TOKYO - As of 3 a.m. on November 6, Typhoon No. 31 (In-fa) was moving northeast across the Pacific Ocean east of Japan at 75 kilometers per hour and was expected to become an extratropical cyclone by Friday afternoon, although dangerous swells and high waves could continue along Japan's Pacific coast throughout the day.
According to the Japan Meteorological Agency, the storm was centered near 33.9 degrees north latitude and 147.8 degrees east longitude, with a central atmospheric pressure of 985 hectopascals. Maximum sustained winds near its center reached 25 meters per second, equivalent to 90 kilometers per hour, while gusts reached 35 meters per second, or 126 kilometers per hour.
The storm's area of strong winds, defined as sustained speeds of at least 15 meters per second, extended approximately 390 kilometers southeast of its center and 220 kilometers northwest. It no longer had a designated storm-force wind zone, indicating that its intensity had weakened considerably from earlier in the week.
In-fa was forecast to accelerate further as it traveled northeast, reaching speeds of approximately 100 kilometers per hour by 3 p.m. on November 6 as it moved into waters far east of Japan and away from Hokkaido. The latest available forecast indicated that it would undergo a transition into an extratropical cyclone during the afternoon, with its central pressure expected to remain near 984 hectopascals.
Although the storm was moving rapidly away from Japan, weather authorities continued to warn of lingering rough seas along the Pacific coast. Large swells generated during the typhoon's approach could persist well after its strongest winds had departed, creating hazardous conditions for fishing vessels, coastal shipping and people approaching exposed shorelines.
The Ogasawara Islands, including Chichijima and Hahajima, experienced the greatest threat from the storm as it passed through surrounding waters on November 5. Earlier forecasts had warned of wind gusts exceeding 20 meters per second and waves reaching approximately five meters, accompanied by powerful swells. Conditions around the islands were expected to improve gradually on Friday as the typhoon moved farther northeast.
In-fa had previously been classified as a strong typhoon, with a central pressure of 970 hectopascals, sustained winds of 35 meters per second and maximum gusts of 50 meters per second as of 3 p.m. on November 4. Its subsequent weakening coincided with a marked increase in forward speed as it turned northeast, away from the Japanese archipelago.
The storm also influenced weather across eastern Japan earlier in the week. Moist air circulating around the typhoon contributed to the development of rain clouds along a frontal system extending across waters south of Honshu, raising concerns about heavy rainfall in parts of the Kanto and Tokai regions and the Izu Islands.
The typhoon's transition into an extratropical cyclone does not necessarily mean that its winds and waves will immediately disappear. Such systems can retain strong winds over extensive areas as their energy source shifts from warm tropical waters to temperature contrasts in the atmosphere.
By early November 7, the former typhoon was expected to be moving northeast across waters east of the Kuril Islands, leaving the Japanese mainland increasingly distant from the storm's direct influence.
Weather authorities advised residents and maritime operators along the Pacific coast to remain cautious of high waves and long-period swells through November 6, even as the overall threat to Japan continued to diminish.
Source: ウェザーニュース
