NAHA - A very strong Typhoon No. 18 is forecast to pass close to the Daito Islands before moving near Okinawa's main island and toward the Sakishima Islands, bringing violent winds, heavy rain and dangerous waves across a wide area of southwestern Japan. As of 9 p.m. on August 23, Typhoon No. 18 was moving west-northwest at 30 kilometers per hour over waters southwest of the Ogasawara Islands.
The storm had a central atmospheric pressure of 950 hectopascals and maximum sustained winds of 45 meters per second, maintaining a very strong intensity. Satellite images showed a large, well-defined cloud circulation and a clearly visible eye near the center.
The typhoon is expected to remain near its peak intensity through August 24, with maximum sustained winds of around 45 meters per second.
Although it is forecast to weaken slightly afterward, the storm is expected to remain strong on August 25, with maximum sustained winds of around 40 meters per second as it passes very close to the Daito Islands.
The Daito Islands are expected to experience the worst conditions mainly during the morning of August 25, when intense or extremely heavy rain and violent winds could strike the area.
Gusts of 40 to 50 meters per second are possible around Minamidaito Island and other parts of the Daito Islands as the strongest winds surrounding the typhoon move through.
Rain clouds associated with the storm could begin reaching the Daito Islands as early as the night of August 24, with particularly intense rainfall expected around the time of the typhoon's closest approach on August 25.
Typhoon No. 18 is then forecast to maintain strong intensity as it passes near Okinawa's main island through August 26 before turning somewhat southward and moving over waters north of the Sakishima Islands through August 27.
Active rain clouds are expected to spread over Okinawa's main island and Amami Oshima from the night of August 25, with rainfall likely to intensify as the storm approaches.
The precise areas receiving the heaviest rain could shift north or south depending on the typhoon's eventual track, making continued monitoring necessary.
Winds are also expected to strengthen across Okinawa's main island and the Amami region from the afternoon of August 25 through August 26, with gusts potentially exceeding 40 meters per second.
Areas on the right-hand side of the typhoon's direction of travel are particularly vulnerable to stronger winds because the storm's forward movement combines with its circulating winds.
The typhoon could also slow after passing near Okinawa, potentially prolonging severe winds across Okinawa and Amami. Winds are expected to strengthen later in the Sakishima Islands as well.
Dangerous waves will affect an increasingly wide area as Typhoon No. 18 approaches.
Okinawa, Amami and the Daito Islands face particularly rough seas, while swells generated by the storm are also expected to reach the Pacific coast from Kyushu through Shikoku and the Kinki region from August 25.
Waves of around 2 to 3 meters accompanied by swells are possible along parts of the Pacific coast, creating hazardous conditions even where the weather itself remains relatively calm.
Meanwhile, Typhoon No. 20 was moving southwest through the Taiwan Strait at about 10 kilometers per hour as of 9 p.m. on August 23.
The storm had a central pressure of 998 hectopascals and maximum sustained winds of 18 meters per second, making it relatively weak for a typhoon.
It is forecast to weaken further as it approaches mainland China and is expected to become a tropical depression by the night of August 24.
Despite weakening, Typhoon No. 20 continues to influence weather across the Sakishima Islands because large amounts of warm, humid air are flowing into the region on seasonal monsoon winds.
Active rain clouds have developed around Yonaguni Island and over waters south of Miyako Island, producing periods of locally heavy rain.
Rain has already continued across the Sakishima Islands since before Typhoon No. 20 formed. Over a 48-hour period, some areas of Miyako Island received around 300 millimeters of rain, while Ishigaki and Iriomote islands recorded more than 200 millimeters.
Further heavy rainfall could sharply increase the risk of landslides.
Active rain clouds are expected to affect Yonaguni Island in particular from before dawn through the daytime on August 24, while Ishigaki, Iriomote and Miyako islands could also experience periods of intense rain.
Because exceptionally humid air will remain over the region, rainfall could become heavier than forecast.
Short bursts of intense rain could cause flooded roads, inundation in low-lying areas and additional landslides, and authorities are urging residents to remain alert even as Typhoon No. 20 weakens and moves away.
Source: ウェザーニュース
