YORK, Sept 13 (Reuters) - U.S. natural gas futures seesawed on either side of unchanged early on Friday, with most traders expecting forecasts for milder weather next week and late this month in consuming regions in the Northeast and Midwest to weigh on prices. In addition, nuclear power plant