Initially, forecasters anticipated Babe to maintain its westward course as it strengthened and threaten the Philippines; however, its forward motion gradually slowed as it neared the region. On September 5, an upper-level trough formed over northeastern Asia and created a weakness in the subtropical ridge, allowing Babe to turn north-northwestward. Over the following two days, the storm quickly strengthened as divergence increased ahead of the storm, with Babe attaining typhoon status early on September 6 Between 0832 UTC on September 5 and 2204 UTC on September 7, the storm's barometric pressure dropped from 988 mbar (hPa; 29.18 inHg) to 907 mbar (hPa; 26.79 inHg), approximately 1.3 mbar (hPa; 0.04 inHg) per hour. Early on September 8, Babe attained its peak intensity with winds of 240 km/h (150 mph) while situated approximately 465 km (290 mi) southeast of Ishigaki Island. This ranked it as the first and only super typhoon of the 1977 season. At this time, the Japan Meteorological Agency estimated the storm to have had peak ten-minute sustained winds of 205 km/h (125 mph) and a minimum pressure of 905 mbar (hPa; 26.72 inHg).