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Super Typhoon Chaba Threatens Japan and South Korea

Super Typhoon Chaba moved north on Monday and it threatened to bring strong winds and heavy rain to Japan and South Korea.  At 5:00 p.m. EDT on Monday the center of Super Typhoon Chaba was located at latitude 27.5°N and longitude 126.5°E which put it about 100 miles (160 km) west-northwest of Okinawa.  Chaba was moving toward the north at 11 m.p.h. (18 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 925 mb.

Typhoon Chaba is a compact well organized storm.  It has a clear circular eye surrounded by a ring of strong thunderstorms.  Winds to typhoon force extend out about 35 miles (55 km) from the center of circulation.  Additional rainbands are rotating around the core of Typhoon Chaba.  Thunderstorms at the core of Chaba are generating upper level divergence which is pumping mass out in all directions.

The Hurricane Intensity Index (HII) for Typhoon Chaba is 33.3.  The Hurricane Size Index (HSI) is 11.6 and the Hurricane Wind Intensity Size Index (HWISI) is 44.9.  These indices indicate that Typhoon Chaba is stronger, but slightly smaller than Hurricane Matthew which is over the Caribbean Sea.

Although Typhoon Chaba is still in a very favorable environment, it has probably peaked in intensity.  Chaba was the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale earlier today.  Chaba is currently moving over water where the Sea Surface Temperature (SST) is near 29°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Chaba is likely to weaken gradually during the next 24 hours.  In about a day or so, Chaba will move over cooler SSTs.  In addition, when Chaba moves farther north it will move closer to the upper level westerly winds in the middle latitudes.  A combination of cooler SSTs and more vertical wind shear will increase the rate at which Typhoon Chaba will weaken.

Chaba is moving around the western end of a subtropical ridge which is steering the typhoon toward the north.  That general motion is expected to continue for about another 24 hours.  In about a day or so the westerly winds of the middle latitudes are expected to turn Chaba quickly toward the northeast.  On its anticipated track the core of Typhoon Chaba will pass west of the northern Ryukyu Islands.  Chaba could be near Jeju, South Korea and western Kyushu in 24 hours.

Chaba is a very strong typhoon.  Although it will weaken, Typhoon Chaba will bring strong winds and heavy rain to parts of South Korea and Japan.

Powerful Typhoon Chaba Passing South of Okinawa

Powerful Typhoon Chaba is passing south of Okinawa.  At 11:00 p.m. EDT on Sunday the center of Typhoon Chaba was located at latitude 24.5°N and longitude 127.3°E which put it about 180 miles (290 km) south of Okinawa.  Chaba was moving toward the northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 145 m.p.h. (230 km/h) and there were wind gusts to 170 m.p.h. (280 km/h).  The minimum surface pressure was 935 mb.

The circulation of Typhoon Chaba is very well organized.  Chaba has a distinct circular eye surrounded by a ring of strong thunderstorms.  Other rainbands are rotating around the core of the circulation.  The thunderstorms in the core are generating upper level divergence which is pumping out mass to the north of Typhoon Chaba.

Typhoon Chaba is moving through a very favorable environment.  Chaba is moving over water where the Sea Surface Temperature (SST) is near 30°C.  The upper level winds are weak and there is little vertical wind shear.  Typhoon Chaba could intensify a little more during the next 12 to 24 hours.  When Chaba moves farther north, an upper level trough over eastern China will cause more vertical wind shear.  Increased wind shear and cooler SSTs will weaken the typhoon.

Typhoon Chaba is moving around the western end of a subtropical ridge which is steering it toward the northwest.  Chaba will gradually start to move more toward the north.  In about 36 hours the upper level trough over eastern China will begin to steer Typhoon Chaba toward the northeast.  On its anticipated track Typhoon Chaba will move through the Ryukyu Islands southwest of Okinawa during the next 24 hours.  Chaba would be southwest of Kyushu in about 36 hours.

Chaba is a powerful typhoon and it will bring gusty winds and heavy rain to the Ryukyu Islands including Okinawa.

Typhoon Chaba Rapidly Intensifies Into the Equivalent of a Major Hurricane

Typhoon Chaba intensified rapidly into the equivalent of a major hurricane on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Chaba was located at latitude 20.1°N and longitude 131.0°E which put it about 530 miles (855 km) south-southeast of Okinawa.  Chaba was moving toward the northwest at 19 m.p.h. (31 km/h).  The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h).  The minimum surface pressure was 957 mb.

The organization of the circulation of Typhoon Chaba improved significantly on Saturday.  It has a small circular eye which is surrounded by a ring of very strong thunderstorms.  Another primary band of thunderstorms wrapped around the western side of the typhoon.  Thunderstorms in the core of Typhoon Chaba produced strong upper level divergence which pumped out enough mass to allow the pressure at the surface to decrease very rapidly during the past 24 hours.

Typhoon Chaba will continue to move in an environment that is very favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  The upper level winds are weak and there is not much vertical wind shear.  Typhoon Chaba should continue to intensify for another 24 hours and it could reach major typhoon status.

Typhoon Chaba is moving around the western end of a subtropical ridge which is steering the typhoon toward the northwest.  Chaba should start to move more toward the north when it reaches the western end of the ridge.  On its anticipated track Typhoon Chaba could reach Okinawa in about 36 hours.  It will be a powerful typhoon when it moves through the Ryukyu Islands.

Tropical Storm Chaba Organizes and Moves Toward Okinawa

Tropical Storm Chaba strengthened on Thursday as it started to move toward Okinawa.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Chaba was located at latitude 13.8°N and longitude 138.6°E which put it about 1145 miles (1850 km) southeast of Okinawa.  Chaba was moving toward the west at 14 m.p.h. (22 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 996 mb.

The circulation of Tropical Storm Chaba showed signs of better organization on Thursday.  A primary rainband wrapped around the western and south sides of the circulation.  Additional bands of thunderstorms were forming on the southern and eastern side of Tropical Storm Chaba.  Thunderstorms near the core of Chaba were generating upper level divergence which was pumping mass out to the west, south and east of the tropical storm.

Tropical Storm Chaba is moving into an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature (SST) is near 30°C.  An upper level ridge to the north of Chaba is generating easterly winds which are blowing across the northern portion of the tropical storm.  However, those winds are not causing significant vertical wind shear.  The combination of warm SSTs and little vertical wind shear should allow Tropical Storm Chaba to intensify steadily during the next several days.  It could become a typhoon within 24 to 48 hours.  There is a chance that Chaba could become the equivalent of a major hurricane in three or four days.

A subtropical ridge to the north of Chaba is steering the tropical storm toward the west and that general motion is expected to continue in the short term.  When Chaba gets a little closer to the western end of the ridge, it will start to move toward the northwest and when Chaba reaches the western end of the ridge it will turn toward the north.  On it anticipated track Tropical Storm Chaba could be approaching Okinawa and the Ryukyu islands in about three days.  It could be a powerful typhoon at that time.

Typhoon Malakas Turns Toward Japan

Typhoon Malakas made the expected northeast turn toward Japan on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Malakas was located at latitude 27.1°N and longitude 123.8°E which put it about 265 miles (425 km) west of Okinawa.  Malakas was moving toward the northeast at 11 m.p.h. (145 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 structure of Typhoon Malakas is slowly changing as it moves toward the north and encounters a little more wind shear.  Malakas still has an eye, but the thunderstorms around the eyewall are not strong as they were 24 hours ago and a few small breaks may be developing in the eyewall.  There are still a number of rainbands spiraling around the typhoon.  The core of Typhoon Malakas is still generating upper level divergence.  Overall, Malakas is still a well organized, if weaker, typhoon.

Typhoon Malakas has moved around the western end of a subtropical ridge and it has turned toward the northeast.  An upper level trough west of Japan will steer Malakas toward the northeast at a faster speed on Sunday.  On its anticipated track Typhoon Malakas will approach southwestern Kyushu in about 36 hours,  It will bring strong wind and heavy rain to southwestern Japan in about two days.

Strong Typhoon Malakas Turns North Toward Southernmost Ryukyu Islands

Strong Typhoon Malakas made the expected turn toward the north on Friday and it began to move parallel to the east coast of Taiwan toward the southwesternmost Ryukyu Islands.  At 5:00 p.m. EDT on Friday the center of Typhoon Malakas was located at latitude 23.4°N and longitude 123.0°E which put it about 100 miles (160 km) southwest of Ishigaki, Japan.  Malakas was moving toward the north at 10 m.p.h. (16 km/h).  The maximum sustained wind speed was 130 m.p.h. (215 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 937 mb.

Malakas is a strong well organized typhoon.  It has a well formed eye at the center of circulation surrounded by a ring of strong thunderstorms.  Additional bands of thunderstorms are rotating around the core of Malakas and there are more thunderstorms in the southern half of the circulation.  Winds to typhoon force extend out about 35 miles (55 km) in all directions from the center of circulation.  The upper level divergence is strongest to the south of Typhoon Malakas.

Typhoon Malakas is in a very favorable environment.  It is moving over water where the Sea Surface Temperature (SST) is near 29°C.  The upper level winds are not too strong and there is little vertical wind shear.  Typhoon Malakas could intensify a little more during the next 24 hours.  When Typhoon Malakas moves farther north, it will move over cooler SSTs.  In addition there is an upper level trough over eastern China which will cause southwesterly winds and increasing vertical wind shear when Malakas gets farther north.

Typhoon Malakas is moving around the western end of a subtropical ridge and it is likely to continue to move north for another 24 hours or so.  In about a day, the upper level trough over eastern China will start to turn Malakas toward the northeast.  On its anticipated track Typhoon Malakas could approach southwestern Kyushu in about three days.

The center of Typhoon Malakas is passing east of Taiwan.  Some of the rainbands in the western part of the circulation will move over Taiwan, but the core of the typhoon where the strongest wind is occurring will stay east of there.  The center of Malakas will pass west of Ishigaki and Okinawa, but it could move over some of the smaller islands at the very southwestern end of the Ryukyu Islands.  Malakas could cause significant damage on those islands.

Typhoon Malakas Moves Toward Taiwan and the Ryukyu Islands

Typhoon Malakas moved toward Taiwan and the southernmost Ryukyu Islands on Thursday.  At 8:00 p.m. EDT on Thursday the center of Typhoon Malakas was located at latitude 20.1°N and longitude 124.7°W which put it about 285 miles (460 km) south of Ishigaki, Japan.  Malakas was moving toward the northwest at 15 m.p.h. (24 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. (205 km/h).  The minimum surface pressure was 956 mb.

The structure of Typhoon Malakas is well organized.  A small eye has been evident intermittently on satellite imagery.  More of the thunderstorms are forming south of the center of circulation, although there are spiral bands of thunderstorms in all quadrants of the circulation.  The thunderstorms in the core of Typhoon Malakas are generating upper level divergence which is pumping out mass in all directions.  The circulation of Typhoon Malakas has been in a rough equilibrium during the past 24 hours and the intensity has remained relatively steady.

Typhoon Malakas is moving through an environment that is favorable for intensification.  It is moving over water where the Sea Surface Temperature is near 30°C.  Although there is an upper level trough over China and an upper level low to the northeast of Malakas, the upper level winds around the typhoon are relatively light.  There is not much vertical wind shear.  Typhoon Malakas could strengthen further during the next 24 hours.

Typhoon Malakas is moving around the western end of a subtropical ridge.  Malakas turned more toward the northwest on Thursday.  It is expected to move more toward the north on Friday as is reaches the western end of the ridge.  When Malakas moves farther north, the upper level trough over China will steer the typhoon quickly toward the northeast toward the southern end of Kyushu.  On its anticipated track Typhoon Malakas will be near northeastern Taiwan and the southernmost Ryukyu Islands in about 24 hours.

Typhoon Malakas is smaller than Typhoon Meranti was, but Typhoon Malakas is capable of causing significant wind damage.  It will also bring heavy rain.  Since areas on Taiwan received heavy rain when Typhoon Meranti moved past them, it will take less additional rain to create the potential for flash flooding.

Strong Typhoon Meranti Nears Landfall in China

Strong Typhoon Meranti is near a landfall on the east coast of China close to Xiamen.  At 11:00 a.m. EDT on Wednesday the center of Typhoon Meranti was located at latitude 23.9°N and longitude 118.4°E which put it about 40 miles (65 km) south-southeast of Xiamen, China.  Meranti was moving toward the northwest at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h).  The minimum surface pressure was 931 mb.

Meranti has weakened during the past 24 hours, but it remains a strong typhoon.  The Hurricane Intensity Index (HII) for Typhoon Meranti is 29.9.  The Hurricane Size Index (HSI) is 24.5 and the Hurricane Wind Intensity Size Index is 54.4.  These indices suggest that Typhoon Meranti is capable of causing widespread significant damage when it makes landfall.  As a comparison, the HII for Hurricane Ivan just before it made landfall on the Gulf Coast in 2004 was 22.1, the HSI was 34.1 and the HWISI was 56.2.  Thus, Typhoon Meranti is stronger than Hurricane Ivan was, but Meranti is also smaller than Ivan was in 2004.  The HWISI for Typhoon Meranti is close to what it was for Hurricane Ivan.

The center and inner eyewall of Typhoon Meranti moved just south of the southern end of Taiwan.  Since the eyewall stayed over water, it remained intact.  However, the outer concentric eyewall and much of the northern half of the circulation did move across Taiwan.  Flow over the mountains on Taiwan did weaken the northern half of the circulation, while the center and southern half of the circulation remained intact.  Since the core of the circulation stayed over the water, Typhoon Meranti stayed stronger than it would have if the inner eye had moved over Taiwan.

Most of the stronger thunderstorms and heavier rain are near the center of circulation and south of the center.  There are rainbands in other parts of Typhoon Meranti and some of those rainbands are already bringing heavy rain to parts of eastern China.

Typhoon Meranti is moving around the western end of a subtropical ridge which is steering it toward the northwest.  Meranti is expected to turn more toward the north as it move inland over China.  On its anticipated track Typhoon Meranti is expected to move northwest over Fujian province and then turn north toward Nanchang.

Typhoon Meranti is capable of causing significant wind damage over eastern China.  In addtion strong winds will create a significant storm surge along the coast near Xiamen.  Heavy rain will spread inland over Fujian province and the rain could create the potential for flooding over parts of eastern China.

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.

Weakened Tropical Storm Nepartak Still Bringing Rain to Parts of China and Taiwan

Although Tropical Storm Nepartak was weakened significantly during its passage over the mountains on Taiwan, it is still producing heavy rain over portions of eastern China and Taiwan.  At 5:00 p.m. EDT on Friday the center of Tropical Storm Nepartak was located at latitude 24.0°N and longitude 119.0°E which put it about 100 miles (160 km) east-southeast of Xiamen, China.  Nepartak was moving toward the northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 70 m.p.h. (115 km/h) and there were wind gusts to 85 m.p.h. (140 km/h).  The minimum surface pressure was 978 mb.

Typhoon Nepartak brought damaging winds and heavy rainfall to Taiwan when the core of the tropical cyclone passed over that area.  The mountains on Taiwan significantly disrupted the lower levels of the circulation.  There are some indications on satellite imagery that the upper portion of the circulation is located northwest of the surface center.  When a typhoon crosses Taiwan, the mountains can cause the original center of circulation to weaken and a new center can sometimes form over the water on the downstream side of the island.

In any case, crossing over Taiwan caused Nepartak to weaken to a tropical storm and the circulation no longer exhibits a tight inner core.  However, there are still rainbands that are producing heavy rain and wind speeds to almost typhoon force.   Because Nepartak no longer has a tight inner core, it is unlikely to intensify significantly before the centers moves into eastern China.

A ridge northeast of Nepartak is steering the tropical storm toward the northwest and that general motion is expected to continue for the next 12 to 24 hours.  After that time Nepartak is expected to turn toward the north.  On its anticipated track Tropical Storm Nepartak will make landfall in China between Xiamen and Fuqing on Saturday.

Tropical Storm Nepartak could produce locally heavy rainfall over portions of eastern China.  Some of that region has already received a lot of rain from other weather systems.  So, the potential for additional flooding is high in some areas.