Category Archives: Tropical Cyclones

Information about tropical cyclones

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.

Ernesto Makes Transition to Tropical Storm

Former Subtropical Storm Ernesto made a transition to a tropical storm on Thursday afternoon.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Ernesto was located at latitude 43.0°N and longitude 41.0°W which put it about 645 miles (1035 km) east-southeast of Cape Race, Newfoundland.  Ernesto was moving toward the northeast at 18 m.p.h. (30 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 1007 mb.

Even though now Tropical Storm Ernesto moved over water where the Sea Surface Temperature was between 24°C and 25°C, there was enough energy in the upper ocean to cause more thunderstorms to develop.  In addition, many of the thunderstorms developed close to the center of circulation.  The inner bands of showers and thunderstorms became stronger and the bands in the outer parts of the circulation weakened.  Ernesto exhibited a structure like a tropical cyclone and the National Hurricane Center classified the system as a tropical storm in the 5:00 p.m. EDT advisory.

Tropical Storm Ernesto will move over much cooler water during the next 24 hours.  It is likely to make a transition to an extratropical cyclone when it moves over the cooler water.  Ernesto could strengthen when colder air is pulled into the western half of the circulation and a cold front forms south of the center.  The development of the cold front and upper level divergence could strengthen the pressure gradient force which would give the air a stronger push.  An upper level trough east of the U.S. is forecast to steer Ernesto in the general direction of Ireland and the United Kingdom.

Tropical Storm Lane Forms Southwest of Baja Califonia

Tropical Storm Lane formed southwest of Baja California on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Lane was located at latitude 10.7°N and longitude 123.6°E which put it about 1235 miles (1990 km) southwest of the southern tip of Baja California.  Lane was loving 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 1006 mb.

A distinct low level center of circulation formed on Wednesday morning within a tropical wave southwest of Baja California.  The National Hurricane Center designated the system as Tropical Storm Lane when more thunderstorms formed near the center of circulation.  The circulation of Tropical Storm Lane was organizing quickly.  Thunderstorms were developing around the center of circulation.  Bands of showers and thunderstorms began to form and to revolve around the core of Tropical Storm Lane.  Storms in the core started to generate upper level divergence which was pumping mass away from the tropical storm in all directions.

Tropical Storm Lane will move through an environment very favorable for intensification.  Lane 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.  Tropical Storm Lane will intensify and it could become a hurricane within 36 hours.  When an eye forms and the core of the circulation is well established, Lane could intensify rapidly and it could strengthen into a major hurricane by the weekend.

Tropical Storm Lane will move south of the subtropical ridge over the Eastern North Pacific.  The ridge will steer Lane westward.  On its anticipated track Tropical Storm Lane will move farther away from Baja California and in the general direction of Hawaii.

Subtropical Storm Ernesto Forms West of the Azores

Subtropical Storm Ernesto formed west of the Azores on Wednesday morning.  At 11:00 a.m. EDT on Wednesday the center of Subtropical Storm Ernesto was located at latitude 38.1°N and longitude 46.0°W which put it about 695 miles (1120 km) southeast of Cape Race, Newfoundland.  Ernesto was moving toward the north 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 1008 mb.

More thunderstorms formed closer to the center of a low pressure system west of the Azores on Wednesday morning and the National Hurricane Center designated the system as Subtropical Storm Ernesto.  Several bands of showers and thunderstorms wrapped around the eastern and northern portions of the circulation.  Bands northwest of the center of Ernesto consisted primarily of showers and lower clouds.  The circulation may have been transporting some cooler, drier, more stable air into that part of the circulation.  Showers and thunderstorms around the center of Ernesto were generating upper level divergence which was pumping mass away to the northeast of the subtropical storm.

Subtropical Storm Ernesto will move through an environment that could support some intensification during the next day or so.  Ernesto will move over water where the Sea Surface Temperature is near 26°C.  It will move through a region where the upper level winds are not too strong and there will not be much vertical wind shear.  Subtropical Storm Ernesto could strengthen during the next 12 to 24 hours.  Ernesto will move over cooler water later on Thursday and it will start to weaken.  An upper level trough east of the U.S. will approach Subtropical Storm Ernesto from the west.  Southwesterly winds ahead of the trough will cause more vertical wind shear and Ernesto could make a transition to an extratropical cyclone.

The southwesterly winds ahead of the upper level trough will steer Subtropical Storm Ernesto in a general northeasterly direction.  On its anticipated track Subtropical Ernesto will pass between the Azores and Greenland.

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.

Hurricane Hector Passes South of Hawaii

Powerful Hurricane Hector passed south of Hawaii on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane Hector was located at latitude 16.7°N and longitude 156.8°W which put it about 325 miles (525 km) south-southeast of Honolulu, Hawaii.  Hector was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 135 m.p.h. (220 km/h).  The minimum surface pressure was 959 mb.

The circulation of Hurricane Hector remained circular and symmetrical.  Information from radar and satellites indicated that Hurricane Hector had a double eyewall structure.  There was a small inner eye surrounded by an inner eyewall.  The inner eyewall was thin and it appeared to be weakening.  A clear area, sometimes called a moat, surrounded the inner eyewall.  A second thicker eyewall surrounded the moat.  Several shorter bands of of showers and thunderstorms were revolving around the core of Hector.  The circulation of Hurricane Hector was relatively small.  Winds to hurricane force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force only extended out about 95 miles (155 km) from the center.

Hurricane Hector exhibited a structure that is sometimes called an annular hurricane.  Annular hurricanes often achieve an equilibrium with their environment which can persist for days if there is not much wind shear.  Hector will move over water where the Sea Surface Temperature is between 27°C and 28°C.  It will move through a region where there is little vertical wind shear.  Hurricane Hector will remain a strong hurricane and it could strengthen during the next 24 to 48 hours, if the inner eyewall dissipates completely.

Hurricane Hector will move south of the subtropical high pressure system over the Central Pacific.  The high will steer Hector toward the west for several more days.  On its anticipated track Hurricane Hector will remain south of Hawaii.

Elsewhere over the Eastern North Pacific Ocean, Hurricane John weakened west of Baja California and Tropical Storm Kristy exhibited little change on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Hurricane John was located at latitude 23.1°N and longitude 114.4°W which put it about 285 miles (460 km) west of the southern tip of Baja California.  John was moving toward the northwest at 16 m.p.h. (26 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 983 mb.

At 11:00 p.m. EDT on Wednesday the center of Tropical Storm Kristy was located at latitude 15.3°N and longitude 130.0°W which put it about 1410 miles (2220 km) west-southwest of the southern tip of Baja California.  Kristy was moving toward the northwest at 7 m.p.h. (11 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 1002 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.

Debby Makes a Transition to a Tropical Storm

Former Subtropical Storm Debby made a transition to a tropical storm on Wednesday.  At 11:00 a.m. EDT on Wednesday the center of Tropical Storm Debby was located at latitude 41.2°N and longitude 48.3°W which put it about 1150 miles (1855 km) west-northwest of the Azores.  Debby was moving toward the northeast at 12 m.p.h. (19 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 1003 mb.

The structure of former Subtropical Storm Debby changed on Wednesday and it exhibited the characteristics of a tropical storm.  More thunderstorms formed around the center of circulation and those thunderstorms rose higher into the atmosphere.  Additional bands of showers and thunderstorms developed and revolved around the core of the circulation.  Storms near the core began to generate upper level divergence.  The strongest winds occurred closer to the center of circulation.  The National Hurricane Center designated Debby as a tropical storm based on information from satellites.

Tropical Storm Debby will move into an environment unfavorable for a tropical storm during the next 24 to 48 hours.   Debby was over water where the Sea Surface Temperature was near 26°C, but it will soon move over much cooler water.  It will start to weaken when it moves over the cooler water.  It could take several days for the circulation around Tropical Storm Debby to spin down.

Tropical Storm Debby will be steered toward the northeast as it moves between an upper level trough to the west and an upper level ridge to the east.  On its anticipated track Tropical Storm Debby will move between the Azores and Greenland.