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.

Hurricane John Absorbs Ileana, Tropical Storm Kristy Forms

The much stronger and larger circulation of Hurricane John absorbed the smaller and weaker Tropical Storm Ileana south of Baja California on Tuesday morning, while Tropical Storm Kristy formed farther west over the Eastern North Pacific Ocean.  At 5:00 p.m. EDT on Tuesday the center of Hurricane John was located at latitude 18.7°N and longitude 110.5°W which put it about 295 miles (470 km) south of the southern tip of Baja California.  John was moving toward the northwest at 10 m.p.h. (17 km/h).  The maximum sustained wind speed was 105 m.p.h. (165 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 969 mb.

The circulation of Hurricane John is well organized.  A circular eye is at the center of circulation.  A ring of stronger thunderstorms wraps around the eye.  The strongest storms are in the eastern half of the ring and that is where the strongest winds are occurring.  Several bands of showers and thunderstorms are revolving around the core of Hurricane John.  The strongest bands are south and east of the center of circulation.  The bands north and west of the center are weaker and there is cooler water in that area.  Storms around the core of the circulation are generating strong upper level divergence which is pumping mass away from the hurricane.

Hurricane John will move through an environment favorable for intensification on Wednesday.  John will move over water where the Sea Surface Temperature is near 29°C.  It will move through an area where the upper level winds are weak.  Hurricane John could intensify on lWednesday and it has a chance to strengthen into a major hurricane.  John will start to move over cooler water in 24 to 36 hours and it will start to weaken when that happens.

Hurricane John will move around the western side of a ridge in the middle troposphere.  The ridge will steer John toward the northwest during the next day or two.  On its anticipated track the core of Hurricane John will pass west of Baja California.  Rainbands north of the center of Hurricane John could drop locally heavy rain over parts of Baja California and there will be a risk of flash floods.  Hurricane John could push higher surf along the west coast of Baja California toward southern California.

Elsewhere over the Eastern North Pacific, Tropical Storm Kristy formed southwest of Hurricane John on Tuesday morning.  At 5:00 p.m. EDT on Tuesday the center of Tropical Storm Kristy was located at latitude 13.7°N and longitude 127.1°W which put it about 1290 miles (2080 km) west-southwest of the southern tip of Baja California.  Kristy was moving toward the west at 13 m.p.h. (20 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 1000 mb.  There is much uncertainty about whether or not the circulation of Tropical Storm Kristy will be affected by the circulation of Hurricane John.

Subtropical Storm Debby Forms West of the Azores

Subtropical Storm Debby formed over the North Atlantic Ocean west of the Azores on Tuesday morning.  At 11:00 a.m. EDT on Tuesday the center of Subtropical Storm Debby was located at latitude 38.9°N and longitude 48.5°W which put it about 1160 miles (1870 km) west of the Azores.  Debby was moving toward the north at 16 m.p.h. (26 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.

A surface low pressure system revolved around the western side of an upper level low over the North Atlantic Ocean during the past few days.  More bands of showers and thunderstorms developed around the surface low on Tuesday morning and its circulation become more circular.  The National Hurricane Center designated the low pressure system as Subtropical Storm Debby based on satellite imagery.  The strongest winds were occurring in a rainband that wrapped around the northern side of the circulation.  Bands south of the center of circulation consisted primarily of showers and lower clouds.

Subtropical Storm Debby will move through an environment somewhat favorable for intensification during the next 24 hours.  Debby will move over water where the Sea Surface Temperature is between 26°C and 27°C.  Subtropical Storm Debby will move between an upper level trough to its west and an upper level ridge to its east.  The trough and ridge will produce southeasterly winds which will cause moderate vertical wind shear.  Subtropical Storm Debby could strengthen during the next 24 hours.  Debby will move over much colder water in about 36 hours and then it will weaken.

The upper level ridge and trough will steer Subtropical Storm Debby in a mainly northerly direction.  On its anticipated track Subtropical Storm Debby will remain west of the Azores.

Recon Finds Hurricane Hector Nearly at Category 5

An Air Force Reserve Hurricane Hunter reconnaissance aircraft found on Monday that Hurricane Hector had strengthened to nearly Category 5 on the Saffir-Simpson Scale.  At 5:00 p.m. EDT on Monday the center of Hurricane Hector was located at latitude 15.2°N and longitude 143.1°W which put it about 870 miles (1405 km) east-southeast of South Point, Hawaii.  Hector was moving toward the west at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 155 m.p.h. (250 km/h) and there were wind gusts to 190 m.p.h. (305 km/h).  The minimum surface pressure was 936 mb.  A Tropical Storm Watch is in effect for Hawaii County.

Hurricane Hector has a very symmetrical, well formed circulation.  There is a circular eye with a diameter of 19 miles (31 km) at the center of circulation.  The eye is 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 Hurricane Hector.  Storms near the core were generating well developed upper level divergence which was pumping mass away from the hurricane in all directions.

The circulation of Hurricane Hector is compact.  Winds to hurricane force extend out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force extend out about 105 miles (170 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Hector is 33.3.  The Hurricane Size Index (HSI) is 12.1 and the Hurricane Wind Intensity Size Index (HWISI) is 45.4.

Hurricane Hector will remain in its current environment for several more days.  Hector will move over water where the Sea Surface Temperature is near 27°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  If a rainband wraps around the eye and eyewall, then an eyewall replacement cycle could occur.  Eyewall replacement cycles cause weakening at first while the inner eyewall dissipates.  Hurricanes can restrengthen if the outer eyewall starts for move closer to the center of circulation.  Most very powerful hurricanes only stay very intense for 12 to 24 hours before they start to weaken.  If takes a lot of energy to drive an intense hurricane and if Hector moves into an environment that is a little less favorable, then it could weaken.

Hurricane Hector will move south of the subtropical high pressure system over the Eastern and Central North Pacific Ocean.  The subtropical high will steer Hector in a general westerly direction during the next few days.  On its anticipated track Hurricane Hector will be southeast of Hawaii by Wednesday morning.  The core of Hurricane Hector is forecast to pass south of Hawaii, but it could come close enough to cause tropical storm force winds which is the reason for the Tropical Storm Watch.

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.

Powerful Hurricane Hector Approaches Central Pacific, Ileana Forms South of Mexico

Powerful Hurricane Hector approached the Central Pacific Ocean on Sunday while Tropical Storm Ileana and Tropical Depression Twelve-E formed south of Mexico.  The government of Mexico issued a Tropical Storm Watch for a portion of the coast because of the potential impacts of Tropical Storm Ileana.  At 8:00 p.m. EDT on Sunday the center of Hurricane Hector was located at latitude 14.5°N and longitude 138.6°W which put it about 1170 miles (1885 km) east-southeast of South Point, Hawaii.  Hector was moving toward the west at 13 m.p.h. (20 km/h).  The maximum sustained wind speed was 140 m.p.h. (220 km/h) and there were wind gusts to 165 m.p.h. (270 km/h).  The minimum surface pressure was 947 mb.

The circulation of Hurricane Hector was very well organized.  There was a circular eye with a diameter of 18 miles (29 km) 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 Hurricane Hector.  Storms in the core of Hector were generating strong upper level divergence which was pumping mass away from the hurricane.

The circulation of Hurricane Hector remained compact.  Winds to hurricane force extended out about 30 miles (50 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.  The Hurricane Intensity Index (HII) for Hurricane Hector was 28.3.  The Hurricane Size Index (HSI) was 9,9 and The Hurricane Wind Intensity Size Index (HWISI) was 38.2.

Hurricane Hector will move through an environment capable of supporting a strong hurricane during the next day or two.  It will move over water where the Sea Surface Temperature is near 27°C and 28°C.  Hector will move through an area where the upper level winds are weak and there will be little vertical wind shear.  An eyewall replacement cycle could occur if a rainband wraps around the existing eye and eyewall.  It would cause fluctuations in the intensity of Hurricane Hector.

Hurricane Hector will move south of the subtropical high pressure system over the Eastern North Pacific Ocean.  The high will steer Hurricane Hector toward the west during the next several days.  On its anticipated track Hurricane Hector will be southeast of Hawaii in about three days.

Tropical Storm Ileana developed south of Mexico on Sunday.  The government of Mexico issued a Tropical Storm Watch for the portion of the coast from Lazaro Cardenas to Cabo Corrientes.  At 8:00 p.m. EDT on Sunday the center of Tropical Storm Ileana was located at latitude 13.9°N and longitude 98.9°W which put it about 210 miles (335 km) south-southeast of Acapulco, Mexico.  Ileana was moving toward the west-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 1000 mb.

Tropical Depression Twelve-E formed west of Tropical Storm Ileana on Sunday.  At 5:00 p.m. EDT on Sunday the center of Tropical Depression Twelve-E was located at latitude 14.6°N and longitude 105.8°W which put it about 320 miles (515 km) south-southwest of Manzanillo, Mexico.  It was moving toward the northwest at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1006 mb.

There is uncertainty about the future interaction of Tropical Storm Ileana and Tropical Depression Twelve-E.  The circulation of Tropical Depression Twelve-E is much larger than the circulation of Tropical Storm Ileana.  In addition, upper level divergence form the depression could cause vertical wind shear over Tropical Storm Ileana.  In one possible scenario Tropical Storm Ileana moves toward Tropical Depression Twelve-E and it is absorbed by the larger circulation.  Another possibility is that Tropical Storm Ileana moves around the eastern periphery of the circulation of the tropical depression,  The second scenario would bring Tropical Storm Ileana close to the west coast of Mexico which is why the Tropical Storm Watch was issued.

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.

Hector Strengthens Into a Major Hurricane

Hurricane Hector strengthened to Category 3 on the Saffir-Simpson Scale on Friday night which made it a major hurricane.  At 11:00 p.m. EDT on Friday the center of Hurricane Hector was located at latitude 14.2°N and longitude 130.9°W which put it about 1640 miles (2640 km) east of Hilo, Hawaii.  Hector was moving toward the west at 12 m.p.h. (19 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 140 m.p.h. (225 km/h).  The minimum surface pressure was 967 mb.

Hurricane Hector strengthened on Friday night despite having a double eyewall structure.  There was a small inner eye surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  A clear ring sometimes called a moat surrounded the inner eyewall.  The moat was surrounded by an outer eyewall that consisted of showers and thunderstorms.  Several other bands of showers and thunderstorms were revolving around the concentric eyewalls.  Thunderstorms in the core of Hurricane Hector were generating strong upper level divergence which was pumping mass away from the hurricane in all directions.

The circulation of Hurricane Hector was small.  Winds to hurricane force only extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force only extended out about 70 miles (110 km) from the center.

Hurricane Hector will move through an environment favorable for intensification during the weekend.  Hector will move over water where the Sea Surface Temperature is between 27°C and 28°C.  It will move through an area where the upper level winds are weak.  However, the existence of concentric eyewalls means that an eyewall replacement cycle will occur at some time in the future.  The eyewall replacement will cause Hurricane Hector to weaken when the inner eyewall dissipates and the strongest winds are found in the outer eyewall.  Hector could begin to intensify again if the outer eyewall begins to contract closer to the center of circulation.

Hurricane Hector will move south of the subtropical high pressure system over the Eastern North Pacific Ocean and the high will steer Hector westward during the next few days.  On its anticipated track Hurricane Hector could be southeast of Hawaii in four or five 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.

Hector Rapidly Intensifies Into a Hurricane

Former Tropical Storm Hector rapidly intensified a hurricane on Thursday morning.  At 11:00 a.m. EDT on Thursday the center of Hurricane Hector was located at latitude 14.2°N and longitude 124.6°W which put it about 1135 miles (1825 km) west-southwest of the southern tip of Baja California.  Hector was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 987 mb.

The circulation of Hurricane Hector rapidly became more organized on Thursday morning.  A band of showers and thunderstorms wrapped tightly around the center of circulation.  A small eye appeared on satellite images at the center of Hurricane Hector.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Several other bands of showers and thunderstorms were revolving around the core of the hurricane.  Storms near the core were generating strong upper level divergence which was pumping mass away from the hurricane.  The circulation of Hurricane Hector was relatively small.  Winds to hurricane force extended out about 20 miles (30 km) from the center of circulation.  Winds to tropical storm force extended out about 60 miles (95 km) from the center.

Hurricane Hector will move through an environment favorable for intensification during the next several days.  Hector will move over water where the Sea Surface Temperature is between 27°C and 28°C.  An upper level ridge northeast of Hurricane Hector will produce easterly winds which will blow toward the top of the circulation.  However, the strongest easterly winds will be north of Hector and the vertical wind shear should not be too great over the hurricane.  Hurricane Hector is likely to continue to intensify and it could become a major hurricane.

Hurricane Hector will move south of the subtropical high pressure system over the Eastern North Pacific Ocean.  The subtropical high will steer Hector in a generally westerly direction during the next few days.  On its anticipated track Hurricane Hector will cross into the Central Pacific late in the weekend.  Hector could be southeast of Hawaii early next week.