Tag Archives: Okinawa

Typhoon Namtheun Heads for Southern Japan

Typhoon Namtheun spun up quickly on Thursday and moved steadily toward Kyushu in southern Japan.  At 11:00 p.m. EDT on Thursday the center of Typhoon Namtheun was located at latitude 26.6°N and longitude 130.8°E which put it about 335 miles (540 km) south of Kagoshima, Japan.  Namtheun was moving toward the north at 7 m.p.h. (11 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 975 mb.

Typhoon Namtheun developed quickly from a low pressure system along a surface trough.  Namtheun has a small but very well organized circulation.  It has a tiny pinhole eye surrounded by a ring of strong thunderstorms.  Several other rainbands are spiraling around the ring of strong thunderstorms.  The thunderstorms are generating upper level divergence which is pumping out mass in all directions.  The upper level divergence is slightly less to the west of the center of circulation.

Typhoon Namtheun is in an environment favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  Although there is a large upper level trough over eastern Asia which contains strong southwesterly winds, Typhoon Namtheun developed east of those strong winds.  It is in an area where the upper level winds are weaker and there is little vertical wind shear.  Namtheun is likely to intensify more during the next day or two.  However, Namtheun’s small circulation means that it will respond very rapidly to positive or negative changes in its surrounding environment.

A ridge to the east of Namtheun is steering the typhoon toward the north and that general motion is expected to continue for several more days.  On its anticipated track Typhoon Namtheun could be very near the southern tip of Kyushu within 48 hours.  It could bring strong winds and heavy rain to parts of southern Japan.

Typhoon Lionrock Turns in the Direction of Japan

After meandering southeast of Okinawa for several days Typhoon Lionrock started moving northeast toward Japan on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Lionrock was located at latitude 23.7°N and longitude 133.0°E which put it about 920 miles (1485 km) south-southwest of Tokyo, Japan.  Lionrockk was moving toward the northeast at 6 m.p.h. (10 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 953 mb.

Typhoon Lionrock is very well organized.  It has a circular eye surrounded by a ring of strong thunderstorms.  Additional well formed spiral bands are rotating around outside the core of Lionrock.  Thunderstorms in the eyewall and spiral bands are generating upper level divergence which are pumping out mass in all directions.  The upper level divergence is inhibited a little on the far northern edge of the circulation by northerly winds impinging on Typhoon Lionrock.  Even so, there is enough upper level divergence to compensate for the strong inflow of mass near the surface and Typhoon Lionrock has been in a nearly steady state during recent hours.

Typhoon Lionrock is moving through an environment that should allow for it to maintain its intensity during the next severall days.  It is moving over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level high over China is generating northerly winds which are effecting the extreme northern edge of the outflow from Lionrock.  However, the vertical wind shear is not very strong and it should have a minimal effect on the intensity of the typhoon in the short term.  Eventually, Typhoon Lionrock will move over cooler SSTs and into a region where the upper level winds are stronger and it will start to weaken before it reaches Japan.

Typhoon Lionrock is moving around the western end of a subtropical ridge and that ridge is beginning to steer it toward the northeast.  That general motion is expected to continue for the next several days.  Eventually Lionrock is forecast to turn more toward the northwest.  On its anticipated track Typhoon Lionrock could approach the eastern coast of Honshu in three or four days.  Lionrock could still be a typhoon at that time.

If Lionrock makes landfall in Honshu as a typhoon it will be strong enough to cause some wind damage.  In addition, Typhoon Lionrock could move over some of the same areas affected by Typhoon Mindulle.  Heavy rain caused by Lionrock could create the potential for additional flash flooding and mudslides.

Lionrock Becomes a Typhoon East of Okinawa

Tropical Storm Lionrock intensified into a typhoon east of Okinawa on Tuesday.  At 8:00 p.m. EDT on Tuesday the center of Typhoon Lionrock was located at latitude 25.3°N and longitude 132.8°E which put it about 340 miles (550 km) east-southeast of Okinawa.  Lionrock was moving toward the south-southwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 965 mb.

Lionrock is a fairly small typhoon.  Winds to tropical storm force only extend out about 150 miles (240 km) from the center.  The circulation of Typhoon Lionrock is very well organized.  A small distinct eye is visible on satellite imagery.  The eye is surrounded by a ring of strong thunderstorms.  Additional spiral rainbands are rotating around the core of Lionrock.  The thunderstorms around the eye are generating upper level divergence which is pumping out mass in all directions.

Typhoon Lionrock is in an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30.5°C.  The upper level winds are weak and there is little vertical wind shear.  A small typhoon like Lionrock can intensify very quickly and it appears to be doing so.

An upper level ridge over China is steering Typhoon Lionrock slowly toward the south-southwest and that general motion is expected to continue for another day or two.  Lionrock could move into an area where the steering winds are weak and it could stall for a period of time.  Eventually, an upper level trough is expected to approach the area from the west and begin to pull Lionrock toward the north.

Tropical Storms Lionrock and Kompasu Spin Up Near Japan

A large cyclonic atmospheric gyre near Japan spun up two more tropical storms at the end of the week.  The Japan Meteorological Agency named two smaller circulations within the larger gyre Tropical Storm Lionrock and Tropical Storm Kompasu.

At 2:00 p.m. EDT on Saturday the center of Tropical Storm Kompasu was located at latitude 37.8°N and longitude 142.3°E which put it about 75 miles (120 km) east of Sendai, Japan.  Kompasu was moving toward the northwest at 26 m.p.h. (42 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 996 mb.

At 2:00 p.m. EDT on Saturday the center of Tropical Storm Lionrock was located at latitude 30.6°N and longitude 135.7°E which put it about 530 miles (860 km) east-northeast of Okinawa.  Lionrock was moving toward the west-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 994 mb.

Tropical Storm Kompasu is located farther north and it is beginning to make a transition into an extratropical cyclone.  Kompasu is moving over water where the Sea Surface Temperature (SST) is near 26°C, but it is moving rapidly toward cooler SSTs.  Most of the thunderstorms are in a single primary rainband that wraps around the southern part of the circulation.  An upper level trough west of Japan is pulling southwesterly winds across the top of Tropical Storm Kompasu and the vertical wind shear is increasing.

The upper level trough is expected to turn Tropical Storm Kompasu toward the northeast.  On its anticipated track Tropical Storm Kompasu will move across Hokkaido in about 18 hours.  It will bring locally heavy rain and some wind.

Tropical Storm Lionrock is more well organized.  Several spiral bands of thunderstorms are wrapping around the southern and east sides of the center of circulation.  There is drier air in the western portion of the circulation and there are few thunderstorms in that part of Lionrock.  The thunderstorms east of the center are generating upper level divergence that is pumping mass toward the northeast away from core of Tropical Storm Lionrock.

Tropical Storm Lionrock is in an environment that is somewhat favorable for additional intensification.  It is moving over water where the SST is near 30°C.  The upper level trough west of Japan is generating some vertical wind shear.  The drier air in the western part of the circulation will also inhibit intensification, but Lionrock could gradually get better organized.  Upper level outflow from stronger Tropical Storm Mindulle, which is southwest of Lionrock, could produce enough vertical wind shear to weaken Lionrock at times.

The large atmospheric gyre is steering Tropical Storm Lionrock toward the west-southwest.  Lionrock could be pulled more toward the south as the larger, stronger Tropical Storm Mindulle passes east of it.  Tropical Storm Lionrock is expected to remain south of Japan during the next several days.  An alternative scenario would be for Tropical Storm Mindulle to intensify into a typhoon and grow large enough to absorb the circulation of Lionrock.

Tropical Storm Nepartak Develops South of Guam

A center of circulation organized within an area of thunderstorms south of Guam and the system was designated Tropical Storm Nepartak.  At 11:00 p.m. EDT on Sunday the center of Tropical Storm Nepartak was located at latitude 12.2°N and longitude 141.4°E which put it about 215 miles (345 km) west-southwest of Guam.  Nepartak was moving northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 989 mb.

The circulation of Tropical Storm Nepartak is still organizing.  A primary rainband wrapped around the center and a circular area of thunderstorms formed at the core of the circulation.  The area of thunderstorms is generating upper level divergence which is pumping out mass and allowing the surface pressure to decrease.  Winds to tropical storm force extend our about 100 miles (160 km) from the center of circulation.

An upper level low located north of Nepartak is producing southwesterly winds which area blowing over the top of the tropical storm.  Those winds are creating some vertical wind shear, which is slowing the intensification of Nepartak.  However, the upper low is also enhancing upper level divergence to the northeast of the tropical storm.  Nepartak is moving over water where the Sea Surface Temperature is near 30°C.  The environment is favorable for intensification and Nepartak could become a hurricane during the next several days.

A subtropical ridge located northeast of Nepartak is steering the tropical storm toward the northwest.  That general motion is expected to continue during the next few days.  On its anticipated track, Nepartak could be approaching the southernmost islands of Japan in three or four days.  It is likely to be a typhoon at that time.

Dangerous Typhoon Koppu Making Landfall in Northern Luzon

Typhoon Koppu intensified rapidly during the past 12 hours and it is making landfall near Baler in northern Luzon as the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  At 11:00 a.m. EDT on Saturday the center of Typhoon Koppu was located at latitude 16.0°N and longitude 122.9°E which put it about 170 miles (275 km) east-northeast of Manila, Philippines.  Koppu was moving toward the west-northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 918 mb.  Typhoon Koppu has a Hurricane Intensity Index (HII) of 31.6, a Hurricane Size Index (HSI) of 17.5 and a Hurricane Wind Intensity Size Index (HWISI) of 49.1, which means it is capable of producing regional significant wind damage.  In addition the slow movement of Koppu means it will produce very heavy rainfall which will create the potential for serious flooding and landslides.

Koppu will continue to move toward the west-northwest for another 12 to 24 hours.  Then it will reach the western end of the subtropical ridge that has been steering it and start to move toward the north.  Although Typhoon Koppu will weaken as it moves across northern Luzon, it will be over that area for 36 to 48 hours.  Koppu has the potential to cause widespread damage due to winds, floods and landslides.

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.

Tropical Storm Dujuan Intensifying Southeast of Okinawa

After several days where vertical wind shear pushed most of the thunderstorms west of the core of the circulation, Tropical Storm Dujuan began to intensify on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Dujuan was located at latitude 18.9°N and longitude 132.7°E which put it about 620 miles (1000 km) southeast of Okinawa.  Dujuan was moving toward the west-northwest at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 60 m.p.h. (95 km/h) and there were wind gusts to 75 m.p.h. (120 km/h).  The minimum surface pressure was 988 mb.

The circulation near the core of Tropical Storm Dujuan is showing more organization.  Thunderstorms are developing closer to the center of circulation, although most of the stronger storms are still south and southwest of the center.  The distribution of thunderstorms is an indication that an upper level ridge west of Dujuan is still generating northeasterly winds over the top of the tropical storm.  Some of the storms closer to the center of circulation are starting to generate upper level divergence.

Dujuan is over water where the Sea Surface Temperatures are near 30°C.  Intensification is likely but vertical wind shear could limit the rate of intensification in the short term.  The wind shear is likely to decrease in a day or two as Dujuan moves into an area where the upper level winds are lighter.  Dujuan could become a typhoon within 24 to 36 hours and it could reach the equivalent of a major hurricane during the weekend.

Tropical Storm Dujuan is being steered toward the west-northwest by a subtropical ridge located to its northeast,  That general steering patter is expected to continue for another 24 to 36 hours.  At that time Dujuan will be between the ridge to its east and another upper level ridge to its west, and it could turn toward the northwest for a day or so.  The western ridge is expected to build north of Dujuan and turn it more toward the west in three or four days.  On its anticipated track Dujuan could approach the southern islands of Japan in three or four days.  It could be near Taiwan in five days.  Dujuan could be a strong typhoon by that time.

Typhoon Goni Passing West of Okinawa

The center of powerful Typhoon Goni is passing west of Okinawa.  At 11:00 p.m. EDT on Sunday the center of Typhoon Goni was located at latitude 26.9°N and longitude 126.3°E which put it about 125 miles (200 km) west of Okinawa.  Goni was moving northeast at 18 m.p.h. (29 km/h).  The maximum sustained wind speed 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 937 mb.

An upper level trough northwest of Goni contributed to the development of an outflow channel which pumped out mass and allowed the typhoon to intensify on Sunday.  Goni is a strong well organized typhoon with an eye and a well formed eyewall.  Spiral bands of thunderstorms are rotating around the core of the circulation.  A weather station on Ishigaki Jima, Japan reported a wind gust to 97 m.p.h. (155 km/h) when Goni passed over the island.  Goni is moving over warm Sea Surface Temperatures (SSTs) and it could maintain its intensity for another 24 hours.  After that time it will move over cooler SSTs and the upper level trough will generate more vertical wind shear.  Goni will finally start to spin down when it moves west of Kyushu.

The upper level trough will continue to pull Goni toward the northeast.  On its anticipated track Typhoon Goni will approach western Kyushu in about 24 hours.  It could bring strong winds and heavy rain to parts of western Japan.

Typhoon Goni Heading Toward Western Japan

Typhoon Goni turned north-northeastward and began moving toward western Japan on Saturday.  At 5:00 p.m. EDT on Saturday the center of Typhoon Goni was located at latitude 22.7°N and longitude 123.4°E which put it about 270 miles (435 km) southeast of Taipei, Taiwan and about 410 miles (660 km) southwest of Okinawa.  Goni was moving toward the north-northeast at 11 m.p.h. (18 km/h).  The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h).  The minimum surface pressure was 967 mb.

The circulation of Typhoon Goni continues to be well organized.  It has a small eye with a fairly continuous eyewall surrounding it.  There are multiple spiral bands and the strongest band is about 60 miles east of the center of circulation.  There is upper level divergence pumping out mass.  Goni is moving over warm Sea Surface Temperatures and the upper level winds are relatively light.  The environment is favorable for intensification and modest intensification is possible during the next day or so.

Goni is moving around the western end of a subtropical ridge which is steering it toward the north-northeast.  That steering pattern is expected to continue for another two or three days.  On its anticipated track Goni will be near Ishigaki Jima in about 12 hours.  It could be just west of Okinawa in about 30 hours and it could be approaching Kyushu in about 48 hours.  Goni will bring strong winds and heavy rains to any places in its path.