Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Tropical Storm Rumbia Makes Landfall Near Shanghai, Bebinca Hits Vietnam

Tropical Storm Rumbia made landfall on the east coast of China just south of Shanghai on Thursday, and Tropical Storm Babinca hit Vietnam.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Rumbia was located at latitude 30.5°N and longitude 121.0°E which put it about 60 miles (95 km) southwest of Shanghai, China.  Rumbia was moving toward the west at 14 m.p.h. (22 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 987 mb.

Tropical Storm Rumbia strengthened before it made landfall.  Thunderstorms developed near the center of circulation and a band wrapped around the center.  The circulation became more circular and storms near the center began to generate upper level divergence.  In the western half off the circulation where the winds were blowing toward the land, increased friction enhanced rising motion and heavier rain fell.

Tropical Storm Rumbia caused some gusty winds near the coast, but the greater risks were the locally heavy rain and the potential for floods.  Tropical Storm Rumbia is forecast to move slightly north of due west as it moves inland over eastern China.  Rumbia will drop locally heavy rain over the area around Shanghai, and over parts Zhejiang, Jiangsu and Anhui provinces.  Some of those regions have received heavy rain from previous storms and the potential for serious flooding exists.

Tropical Storm Bebinca made landfall on the coast of Vietnam on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Bebinca was located at latitude 19.9°N and longitude 106.3°E which put it about 70 miles (110 km) southeast of Ninh Binh, Vietnam.  Bebinca was moving toward the west-southwest at 8 m.p.h. (13 km/h).  The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h).  The minimum surface pressure was 979 mb.

Tropical Storm Bebinca also strengthened before it made landfall.  An eye started to form at the center of circulation and Bebinca was on the threshold of becoming a typhoon when it made landfall.  Tropical Storm Bebinca produced gusty winds and a storm surge near the coast.  However, the greatest risks are locally heavy rain and the potential for floods.  Tropical Storm Bebinca is forecast to move in a general westerly direction.  Bebinca will drop locally heavy rain over parts of Vietnam, northern Laos and extreme northern Thailand.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Soulik moved quickly toward Iwo To and strengthened.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Soulik was located at latitude 20.9°N and longitude 141.3°E which put it about 315 miles (510 km) south of Iwo To.  Soulik was moving toward the north at 20 m.p.h. (32 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 981 mb.

Tropical Storm Leepi Approaches Kyushu

Tropical Storm Leepi approached Kyushu late on Monday.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Leepi was located at latitude 29.8°N and longitude 135.3°E which put it about 335 miles (545 km) east-southeast of Kagoshima, Japan.  Leepi was moving toward the northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h).  The minimum surface pressure was 983 mb.

The circulation of Tropical Storm Leepi became much better organized on Monday.  A large circular clear area formed at the center of circulation, which represented the formation of an eye.  A primary band of showers and thunderstorms wrapped most of the way around the formative eye and the strongest winds were occurring in that band of storms.  Several bands of showers and thunderstorms in the eastern half of the circulation were revolving around the core of Tropical Storm Leepi.  Bands northwest of the center consisted mostly of showers and lower clouds.  Winds to tropical storm force extend out about 110 miles (170 km) from the center of circulation.  Storms around the center of Tropical Storm Leepi were generating upper level divergence that was pumping mass away from the tropical storm.

Tropical Storm Leepi will move through an environment that will become less favorable on Tuesday.  Leepi will move over water where the Sea Surface Temperature is near 28°C which means there will be enough energy to support a strong tropical storm.  However, an upper level ridge northwest of Japan will produce northeasterly winds which will cause significant vertical wind shear.  The wind shear will cause Tropical Storm Leepi to start to weaken when it nears Japan.

The ridge northwest of Japan will steer Tropical Storm Leepi toward the northwest on Tuesday.  On its anticipated track the center of Tropical Storm Leepi will reach southeastern Kyushu in about 18 hours.  Leepi will bring gusty winds and locally heavy rain to Kyushu late on Tuesday.  The locally heavy rain could create the potential for flash floods.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Bebinca meandered southwest of Hong Kong and Tropical Storm Hector move westward across the International Date Line.  At 11:00 p.m. EDT on Monday the center of Tropical Storm Bebinca was located at latitude 21.1°N and longitude 113.8°E which put it about 100 miles (160 km) south-southwest of Hong Kong.  Bebinca was moving toward the north-northeast at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95km/h).  The minimum surface pressure was 989 mb.

At 11:00 p.m. EDT on Monday the center of Tropical Storm Hector was located at latitude 26.2°N and longitude 176.2°E which put it about 760 miles (1225 km) east-northeast of Wake Island.  Hector was moving toward the west at 18 m.p.h. (29 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 1003 mb.

Tropical Storm Yagi Makes Landfall on East Coast of China

Tropical Storm Yagi made landfall on the east coast of China between Wenzhou and Taizhou on Sunday.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Yagi was located at latitude 28.4°N and longitude 121.7°E which put it about 35 miles (55 km) south of Taizhou, China.  Yagi was moving toward the 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 987 mb.

Tropical Storm Yagi was moving steadily inland over Zhejiang province between Wenzhou and Taizhou.  The strongest winds were occurring in bands of thunderstorms east of the center of circulation that were over the coastal waters of the East China Sea.  The wind in those areas will diminish when Yagi moves farther inland.  The greatest risk will be locally heavy rain falling over parts of Zhejiang province.  Rainfall could be enhanced where the wind blows up the slopes of mountains and steep terrain increases the potential for flash floods.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Leepi moved closer to Iwo To and Tropical Depression 20W formed southwest of Hong Kong.  At 11:00 a.m. EDT on Sunday the center of Tropical Storm Leepi was located at latitude 24.1°N and longitude 141.2°E which put it about 85 miles (135 km) south-southeast of Iwo To.  Leepi was moving toward the north-northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 55 m.p.h. (90 km/h) and there were wind gusts to 70 m.p.h. (110 km/h).  The minimum surface pressure was 992 mb.

At 11:00 a.m. EDT on Sunday the center of Tropical Depression 20W was located at latitude 20.7°N and longitude 112.4°E which put it about 85 miles (135 km) southwest of Macao.  It was moving toward the east-southeast at 3 m.p.h. (5 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 996 mb.

Tropical Storm Leepi Forms Southeast of Iwo To

Tropical Storm Leepi formed southeast of Iwo To on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Leepi was located at latitude 21.5°N and longitude 142.7°W which put it about 285 miles (465 km) south-southeast of Iwo To.  Leepi was moving toward the north-northwest at 12 m.p.h. (19 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 995 mb.

A distinct center of circulation developed within an area of thunderstorms between the Northern Marianas and Iwo To and the Japan Meteorological Agency designated the system as Tropical Storm Leepi.  The distribution of thunderstorms around Tropical Storm Leepi was very asymmetrical.  The stronger thunderstorms were all occurring in bands in the eastern half of the circulation.  The bands in the western half of the circulation consisted of showers and low clouds.  Storms near the center of Leepi were generating upper level divergence which was pumping mass away to the northeast of the tropical storm.

Tropical Storm Leepi will move through an environment somewhat favorable for intensification during the next 12 to 24 hours.  Leepi will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough northeast of the tropical storm was producing southwesterly winds which were causing moderate vertical wind shear.  The wind shear was inhibiting the divergence to the west of Tropical Storm Leepi.  The tropical storm also appeared to be drawing drier air into the western side of the circulation.  Leepi could intensify on Sunday, but it will move into an area of stronger upper level winds in a day or so.  Increased vertical wind shear will likely start to weaken Tropical Storm Leepi after that occurrs.

Tropical Storm Leepi will move near the western end of a ridge in the middle troposphere.  The ridge will Leepi in a general motion toward the northwest.  On its anticipated track Tropical Storm Leepi will move near Iwo To in about 24 hours.  Leepi could approach the northern Ryukyu Islands and Kyushu in about three days.

Elsewhere over the Western North Pacific, Tropical Storm Yagi passed over the southern Ryukyu Islands on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Storm Yagi was located at latitude 25.6°N and longitude 124.8°E which put it about 250 miles (400 km) east of Taipei, Taiwan.  Yagi was moving toward the west at 14 m.p.h. (22 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 993 mb.

Typhoon Shanshan Brushes East Coast of Honshu

Typhoon Shanshan brushed the east coast of Honshu late on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Shanshan was located at latitude 36.8°N and longitude 141.5°E which put it about 40 miles (65 km) east of Iwaki, Japan.  Shanshan was moving toward the north at 12 m.p.h. (19 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.

The center of Typhoon Shanshan moved very close to the east coast of Honshu near Choshi on Wednesday and then it moved nearly parallel to the coast.  The stronger winds and heavier rain were occurring on the eastern side of Shanshan, and they passed east of Honshu.  The winds were weaker and the rain was lighter in the western side of Typhoon Shanshan.  Winds to tropical storm force were occurring near the east coast of Honshu.  The typhoon had little effect on the weather near Tokyo.  Some locations near the coast did have a period of heavier rain after the center of Typhoon Shanshan passed and the winds blew from the southwest toward the coast.

Typhoon Shanshan will affect the coast of Honshu for another six to twelve hours, while the center moves nearly parallel to the coast.  Shanshan will reach an area where stronger westerly winds are blowing in the middle and upper troposphere.  Those winds will turn Typhoon Shanshan toward the east and they will push it away from Japan.  The stronger winds will also cause significant vertical wind shear.  Shanshan will move over cooler water when it turns eastward.  The combination of vertical wind shear and cooler water will cause Typhoon Shanshan to weaken and it could make a transition to an extratropical cyclone in a day or two.

Elsewhere over the Western North Pacific, Tropical Storm Yagi formed southeast of Okinawa on Wednesday.  At 11:00 p.m. EDT the center of Tropical Storm Yagi was located at latitude 21.3°N and longitude 133.6°E which put it about 530 miles (855 km) southeast of Okinawa.  Yagi was moving toward the northwest at 7 m.p.h. (11 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 993 mb.

Typhoon Shanshan Moves Closer to Honshu

Typhoon Shanshan moved steadily closer to Honshu on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Typhoon Shanshan was located at latitude 33.7°N and longitude 141.6°E which put it about 190 miles (305 km) southeast of Tokyo.  Shanshan was moving toward the north-northwest at 12 m.p.h. (19 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 965 mb.

Typhoon Shanshan intensified earlier on Tuesday and it started to weaken on Tuesday night.  There was a circular eye at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Typhoon Shanshan.  The rainbands south and east of the center were stronger and the rainbands north and west of the center were weaker.  Storms near the core of Shanshan were generating upper level divergence which was pumping mass away from typhoon.  Winds to typhoon force extended out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 220 miles (350 km) from the center.

Typhoon Shanshan will move through an environment on Wednesday that should allow it to remain a typhoon until it reaches Japan.  Shanshan will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weaker and there will be little vertical wind shear.  Typhoon Shanshan will move into a region in a day or so where stronger upper level winds will blow from the west.  Vertical wind shear will increase at that time and Typhoon Shanshan will start to weaken more quickly.

Typhoon Shanshan will move around the western end of a ridge over the North Pacific Ocean and the ridge will steer the typhoon toward the north on Wednesday.  When Shanshan gets close to the coast of Honshu, the westerly winds will turn the typhoon toward the east.  On its anticipated track Typhoon Shanshan could make landfall on the coast of Honshu east of Tokyo in 18 to 24 hours.  Shanshan will bring gusty winds and it could drop heavy rain over coastal regions of eastern Honshu.

Typhoon Shanshan Moves Toward Japan

Typhoon Shanshan moved toward Japan on Monday.  At 11:00 a.m. EDT on Monday the center of Typhoon Shanshan was located at latitude 29.2°N and longitude 145.3°E which put it about 585 miles (940 km) southeast of Tokyo, Japan.  Shanshan was moving toward the north-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 95 m.p.h. (155 km/h).  The minimum surface pressure was 971 mb.

Typhoon Shanshan weakened slightly during the past 24 hours.  It appeared that some drier air may have been pulled into the western half of the circulation.  There was still a circular eye at the center of circulation, but there were breaks in the ring of thunderstorms around the eye.  There were several bands of stronger storms in the eastern and southern parts of the circulation.  Bands north and west of the center of Shanshan consisted primarily of showers and lower clouds.  Storms in the core were generating strong upper level divergence which was pumping mass away from the typhoon.

Typhoon Shanshan will move through an environment that should allow it to remain a typhoon for several more days.  Shanshan will move over water where the Sea Surface Temperature is near 28°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Drier air north and west of Typhoon Shanshan will inhibit the formation of taller thunderstorms in that part of the typhoon and the drier air will limit the potential for intensification.

Typhoon Shanshan will move around the western side of a subtropical ridge over the North Pacific Ocean.  The ridge will steer Shanshan in a general north-northwesterly direction for another two or three days.  When Typhoon Shanshan nears Honshu, an southwesterly winds on the east side of an upper level trough will start to steer the typhoon toward the northeast.  There is still uncertainty about when and where the turn toward then northeast will occur and Typhoon Shanshan could be close to Tokyo in about three days.

Shanshan Strengthens to a Typhoon Southeast of Japan

Former Tropical Storm Shanshan strengthened into a typhoon southeast of Japan on Saturday.  At 5:00 a.m. EDT on Saturday the center of Typhoon Shanshan was located at latitude 21.2°N and longitude 148.5°E which put it about 245 miles (395 km) northeast of Agrihan.  Shashan was moving toward the north-northwest at 10 m.p.h. (16 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.

A primary rainband wrapped around the center of circulation and an eye was developing at the center of Typhoon Shanshan.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Shanshan.  The strongest rainbands were south and east of the center of circulation.  Bands north and west of the center consisted primarily of showers and lower clouds.  Storms around the core were generating upper level divergence which was pumping mass away from the typhoon.  Shanshan has a large circulation.  Winds to tropical storm force extend out about 190 miles (305 km) from the center of circulation.

Typhoon Shanshan will move through an environment favorable for intensification during the next 24 to 48 hours.  Shanshan will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Shanshan will intensify and it could strengthen into the equivalent of a major hurricane.

Typhoon Shanshan will move around the western portion of a subtropical ridge over the Western North Pacific Ocean.  The ridge will steer Shanshan in a north-northwesterly direction.  On its anticipated track the center of Typhoon Shanshan will pass east of Iwo To in 24 to 36 hours.  Shanshan could be just southeast of Honshu in about four days.

Tropical Storm Jongdari Makes Landfall South of Shanghai, Shanshan Forms Northeast of Guam

Tropical Storm Jongdari made landfall south of Shanghai on Thursday, while Tropical Storm Shanshan formed northeast of Guam.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Jongdari was located at latitude 30.7°N and longitude 121.4°E which put it about 40 miles (65 km) south of Shanghai, China.  Jongdari was moving toward the west at 19 m.p.h. (30 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.

The center of Tropical Storm Jongdari made landfall on the east coast of China near Zhoushan and Ningbo on Thursday.  Jongdari retained a distinct low level center of circulation while it made landfall.  The tropical storm brought gusty winds to the coast of Zhejiang and Shanghai Shi provinces.  Tropical Storm Jongdari dropped locally heavy rain over parts of those provinces and some flooding could occur.  The center of Jongdari will move quickly toward Hangzhou and the risk of flooding will continue as the tropical storm moves inland and weakens.

Elsewhere over the Western North Pacific Ocean, Tropical Storm Shanshan formed northeast of Guam.  At 11:00 p.m. EDT on Thursday the center of Tropical Storm Shanshan was located at latitude 17.9°N and longitude 150.1°E which put it about 460 miles (740 km) northeast of Guam.  Shanshan was moving toward the west-southwest at 7 m.p.h. (11 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. (65 km/h).  The minimum surface pressure was 998 mb.

A distinct low level center of circulation formed in a cluster of thunderstorms east of the Northern Marianas on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Shanshan.  The circulation of Shanshan was still organizing.  Several bands of showers and thunderstorms developed southwest of the center of circulation.  Bands northeast of the center consisted mostly of showers and lower clouds.  Storms near the center of circulation started to generate upper level divergence.

Tropical Storm Shanshan will move through an environment favorable for intensification.  Shanshan will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Storm Shanshan will intensify and it could strengthen into a typhoon during the weekend.

Tropical Storm Shashan will move around the western end of a subtropical high pressure system.  The high will steer Shanshan in a general northwesterly direction during the next 12 to 24 hours.  It will turn more toward the north during the weekend.  On its anticipated track Tropical Storm Shanshan will move near the Northern Marianas during the next 24 to 36 hours.

Tropical Storm Jongdari Heads Toward China

Tropical Storm Jongdari headed toward China late on Tuesday.  After dropping heavy rain on parts of Honshu and Kyushu, former Typhoon Jongdari weakened to a tropical storm.  Jongdari then was caught by the circulation of an upper level low south of Japan and the tropical storm made a slow counterclockwise loop south of Kyushu.  Tropical Storm Jongdari completed the loop and moved west toward China on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Jongdari was located at latitude 30.0°N and longitude 126.7°E which put it about 360 miles (575 km) east-southeast of Shanghai, China.  Jongdari was moving toward the west at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 990 mb.

Tropical Storm Jongdari moved around the circulation of an upper level low south of Japan on Sunday and Monday.  Strong upper winds rotating around the upper level low caused vertical wind shear which disrupted the upper part of Jongdari’s circulation.  However, the integrity of the lower level circulation remained intact.  There is a well defined low level circulation with bands of showers and thunderstorms revolving around the center of circulation.  Stronger upper level winds have periodically sheared the tops off of the taller thunderstorms.  New thunderstorms were forming near the center of circulation but it is unclear if those storms will persist.

Tropical Storm Jongdari will move through an environment marginally favorable for intensification on Wednesday.  Jongdari will move over water where the Sea Surface Temperature is near 28°C.  However the upper level low south of Japan and an upper level ridge over East Asia will combine to produce strong easterly winds which will blow across the top of the circulation.  Those winds will cause strong vertical wind shear which will inhibit intensification.  Tropical Storm Jongdari could intensify a little during the next 24 hours.

Tropical Storm Jongdari will move south of a high pressure system near East Asia which will steer Jongdari in a general westerly direction.  On its anticipated track Tropical Storm Jongdari could approach the coast of China southeast of Shanghai in about 24 hours.  The center of Jongdari could be near Shanghai in about 36 hours.  Tropical Storm Jongdari will bring some gusty winds, but the greater risk will be locally heavy rainfall.  Heavy rain falling on very moist ground could cause flash floods over parts of eastern China.