Typhoon Bolaven rapidly intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Tuesday evening. At 11:00 p.m. EDT on Tuesday the center of Typhoon Bolaven was located at latitude 17.5°N and longitude 143.8°E which put it about 245 miles (390 km) north-northwest of Guam. Bolaven was moving toward the north-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 185 m.p.h. (295 km/h). The minimum surface pressure was 920 mb.

Typhoon Warnings were in effect for Rota, Tinian and Saipan. Tropical Storm Warnings were in effect for Agrihan, Pagan and Alamagan.

Typhoon Bolaven rapidly intensified to the equivalent of a Category 5 hurricane west of the Marianas on Tuesday evening. A small circular eye with a diameter of 14 miles (22 km) was at the center of Bolaven’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 core of Typhoon Bolaven. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Bolaven was very symmetrical. Winds to typhoon force extended out 25 miles (40 km) from the center of Bolaven’s circulation. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Bolaven was 35.0. The Hurricane Size Index (HSI) was 11.5 and the Hurricane Wind Intensity Size Index (HWISI) was 46.5.

Typhoon Bolaven will move through an environment favorable for intensification during the next 24 hours. Bolaven will move over water where the Sea Surface Temperatures are near 30°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Typhoon Bolaven could continue to intensify during the next 24 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could form. If concentric eyewalls form, then an eyewall replacement cycle could cause Typhoon Bolaven to weaken.

Typhoon Bolaven will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Bolaven toward the north-northwest during the next 24 hours. On its anticipated track, the Typhoon Bolaven will stay west of the Marianas during the next 24 hours.