Line. On December 2, based on satellite estimates, the CPHC upgraded the depression to Tropical Storm Paka while located about 1000 km (625 mi) south-southeast of Johnston Atoll. Due to the presence of high clouds across the area, forecasters had difficulty at times in locating the low-level circulation. After becoming a tropical storm, Paka remained nearly stationary for about two days before resuming a slow motion to the west-southwest. It steadily intensified due to warm water temperatures, and on December 3 the storm attained winds of 105 km/h (65 mph). The next day, however, it encountered dry air and began weakening; by December 6, the winds had decreased to minimal tropical storm status for about 12 hours. Subsequently, Paka began to re-intensify, and on December 7 the storm crossed the International Date Line into the western North Pacific Ocean with winds of 80 km/h (50 mph). Upon entering the western North Pacific Ocean, tropical cyclone warning duties transferred from the CPHC to the Japan Meteorological Agency (JMA), and the JMA first assessed Paka as a 65 km/h (40 mph) storm. The Joint Typhoon Warning Center (JTWC) unofficially assumed warning duties for interests in the United States Department of Defense. Paka continued to intensify after crossing the date line, and from late on December 7 through early the following day it remained a strong tropical storm. However, upper-level wind shear increased, and it again weakened. At 1200 UTC on December 9, the JTWC assessed Paka as an 85 km/h (50 mph) tropical storm and forecast it to continue weakening. By December 10, the shear had begun to decrease as the storm moved through the Marshall Islands, and that night the JTWC upgraded Paka to typhoon status. Paka officially attained typhoon status when JMA classified it with winds of 120 km/h (75 mph) at 0000 UTC on December 11. After attaining typhoon status, Paka strengthened fairly quickly, and by December 12 it reached sustained winds of 150 km/h (90 mph) for a ten-minute (10 min) duration, or 215 km/h (135 mph) over a one-minute (1 min) duration. Subsequently, it briefly weakened as its forward motion increased. However, Paka again re-intensified, and at 1200 UTC on December 14 it attained the unofficial ranking of Category 5 super typhoon status while over the open Pacific Ocean with estimated 1-minute sustained winds of 260 km/h (160 mph). At the same time, the JMA classified it