Tag Archives: Ryukyu Islands

Large Dangerous Typhoon Dujuan Nearing Taiwan

Large and dangerous Typhoon Dujuan is nearing Taiwan.  At 11:00 p.m. EDT on Sunday the center of Typhoon Dujuan was located at latitude 23.5°N and longitude 123.2°W which put it about 185 miles (300 km) southeast of Taipei, Taiwan.  Dujuan was moving toward the west-northwest at 13 m.p.h. (21 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 170 m.p.h. (275 km/h).  The minimum surface pressure was 912 mb.

Typhoon Dujuan is a very symmetrical storm with a large eye.  Winds to hurricane force extend out 60 miles from the center.  A weather station on Ishigaki Jima, Japan has reported winds over 54 m.p.h. (87 km/h) for the past five hours even though the center is passing south of that island.  The upper level winds around the typhoon are light and upper level divergence is pumping out mass in all directions  Typhoon Dujuan is likely to maintain its intensify until it makes landfall in Taiwan.  When the core of the typhoon moves over the mountains on Taiwan it will weaken.  However, given Dujuan’s size and intensity, it is likely to still be a typhoon when it moves west of Taiwan.

A subtropical ridge north of Dujuan is steering the typhoon toward the west-northwest and that general steering pattern is expected to continue.  On its anticipated track Dujuan will make landfall in northeastern Taiwan in less than 12 hours.  It will move across Taiwan and the center could reform northwest of that island.  Dujuan could make a landfall in China between Xiamen and Fuzhou in less than 24 hours.

Dujuan has the potential to be a very destructive typhoon.  It has a Hurricane Intensity Index of 29.9 and a Hurricane Size Index of 21.3.  Those numbers produce a Hurricane Wind Intensity Size Index of 51.2.  Those Indices suggest it is capable of producing widespread significant damage.  In addition to wind damage, Dujuan is capable of producing very heavy rainfall and floods.

Powerful Typhoon Dujuan Heads Toward Taiwan

Powerful Typhoon Dujuan turned west on Saturday and headed for Taiwan.  At 11:00 p.m. EDT on Saturday the center of Typhoon Dujuan was located at latitude 22.3°N and longitude 127.0°E which put it about 380 miles (610 km) east-southeast of Taipei, Taiwan and about 300 miles (480 km) south of Okinawa.  Dujuan was moving toward the west at 9 m.p.h. (15 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 925 mb.

Dujuan continued to intensify on Saturday and it is a powerful well organized typhoon.  Dujuan has a large symmetrical eye which is surrounded by strong thunderstorms.  Upper level divergence is pumping out mass and the surface pressure is decreasing.  Dujuan is over warm Sea Surface Temperatures and there is not much vertical wind shear.  Further intensification is possible, although if concentric eyewalls form, it could disrupt the intensification trend.

An upper level ridge north of Dujuan steered the typhoon a little north of due west on Saturday.  That general motion is expected to continue for another day or two.  On its anticipated track Dujuan will pass near the southwestern Ryukyu Islands in about 24 hours.  It will approach Taiwan in about 30 hours and it could reach China in less than two days.  Dujuan is a large powerful typhoon and it will bring strong winds and heavy rain.  It could produce flooding in parts of Taiwan and eastern China.

Dujuan Reaches Typhoon Intensity South of Okinawa

Tropical Storm Dujuan continued to strengthen on Thursday and it reached typhoon intensity.  At 11:00 p.m. EDT on Thursday the center of Typhoon Dujuan was located at latitude 19.4°N and longitude 132.1°E which put it about 575 miles (930 km) south-southeast of Okinawa.  Dujuan was moving toward the north-northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 980 mb.

The circulation around Typhoon Dujuan is becoming increasingly well organized.  A spiral band wrapped entirely around the center of circulation creating a large eye in the middle of the typhoon.  Additional spiral bands are forming, especially in the southern half of the circulation.  Thunderstorms in the eyewall are generating upper level divergence which is increasing with time.  Recent satellite images suggest that they eye may be contracting which would be another sign of intensification.

Dujuan is in an environment that favors intensification.  The Sea Surface Temperatures are warm and the speed of the upper level winds is decreasing.  An upper level ridge west of Dujuan is producing some northerly winds over the top of the typhoon, but the vertical wind shear is decreasing.  Intensification is likely and a period of rapid intensification is possible.  Dujuan could become the equivalent of a major hurricane in 24 to 48 hours.

Typhoon Dujuan is between a subtropical ridge to its northeast and another ridge to its northwest.  As a result, it moved slowly toward the northwest on Thursday.  Dujuan is expected to continue to move in a general northwesterly direction for another day or two.  The ridge west of Dujuan is expected to extend north of the typhoon during the weekend.  When the ridge extends north of Dujuan, it will steer the typhoon more toward the west.

On its anticipated track Typhoon Dujuan could approach the southwestern Ryukyu Islands including Ishigaki JIma in 60 to 72 hours.  Dujuan could be near Taiwan in about three and a half days and it could reach the coast of China in less than five days.  Dujuan could be a large and powerful typhoon capable of bringing strong winds and heavy rain by the time it reaches those areas.