Powerful Typhoon Muifa neared Ishigakijima on Sunday morning. At 5:00 a.m. EDT on Sunday the center of Typhoon Muifa was located at latitude 23.1°N and longitude 124.2°E which put it about 85 miles (135 km) south of Ishigaki, Japan. Muifa was moving toward the north-northwest at 5 m.p.h. (8 km/h). The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h). The minimum surface pressure was 942 mb.

Typhoon Muifa was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale as it approached Ishigakijima from the south of Sunday. morning. A small circular eye was present at the center of Muifa’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. The inner end of a rainband wrapped part of the way around the eye and eyewall. A second concentric eyewall may be in the process of developing. Other bands of showers and thunderstorms were revolving around the core of Typhoon Muifa’s circulation. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

Winds to typhoon force extended out 40 miles (65 km) from the center of Typhoon Muifa. Winds to tropical storm force extended out 140 miles (225 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Muifa was 25.1. The Hurricane Size Index (HSI) was 15.1 and the Hurricane Wind Intensity Size Index (HWISI) was 40.2. Typhoon Muifa was capable causing regional severe damage.

Typhoon Muifa will move through an environment favorable for intensification during the next 24 hours. Muifa 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. However, two factors could prevent Typhoon Muifa from intensifying even though it will be in a favorable environment. First, if concentric eyewalls develop, then Muifa could weaken when an eyewall replacement cycle occurs. Second, Typhoon Muifa will move slowly and its winds could mix cooler water up to the surface of the ocean. Typhoon Muifa could intensify a little more during the next 12 hours, but it is likely to slowly weaken after that time.

Typhoon Muifa will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Muifa slowly toward the north-northwest during the next 36 hours. On its anticipated track, the center of Typhoon Muifa could be over Ishigakijima within 24 hours. Muifa is likely to be the equivalent of a major hurricane when it approaches the southern Ryukyu Islands. The center of Typhoon Muifa could pass directly over Ishigakijima. Ishigakijima is already reporting heavy rain. The wind speeds will increase steadily as the center of Muifa approaches. Typhoon Muifa is capable of causing severe damage. Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 15W was spinning west-northwest of Wake Island. At 5:00 a.m. EDT on Sunday the center of Tropical Depression 15W was located at latitude 21.4°N and longitude 160.0°E which put it about 460 miles (745 km) west-northwest of Wake Island. The tropical depression was moving toward the east-northeast at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h). The minimum surface pressure was 1003 mb.