Category Archives: Western North Pacific

Western Pacific Typhoons and Tropical Storms

Typhoon In-Fa Passes West of Iwo To

Leave a reply

Typhoon In-Fa passed west of Iwo To on Tuesday night.  At 11:00 p.m. EDT on Tuesday the center of Typhoon In-Fa was located at latitude 24.8°N and longitude 138.4°E which put the center about 185 miles (295 km) west of Iwo To.  In-Fa was moving toward the north at 7 m.p.h. (11 km/h).  The maximum sustained wind speed was 100 m.p.h. (160 km/h) and there were wind gusts to 120 m.p.h. (195 km/h).  The minimum surface pressure was 972 mb.

Typhoon In-Fa maintained its intensity on Tuesday as it passed west of Iwo To.  A circular eye with a diameter of 20 miles (32 km) was at the center of In-Fa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon In-Fa.  Storms near the center of In-Fa generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels was nearly equal to the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure did not change much on Tuesday.

The distribution of wind speeds around Typhoon In-Fa was still relatively symmetrical.  Winds to typhoon force extended out 50 miles (80 km) from the center of In-Fa’s circulation.  Winds to tropical storm force extended out 130 miles (210 km) from the center of Typhoon In-Fa.

The Hurricane Intensity Index (HII) for Typhoon In-Fa is 16.5.  The Hurricane Size Index (HSI) is 16.6 and the Hurricane Wind Intensity Size Index (HWISI) is 33.2. Typhoon In-Fa is similar in intensity to Hurricane Isaias when Isaias hit Florida in 2023.  In-Fa is not as large as Iasais was.

Typhoon In-Fa will move through an environment that will be unfavorable for intensification of a typhoon during the next 24 hours.  In-Fa will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the southern part of an upper level trough that is over Japan.  The upper level trough will produce west-southwesterly winds that will blow toward the top of In-Fa’s circulation.  Those winds will cause the vertical wind shear to increase.  Typhoon In-Fa is likely to weaken gradually during the next 24 hours because of more vertical wind shear.

The upper level trough over Japan will steer Typhoon In-Fa toward the northeast during the next 24 hours.  On its anticipated track, Typhoon In-Fa will pass southeast of Japan.

Typhoon In-Fa will move over cooler Sea Surface Temperatures during the next several days.  The combination of cooler water and more vertical wind shear will cause Typhoon In-Fa to make a transition to a strong extratropical cyclone.

Typhoon In-Fa Stalls Southeast of Iwo To

Leave a reply

Typhoon In-Fa stalled over the Western North Pacific Ocean southeast of Iwo To on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon In-Fa was located at latitude 22.7°N and longitude 144.1°E which put the center about 235 miles (380 km) southeast of Iwo To.  In-Fa was moving toward the east-southeast at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 110 m.p.h. (175 km/h) and there were wind gusts to 130 m.p.h. (210 km/h).  The minimum surface pressure was 965 mb.

Typhoon In-Fa weakened gradually on Saturday while it stalled southeast of Iwo To.  A circular eye with a diameter of 40 miles (65 km) was still present at the center of In-Fa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon In-Fa.  Storms near the center of In-Fa generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels was less than  the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased on Saturday.

The distribution of wind speeds around Typhoon In-Fa was still relatively symmetrical.  Winds to typhoon force extended out 80 miles (130 km) from the center of In-Fa’s circulation.  Winds to tropical storm force extended out 150 miles (240 km) from the center of Typhoon In-Fa.

The Hurricane Intensity Index (HII) for Typhoon In-Fa is 19.2.  The Hurricane Size Index (HSI) is 23.6 and the Hurricane Wind Intensity Size Index (HWISI) is 42.8.  Typhoon In-Fa is similar in size and intensity to Hurricane Gustav when Gustav hit Louisiana in 2008.

Typhoon In-Fa will move through an environment that will be unfavorable for intensification during the next 24 hours.  In-Fa will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the southern part of an upper level trough that is south of Japan.  The upper level trough will produce southwesterly winds that will blow toward the top of In-Fa’s circulation.  Those winds will cause the vertical wind shear to increase.  Typhoon In-Fa is likely to continue to weaken gradually on Sunday because of more vertical wind shear.

A high pressure system that is over the Western North Pacific Ocean southeast of Japan will start to steer Typhoon In-Fa toward the west during the next 24 hours.  On its anticipated track,  Typhoon In-Fa will move south of Iwo To on Sunday.

Typhoon In-Fa Batters Northern Marianas

Leave a reply

Typhoon In-Fa battered Agrihan, Pagan, and Alamagan in the Northern Marianas early on Friday.  At 5:00 a.m. EDT on Friday the center of Typhoon In-Fa was located at latitude 19.1°N and longitude 145.6°E which put the center about 35 miles (55 km) east of Agrihan.  In-Fa was moving toward the northwest at 20 m.p.h. (32 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. (285 km/h).  The minimum surface pressure was 943 mb.

Typhoon In-Fa continued to be in a relatively steady state on Thursday.  A circular eye with a diameter of 40 miles (65 km) was at the center of In-Fa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon In-Fa.  Storms near the center of In-Fa generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels was nearly equal to the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure did not change much on Thursday.

The size of the circulation around Typhoon In-Fa increased on Thursday.  Winds to typhoon force extended out 80 miles (130 km) from the center of In-Fa’s circulation.  Winds to tropical storm force extended out 175 miles (285 km) from the center of Typhoon In-Fa.

The Hurricane Intensity Index (HII) for Typhoon In-Fa is 29.9.  The Hurricane Size Index (HSI) is 24.5 and the Hurricane Wind Intensity Size Index (HWISI) is 54.4. Typhoon In-Fa is similar in size and intensity to Hurricane Helen when Helene hit Florida in 2024.

Typhoon In-Fa will move through an environment that will be favorable for a strong typhoon during the next 24 hours.  In-Fa will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon In-Fa appears to be in a near equilibrium with its environment.  In-Fa is likely to maintain its intensity during the next 24 hours.

Typhoon In-Fa will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer In-Fa toward the northwest during the next 24 hours.  On its anticipated track, Typhoon In-Fa will move away from Alamagan, Pagan, and Agrihan on Friday.

Typhoon In-Fa will continue to bring strong winds and heavy rain to Agrihan, Pagan, and Alamagan until it moves farther to the northwest.  Heavy rain is likely to cause flash floods in some locations.

Typhoon In-Fa Moves Toward Northern Marianas

Leave a reply

Typhoon In-Fa continued to move toward the Northern Marianas on Wednesday.  At 11:00 p.m. EDT on Wednesday the center of Typhoon In-Fa was located at latitude 16.1°N and longitude 153.8°E which put the center about 565 miles (910 km) east of Saipan.  In-Fa was moving toward the west-northwest at 18 m.p.h. (30 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 951 mb.

Typhoon In-Fa did not change much on Wednesday.  A circular eye with a diameter of 40 miles (65 km) was at the center of In-Fa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon In-Fa.  Storms near the center of In-Fa generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels was nearly equal to the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure did not change much on Wednesday.

The distribution of wind speeds in Typhoon In-Fa was very symmetrical.  Winds to typhoon force extended out 50 miles (80 km) from the center of In-Fa’s circulation.  Winds to tropical storm force extended out 125 miles (200 km) from the center of Typhoon In-Fa.

The Hurricane Intensity Index (HII) for Typhoon In-Fa is 25.1.  The Hurricane Size Index (HSI) is 18.1 and the Hurricane Wind Intensity Size Index (HWISI) is 43.2.  Typhoon In-Fa is similar in size to Hurricane Ian when Ian hit Southwest Florida in 2022.  In-Fa is not as strong as Ian was.

Typhoon In-Fa will move through an environment that will be favorable for a strong typhoon during the next 24 hours.  In-Fa will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon In-Fa appears to be in a near equilibrium with its environment.  In-Fa is likely to maintain its intensity during the next 24 hours.

Typhoon In-Fa will move around the southern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer In-Fa toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon In-Fa will approach Alamagan, Pagan, and Agrihan in 24 hours.

Typhoon In-Fa will be the equivalent of a major hurricane when it reaches Alamagan, Pagan, and Agrihan.  In-Fa will bring strong winds and heavy rain to those islands.  Heavy rain is likely to cause flash floods.

Typhoon In-Fa Churns Westward

Leave a reply

Typhoon In-Fa continued to churn westward over the Western North Pacific Ocean east of the Northern Marianas on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Typhoon In-Fa was located at latitude 15.0°N and longitude 159.3°E which put the center about 940 miles (1515 km) east of Saipan.  In-Fa was moving toward the west-northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 140 m.p.h. (225 km/h) and there were wind gusts to 165 m.p.h. (265 km/h).  The minimum surface pressure was 945 mb.

An eyewall replacement cycle occurred in the core of Typhoon In-Fa on Tuesday.  The original eye and eyewall disappeared by Tuesday evening.  A new eye with a diameter of 40 miles (65 km) was at the center of In-Fa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon In-Fa.  Storms near the center of In-Fa generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels was nearly equal to the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure did not change much on Tuesday.

The distribution of wind speeds in Typhoon In-Fa was very symmetrical.  Winds to typhoon force extended out 45 miles (75 km) from the center of In-Fa’s circulation.  Winds to tropical storm force extended out 105 miles (165 km) from the center of Typhoon In-Fa.

The Hurricane Intensity Index (HII) for Typhoon In-Fa is 28.3.  The Hurricane Size Index (HSI) is 17.1 and the Hurricane Wind Intensity Size Index (HWISI) is 45.4. Typhoon In-Fa is similar in size to Hurricane Ian when Ian hit Southwest Florida in 2022.  In-Fa is not quite as strong as Ian was.

Typhoon In-Fa will move through an environment that will be favorable for intensification during the next 24 hours.  In-Fa will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon In-Fa could intensify during the next 24 hours unless another eyewall replacement cycle occurs.

Typhoon In-Fa will move around the southern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer In-Fa toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon In-Fa will continue to move toward the Northern Marianas.

Typhoon In-Fa Rapidly Intensifies to Equivalent of a Major Hurricane

Leave a reply

Typhoon In-Fa rapidly intensified to the equivalent of a major hurricane on Monday over the Western North Pacific Ocean east of the Northern Marianas.  At 11:00 a.m. EDT on Monday the center of Typhoon In-Fa was located at latitude 14.1°N and longitude 162.6°E which put the center about 1135 miles (1830 km) east of Saipan.  In-Fa was moving toward the west-northwest at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 946 mb.

Typhoon In-Fa rapidly intensified to the equivalent of a major hurricane on Monday.  A small circular eye with a diameter of 8 miles (13 km) formed at the center of In-Fa’s circulation.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the center of Typhoon In-Fa.  Storms near the center of In-Fa generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon In-Fa was small.  Winds to typhoon force extended out 30 miles (50 km) from the center of In-Fa’s circulation.  Winds to tropical storm force extended out 80 miles (130 km) from the center of Typhoon In-Fa.

The Hurricane Intensity Index (HII) for Typhoon In-Fa is 25.1.  The Hurricane Size Index (HSI) is 9.6 and the Hurricane Wind Intensity Size Index (HWISI) is 34.7.  Typhoon In-Fa is similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Typhoon In-Fa will move through an environment that will be favorable for intensification during the next 24 hours.  In-Fa will move over water where the Sea Surface Temperatures are near 29°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Typhoon In-Fa could continue to intensify during the next 24 hours unless the inner end of a rainband wraps around the existing eye and eyewall.  If concentric eyewalls form, then an eyewall replacement cycle could cause In-Fa to weaken.

Typhoon In-Fa will move around the southern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer In-Fa toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon In-Fa will move toward the Northern Marianas.

 

In-Fa Strengthens to a Typhoon

Leave a reply

Former Tropical Storm In-Fa strengthened to a typhoon on Sunday as it moved over the Western North Pacific Ocean northwest of Kwajalein.  At 5:00 p.m. EDT on Sunday the center of Typhoon In-Fa was located at latitude 13.6°N and longitude 163.7°E which put the center about 420 miles (675 km) northwest of Kwajalein.  In-Fa was moving toward the northwest at 9 m.p.h. (15 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 979 mb.

Former Tropical Storm In-Fa strengthened to a typhoon on Sunday.  The inner end of a rainband wrapped around the center of In-Fa’s circulation.  Bands of showers and thunderstorms were revolving around the center of Typhoon In-Fa.  Storms near the center of In-Fa generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon In-Fa was small.  Winds to typhoon force extended out 20 miles (30 km) from the center of Typhoon In-Fa.  Winds to tropical storm force extended out 80 miles (130 km) from the center of Typhoon In-Fa.

Typhoon In-Fa will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  In-Fa will move over water where the Sea Surface Temperatures are near 29°C.  It will move under the southern part of an upper level trough that is over the Western North Pacific Ocean.  The upper level trough will produce westerly winds that will blow toward the top of In-Fa’s circulation.  Those winds will cause moderate vertical wind shear.  The moderate vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification.  Typhoon In-Fa could intensify during the next 24 hours.  In-Fa could strengthen to the equivalent of a major hurricane during the next several days.

Typhoon In-Fa will move around the southern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer In-Fa toward the northwest during the next 24 hours.  On its anticipated track, Typhoon In-Fa will move farther away from Kwajalein.

Typhoon Champi Brings Wind and Rain to Southern Ryukyu Islands

Leave a reply

Typhoon Champi brought wind and rain to the southern Ryukyu Islands and to northeastern Taiwan on Friday.  At 11:00 a.m. EDT on Friday the center of Typhoon Champi was located at latitude 25.3°N and longitude 122.6°E which put the center about 75 miles (120 km) east of Taipei, Taiwan.  Champi was moving toward the north-northwest at 16 m.p.h. (16 km/h).  The maximum sustained wind speed was 115 m.p.h. (185 km/h) and there were wind gusts to 145 m.p.h. (235 km/h).  The minimum surface pressure was 949 mb.

A weather station on Ishigakijima Island reported a sustained wind speed of 78 m.p.h. (125 km/h).  The weather station also reported 4.94 inches (154.0 mm) of rain.

A weather station in Ohara, Japan reported a sustained wind speed of 75 m.p.h. (121 km/h).

A weather station on Yonagunijima Island reported a sustained wind speed of 66 m.p.h. (107 km/h).  The weather station also reported 8.33 inches (211.5 mm) of rain.

Typhoon Champi was the equivalent of a major hurricane on Friday morning.  Winds to typhoon force extended out 85 miles (135 km) from the center of Champi’s circulation.  Winds to tropical storm force extended out 250 miles (400 km) from the center of Typhoon Champi.

The Hurricane Intensity Index (HII) for Typhoon Champi was 20.6.  The Hurricane Size Index (HSI) was 31.8 and the Hurricane Wind Intensity Size Index (HWISI) was 52.4.  Typhoon Champi was similar in intensity to Hurricane Irma when Irma hit south Florida in 2017.  Champi is larger than Irma was.

Typhoon Champi will move around the western end of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Champi toward the north during the next 24 hours.  On its anticipated track, Typhoon Champi will remain east of China.

Typhoon Champi will move through an environment that will be unfavorable for intensification during the next 24 hours.  Champi will move over water where the Sea Surface Temperatures are near 26°C.  It will move under the eastern side of an upper level trough that is near the east coast of China.  The upper level trough will produce strong southwesterly winds that will blow toward the top of Champi’s circulation.  Those winds will cause strong vertical wind shear.  Champi will also continue to move through a mass of drier air.  Typhoon Champi is likely to weaken steadily during the next 24 hours because of the effects of strong vertical wind shear and drier air.

Elsewhere over the Western North Pacific Ocean, Tropical Depression 30W formed northwest of Kwajalein.  At 11:00 a.m. EDT on Friday the center of Tropical Depression 30W was located at latitude 10.9°N and longitude 166.3°E which put the center about 185 miles (300 km) northwest of Kwajalein.  The tropical depression moving toward the northwest at 2 m.p.h. (3 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 1004 mb.

Typhoon Champi Approaches Southern Ryukyu Islands

Leave a reply

Typhoon Champi was approaching the southern Ryukyu Islands on Wednesday evening.  At 11:00 p.m. EDT on Wednesday the center of Typhoon Champi was located at latitude 20.6°N and longitude 125.7°E which put the center about 295 miles (475 km) south-southeast of Ishigakijima, Japan.  Champi was moving toward the west-northwest at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 160 m.p.h. (260 km/h).  The minimum surface pressure was 940 mb.

Typhoon Champi weakened on Wednesday.  Even though Champi weakened, it was still a very well organized typhoon.  A circular eye with a diameter of 35 miles (55 km) was at the center of Champi’s circulation.  Bands of showers and thunderstorms were revolving around the the center of Typhoon Champi.  Storms near the center of Champi generated upper level divergence that pumped mass away from the typhoon.  The removal of mass in the upper levels was less than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure increased on Wednesday.

The circulation around Typhoon Champi was large.  Winds to typhoon force extended out 100 miles (160 km) from the center of Champi’s circulation.  Winds to tropical storm force extended out 345 miles (555 km) from the center of Typhoon Champi.

The Hurricane Intensity Index (HII) for Typhoon Champi is 25.1.  The Hurricane Size Index (HSI) is 34.2 and the Hurricane Wind Intensity Size Index (HWISI) is 59.3.  Typhoon Champi is similar in size to Hurricane Ivan when Ivan hit the northern Gulf Coast in 2004.  Champi is stronger than Ivan was.

Typhoon Champi will move through an environment that will be unfavorable for intensification during the next 24 hours.  Champi will move over water where the Sea Surface Temperatures are near 28°C.  It will move under the eastern side of an upper level trough that is near the east coast of China.  The upper level trough will produce southwesterly winds that will blow toward the top of Champi’s circulation.  Those winds will cause the vertical wind shear to increase.   Champi will also move into a region of drier air on Thursday.  Typhoon Champi is likely to weaken during the next 24 hours because of more vertical wind shear and drier air.

Typhoon Champi will move around the western part of a high pressure system that is over the Western North Pacific Ocean. The high pressure system will steer Champi toward the north-northwest during the next 24 hours.  On its anticipated track, the center of Typhoon Champi will be near Ishigakijima in 24 hours.

Typhoon Champi will bring strong winds and heavy rain to the southern Ryukyu Islands.  Heavy rain is likely to cause flash floods in some locations.

Typhoon Champi could also bring strong winds and heavy rain to parts of Taiwan.

Intense Typhoon Champi Churns West

Intense Typhoon Champi churned westward over the Western North Pacific Ocean on Tuesday.  At 5:00 p.m. EDT on Tuesday the center of Typhoon Champi was located at latitude 17.7°N and longitude 130.9°E which put the center about 670 miles (1080 km) south-southeast of Okinawa.  Champi was moving toward the west-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 185 m.p.h. (295 km/h) and there were wind gusts to 225 m.p.h. (360 km/h).  The minimum surface pressure was 895 mb.

Intense Typhoon Champi got even stronger on Tuesday.  A circular eye with a diameter of 35 miles (55 km) was at the center of Champi’s circulation.  Bands of showers and thunderstorms were revolving around the the center of Typhoon Champi.  Storms near the center of Champi generated upper level divergence that pumped mass away from the typhoon.  The removal of mass caused the surface pressure to decrease.

The circulation around Typhoon Champi was large.  Winds to typhoon force extended out 100 miles (160 km) from the center of Champi’s circulation.  Winds to tropical storm force extended out 290 miles (465 km) from the center of Typhoon Champi.

The Hurricane Intensity Index (HII) for Typhoon Champi is 44.1.  The Hurricane Size Index (HSI) is 30.4 and the Hurricane Wind Intensity Size Index (HWISI) is 74.5.  Typhoon Champi is similar in intensity to Hurricane Dorian when Dorian hit the Bahamas in 2019.  Champi is much larger than Dorian was.

Typhoon Champi will move through an environment that will be favorable for an intense typhoon during the next 24 hours.  Champi will move over water where the Sea Surface Temperatures are 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 Champi could maintain its intensity during the next 24 hours unless the inner end of a rainband wraps around the existing eye and eyewall.  If concentric eyewalls form, then an eyewall replacement cycle would cause Champi to weaken.

Typhoon Champi will move around the southwestern part of a high pressure system that is over the Western North Pacific Ocean.  The high pressure system will steer Champi toward the west-northwest during the next 24 hours.  On its anticipated track, Typhoon Champi will continue to move toward Taiwan and the southern Ryukyu Islands.  Champi could approach the southern Ryukyu Islands in 48 hours.