Typhoon Rai rapidly intensified to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Wednesday night. At 10:00 p.m. EST on Wednesday the center of Typhoon Rai was located at latitude 9.8°N and longitude 126.3°E which put it about 90 miles (145 km) east of Dinagat, Philippines. Rai was moving toward the west at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h). The minimum surface pressure was 915 mb.

Typhoon Rai continued to intensify very rapidly during Wednesday evening and it strengthened to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale. A small circular eye with a diameter of 8 miles (13 km) was at the center of Rai’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Rai. Storms near the core of Rai generated strong upper level divergence that pumped large quantities of mass away to the west and north of the typhoon. The continued rapid removal of mass allowed the surface pressure to decrease very rapidly.

The circulation around Typhoon Rai exhibited more symmetry as it rapidly intensified. Winds to typhoon force extended out 50 miles (80 km) from the center of Rai. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Rai was 35.0. The Hurricane Size Index (HSI) was 17.5 and the Hurricane Wind Intensity Size Index (HWISI) was 52.5. Typhoon Rai was capable of doing regional catastrophic damage.

Typhoon Rai will move through an environment favorable for intensification during the next few hours. Rai will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the southern side of an upper level ridge over the Western North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Typhoon Rai’s circulation. Those winds will cause some vertical wind shear but the wind shear will be too small to prevent intensification. Typhoon Rai could continue to strengthen until the center makes landfall in southern Philippines in a few hours. Rai will weaken when the center passes over land.

Typhoon Rai will move south of a surface high pressure system over the Western North Pacific Ocean. The high pressure system will steer Rai toward the west-northwest during the next 36 hours. On its anticipated track the center of Typhoon Rai will pass over Siargao Island in a few hours. The core of Rai will pass over Dinagat Island, southern Leyte, northern Bohol, Cebu, northern Negros and southern Panay Island. Typhoon Rai will weaken when the center passes over land, but it will be the equivalent of a major hurricane when it moves across the southern Philippines. Typhoon Rai will bring very strong winds and locally heavy rain to northern Mindanao, Siargao Island, Dinagat Island, Samar, Leyte, Cebu, Negros, Bohol and Panay Island. Heavy rain could cause flash floods in some locations. Rai will cause a significant storm surge along coasts where the wind blows the water toward the shore. Typhoon Rai could cause catastrophic damage in locations that experience the inner core of the circulation.