Typhoon Sinlaku intensified to the equivalent of a major hurricane as it moved southeast of the Marianas on Saturday evening. At 11:00 p.m. EDT on Saturday the center of Typhoon Sinlaku was located at latitude 10.2°N and longitude 151.0°E which put the center about 505 miles (815 km) east-southeast of Guam. Sinlaku was moving toward the north-northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 944 mb.
Typhoon Watches are in effect for Guam, Rota, Tinian, and Saipan.
Typhoon Sinlaku continued to strengthen on Saturday evening as it moved toward the southern Marianas. A circular eye with a diameter of 20 miles (32 km) was as the center of Sinlaku’s circulation. The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the center of Typhoon Sinlaku. Storms near the center of Sinlaku generated upper level divergence that pumped mass away from the typhoon. The removal of mass caused the surface pressure to decrease.
The circulation around Typhoon Sinlaku was large. Winds to typhoon force extended out 60 miles (95 km) from the center of Sinlaku’s circulation. Winds to tropical storm force extended out 250 miles (400 km) from the center of Typhoon Sinlaku.
The Hurricane Intensity Index (HII) for Typhoon Sinlaku was 23.6. The Hurricane Size Index (HSI) was 21.2 and the Hurricane Wind Intensity Size Index (HWISI) was 44.8.
Typhoon Sinlaku will move through an environment favorable for intensification during the next 24 hours. Sinlaku will move over water where the Sea Surface Temperatures are near 29°C. It will move under the middle of an upper level ridge that is over the Western North Pacific Ocean. The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear. Typhoon Sinlaku will intensify during the next 24 hours. Sinlaku could intensify rapidly at times. Typhoon Sinlaku could strengthen to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale during the next 36 hours.
Typhoon Sinlaku will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Sinlaku toward the northwest during the next 24 hours. On its anticipated track, Typhoon Sinlaku will approach the southern Marianas in less than 48 hours.
Typhoon Sinlaku will be the equivalent of a major hurricane when it approaches the southern Marianas. Sinlaku will bring very strong winds and locally heavy rain to Guam, Rota, Tinian, and Saipan. Heavy rain is likely to cause flash floods in some locations.
Flood Watches are in effect for Guam, Rota, Tinian, and Saipan.
Typhoon Sinlaku could also cause a storm surge of up to 14 feet (4.3 meters) along parts of the coasts of the southern Marianas.