Moving NorthTOKYO, Aug. 14 (SS)—Okinawa was alerted today to brace for Typhoon Grace which is approaching the island bastion while Tokyo Weather Central reported another typhoon, Helen, advancing tpwardJapan 650 miles southeast of Tokyo.Grace was 150 miles southeast of' Okinawa this morning.Maximum winds of 115 miles an hour at its center were reported.At 7 a.m. (1ST) winds of 35 miles an hour were reported over Okinawa. They were expected to increase to 80 miles an hour tonight when Grace passes 60 miles south of the island.Typhoon Helen, the fourth of the 1954 season, was traveling north at five miles an hour, with maximum winds ofSS MapGrace (Black), Helen (White)80 miles an hour.Tokyo Weather Central said Helen was expected to be 550 miles southeast of tomorrow morning.Air Force planes of thekota-based 56th Weather con. Sq. are keeping bothTokyo byYo-Re-’ty-phoons under constant watch