The threat posed by Typhoon Sinlaku caused a Typhoon Watch to be issued for Guam, Rota, Tinian, and Saipan on Saturday. At 11:00 a.m. EDT on Saturday the center of Typhoon Sinlaku was located at latitude 9.2°N and longitude 150.9°E which put the center about 535 miles (865 km) southeast of Guam. Sinlaku was moving toward the northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h). The minimum surface pressure was 965 mb.
Typhoon Watches are in effect for Guam, Rota, Tinian, and Saipan.
Typhoon Sinlaku continued to strengthen on Saturday as it moved toward the southern Marianas. A small circular eye 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 size of the circulation around Typhoon Sinlaku continued to increase on Saturday. Winds to typhoon force extended out 50 miles (80 km) from the center of Sinlaku’s circulation. Winds to tropical storm force extended out 250 miles (400 km) in the northeastern quadrant of Typhoon Sinlaku. Winds to tropical storm force extended out 165 miles (265 km) in the other quadrants of Sinlaku’s circulation.
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 30°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 is likely to strengthen to the equivalent of a major hurricane during the weekend.
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 move toward the southern Marianas. Sinlaku will approach Guam in 48 hours.
Typhoon Sinlaku will be the equivalent of a major hurricane when it approaches the southern Marianas. Sinlaku could 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. Typhoon Sinlaku could cause a storm surge of up to 13 feet (4 meters) along parts of the coasts of the southern Marianas.