Typhoon Opal, known in the Philippines as Super Typhoon Naning, was an intense Category 5-equivalent typhoon in the extremely active 1964 Pacific typhoon season. Opal also had the largest wind circulation of any typhoon in 1964, with a total span of .Data from the Joint Typhoon Warning Center (JTWC) indicated that Opal's winds, along with Sally earlier in the year, were the highest of any typhoon in 1964. As the thirty-ninth named storm and the twenty-sixth typhoon of the season, it originated from a tropical wave in early December, with its wind circulation developing by December 8. This system quickly organized, gaining the name Opal, and reaching typhoon status on December 9. Opal moved through Yap and Palau for two days. On that last day, Opal reached its peak intensity with one-minute sustained winds of and a central pressure of 895 hPa (26.43 inHg). On December 14, Opal passed north of some Filipino islands and its winds began to lose intensity. Later that day, Opal made landfall in the Philippines with one-minute sustained winds of . Opal weakened further as it moved over Luzon. Its center then executed a small counterclockwise loop over western Luzon before curving north and briefly emerging into the Lingayen Gulf as a tropical storm. Opal crossed northwestern Luzon and the Babuyan Islands on December 16 and later became extratropical near Okinawa on December 17; this phase of Opal's development dissipated the next day. Meteorological history Opal formed from a tropical wave moving through the Caroline Islands in early December, with an initial wind circulation developing by December 8. The newly formed system organized quickly; by the time a reconnaissance aircraft encountered the system southwest of Chuuk Lagoon on December 9, Opal was already a typhoon with an eye spanning across. Between December 10–12, Opal moved between Yap and Palau, passing north of Kayangel with one-minute sustained winds of . On December 12, Opal reached its peak intensity with one-minute sustained winds of and a central pressure of 895 hPa (26.43 inHg). On December 14, Opal passed north of Catanduanes and Polillo Island and its winds began to lessen. Later that day, Opal made landfall on central Luzon with one-minute sustained winds of . The typhoon weakened further as it moved over Luzon. Its center then executed a small counterclockwise loop over western Luzon before curving north and briefly emerging into the Lingayen Gulf as a