Typhoon Champi Brings Wind and Rain to Guam

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Typhoon Champi brought wind and rain to Guam on Saturday.  At 5:00 p.m. EDT on Saturday the center of Typhoon Champi was located at latitude 13.2°N and longitude 144.3°E which put the center about 40 miles (65 km) south of Guam.  Champi was moving toward the west-northwest at 16 m.p.h. (26 km/h).  The maximum sustained wind speed was 150 m.p.h. (240 km/h) and there were wind gusts to 185 m.p.h. (295 km/h).  The minimum surface pressure was 934 mb.

Typhoon Warnings are in effect for Guam and Rota,

Tropical Storm Warnings are in effect for Tinian and Saipan.

The core of Typhoon Champi where the strongest winds are occurring passed just to the south of Guam on Saturday.  Bands in the northern side of Champi’s circulation brought strong winds and rain to Guam, Rota, Tinian and Saipan.

A weather station at the Guam International Airport (PGUM) reported a sustained wind speed of 47 m.p.h. (76 km/h) and a wind gust of 72 m.p.h. (116 km/h).

A weather station at Andersen Air Force Base (PGUA) reported a sustained wind speed 0f 46 m.p.h. (74 km/h) and a wind gust of 59 m.p.h. (95 km/h).

Typhoon Champi was the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale.  Winds to typhoon force extended out 60 miles (95 km) from the center of Champi’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Typhoon Champi.

The Hurricane Intensity Index (HII) for Typhoon Champi is 31.6.  The Hurricane Size Index (HSI) is 18.6 and the Hurricane Wind Intensity Size Index (HWISI) is 50.2.  Typhoon Champi is similar in size and intensity to Hurricane Laura when Laura hit Southwest Louisiana in 2020.

Typhoon Champi will move around the southern side 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 move away from Guam on Sunday.

Typhoon Champi will move through an environment that will be favorable 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 southern part of an upper level ridge that is over the Western North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Champi’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Typhoon Champi could intensify during the next 24 hours unless the inner end of a rainband wraps around the existing eye and eyewall.  If concentric eyewalls form and an eyewall replacement cycle occurs, Champi will weaken, at least temporarily.

Hurricane Trudy Moves Closer to Mexico

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Hurricane Trudy moved closer to the west coast of Mexico on Saturday.  At 5:00 p.m. EDT on Saturday the center of Hurricane Trudy was located at latitude 17.5°N and longitude 105.0°W which put the center about 115 miles (185 km) south-southwest of Manzanillo, Mexico.  Trudy was moving toward the northwest at 10 m.p.h. (16 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 976 mb.

A Hurricane Warning is in effect for the portion of the coast from Manzanillo to Cabo Corrientes, Mexico.

A Hurricane Watch is in effect for the portion of the coast from Manzanillo to Punta San Telmo, Mexico.

A Tropical Storm Warning is in effect for the portion of the coast from Manzanillo to Lazaro Cardenas, Mexico.

A Tropical Storm Warning is in effect for the portion of the coast from Cabo Corrientes to San Blas, Mexico.

A Tropical Storm Warning is in effect for Las Islas Marias.

Hurricane Trudy appeared to go through an eyewall replacement cycle during the past 24 hours.

A circular eye with a diameter of 45 miles (75 km) was at the center of Trudy’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 core of Trudy’s circulation.  Storms near the core of Trudy generated upper level divergence that pumped mass away from the hurricane.  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 in Hurricane Trudy was fairly symmetrical.  Winds to hurricane force extended out 35 miles (55 km) from the center of Trudy’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Hurricane Trudy.

The Hurricane Intensity Index (HII) for Hurricane Trudy is 16.5.  The Hurricane Size Index (HSI) is 12.6 and the Hurricane Wind Intensity Size Index (HWISI) is 29.1.  Hurricane Trudy is similar in intensity to Hurricane Idalia when Idalia hit Florida in 2023.  Trudy is larger than Isaias was.

Hurricane Trudy will move through an environment that will be somewhat favorable for intensification during the next 24 hours.  Trudy will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the southeastern part of an upper level trough that is near Baja California.  The upper level trough will produce westerly winds that will blow toward the top of Trudy’s circulation.  Those winds will cause the vertical wind shear to increase.  Hurricane Trudy could intensify on Sunday if the vertical wind shear does not increase too much.

Hurricane Trudy will move around the western side of a high pressure system that is over Mexico.  The high pressure system will steer Trudy toward the northwest during the next 24 hours.  On its anticipated track, the center of Hurricane Trudy will approach the west coast of Mexico between Manzanillo and Cabo Corrientes.

The center of Hurricane Trudy is forecast to remain west of Mexico.  However, bands in the eastern side of Trudy’s circulation will bring strong winds and heavy rain to the west coast of Mexico between Manzanillo and Cabo Corrientes.  Heavy rain is likely to cause flash floods in some locations.

Tropical Cyclone Wati Forms over South Pacific

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Tropical Cyclone Wati formed over the South Pacific Ocean east of Samoa on Friday night.  At 5:00 a.m. EDT on Saturday the center of Tropical Cyclone Wati was located at latitude 13.6°S and longitude 163.1°W which put the center about 510 miles (820 km) east of Pago Pago, Samoa.  Wati was moving toward the south-southeast at 14 m.p.h. (22 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 986 mb.

A low pressure system over the South Pacific Ocean east of Samoa strengthened on Saturday night and the Fiji Meteorological Service designated the system as Tropical Cyclone Wati.

Thunderstorms were occurring near the center of Tropical Cyclone Wati.  Bands of showers and thunderstorms were revolving around the center of Wati’s circulation.  Storms near the center of Wati generated upper level divergence that pumped mass away from the tropical cyclone.  The removal of mass caused the surface pressure to decrease.

Winds to tropical storm force extended out 100 miles (160 km) from the center of Tropical Cyclone Wati.

Tropical Cyclone Wati will move through an environment that will be favorable for intensification during the next 24 hours.  Wati will move over water where the Sea Surface Temperatures are near 27°C.  It will move under the western part of an upper level ridge that is over the South Pacific Ocean.  The upper level ridge will produce northerly winds that will blow toward the top of Wati’s circulation.  Those winds will cause moderate vertical wind shear.  The vertical wind shear will inhibit intensification, but wind shear will not be enough to prevent intensification.  Tropical Cyclone Wati will intensify during the next 24 hours.  Wati is likely to strengthen to the equivalent of a hurricane/typhoon.

Tropical Cyclone Wati will move around the western end of a high pressure system that is over the South Pacific Ocean.  The high pressure system will steer Wati toward the south-southeast during the next 24 hours.  On its anticipated track, Tropical Cyclone Wati will move farther away form Samoa.  Wati will move over Aitutaki on Sunday.

Tropical Cyclone Wati will bring strong winds and heavy rain to Aitutaki.  Heavy rain is likely to cause flash floods.

 

Typhoon Champi Rapidly Intensified to Equivalent of Major Hurricane

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Typhoon Champi rapidly intensified to the equivalent of a major hurricane as it moved closer to Guam on Friday night.  At 5:00 a.m. EDT on Saturday the center of Typhoon Champi was located at latitude 12.6°N and longitude 146.7°E which put the center about 180 miles (295 km) east-southeast of Guam.  Champi was moving toward the west at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 130 m.p.h. (210 km/h) and there were wind gusts to 155 m.p.h. (250 km/h).  The minimum surface pressure was 948 mb.

Typhoon Warnings are in effect for Guam and Rota,

Tropical Storm Warnings are in effect for Tinian and Saipan.

Typhoon Champi rapidly intensified to the equivalent of a major hurricane on Friday night.  A small circular eye with a diameter of 6 miles (10 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 distribution of wind speed became more symmetrical when Typhoon Champi rapidly intensified.  Winds to typhoon force extended out 60 miles (95 km) from the center of Champi’s circulation.  Winds to tropical storm force extended out 130 miles (210 km) from the center of Typhoon Champi.

The Hurricane Intensity Index (HII) for Typhoon Champi is 25.1.  The Hurricane Size Index (HSI) is 18.5 and the Hurricane Wind Intensity Size Index (HWISI) is 43.6.  Typhoon Champi is similar in intensity to Hurricane Harvey when Harvey hit Texas in 2017.  Champi is bigger than Harvey was.

Typhoon Champi will move through an environment that will be favorable 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 southern part of an upper level ridge that is over the Western North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Champi’s circulation.  Those winds will cause some vertical wind shear. The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Typhoon Champi will intensify during the next 24 hours.  Champi could strengthen to the equivalent of a Category 5 hurricane on Saturday.

Typhoon Champi will move around the southern side 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 reach Guam in less than 12 hours.

Typhoon Champi is could be the equivalent of a Category 5 hurricane when it reaches Guam.  Champi will bring strong winds and heavy rain to Guam, Rota, Tinian and Saipan.  The strongest winds and heaviest rain are likely to affect Guam and Rota.  Typhoon Champi will be capable of causing severe damage in Guam.  Heavy rain is likely to cause flash floods in some locations.

Flood Watches are in effect for Guam, Rota, Tinian and Saipan.

Champi Strengthens to a Typhoon East of Guam

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Former Tropical Storm Champi strengthened to a typhoon east of Guam on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Champi was located at latitude 12.0°N and longitude 149.6°E which put the center about 375 miles (610 km) east-southeast of Guam.  Champi was moving toward the west-northwest at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 85 m.p.h. (135 km/h) and there were wind gusts to 105 m.p.h. (165 km/h).  The minimum surface pressure was 984 mb.

Typhoon Warnings are in effect for Guam and Rota,

Tropical Storm Warnings are in effect for Tinian and Saipan.

Former Tropical Storm Champi strengthened to a typhoon on Friday.  The inner end of a rainband wrapped around the center of Typhoon Champi.  A small circular eye formed 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 strongest winds were occurring in the northern side of Typhoon Champi.  Winds to typhoon force extended out 30 miles (50 km) in the northern half of Champi’s circulation.  Winds to tropical storm extended out 100 miles (160 km) from the center of Typhoon Champi.

Typhoon Champi will move through an environment that will be favorable 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 southern part of an upper level ridge that is over the Western North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Champi’s circulation.  Those winds will cause some vertical wind shear. The vertical wind shear will inhibit intensification, but the wind shear will not be enough to prevent intensification.  Typhoon Champi will intensify during the next 24 hours.  Champi could strengthen to the equivalent of a major hurricane on Saturday.

Typhoon Champi will move around the southern side 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 reach Guam in 24 hours.

Typhoon Champi is could be the equivalent of a major hurricane when it reaches Guam.  Champi is likely to bring strong winds and heavy rain to Guam, Rota, Tinian and Saipan.  The strongest winds and heaviest rain are likely to affect Guam and Rota.  Heavy rain is likely to cause flash floods in some locations.

Flood Watches are in effect for Guam, Rota, Tinian and Saipan.

Trudy Intensifies to a Major Hurricane

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Hurricane Trudy intensified to a major hurricane on Thursday night as it moved over the Eastern North Pacific Ocean south of Mexico.  At 8:00 a.m. EDT on Friday the center of Hurricane Trudy was located at latitude 14.5°N and longitude 102.5°W which put the center about 240 miles (385 km) southwest of Acapulco, Mexico.  Trudy was moving toward the northwest at 6 m.p.h. (15 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 956 mb.

A Hurricane Watch is in effect for the portion of the coast from Punta San Telmo to Cabo Corrientes, Mexico.

A Tropical Storm Warning is in effect for the portion of the coast from Manzanillo to Zihuatanejo, Mexico.

Hurricane Trudy intensified to a major hurricane on Thursday night.

A circular eye with a diameter of 17 miles (28 km) was at the center of Hurricane Trudy.  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 core of Trudy’s circulation.  Storms near the core of Trudy generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

Winds to hurricane force extended out 30 miles (50 km) from the center of Hurricane Trudy.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Trudy’ circulation.

The Hurricane Intensity Index (HII) for Hurricane Trudy is 22.1.  The Hurricane Size Index (HSI) is 20.3 and the Hurricane Wind Intensity Size Index (HWISI) is 42.4.  Hurricane Trudy is similar in intensity to Hurricane Milton when Milton hit Florida in 2024.  Trudy is not quite as large as Milton was.

Hurricane Trudy will move through an environment that will be favorable for intensification during the next 24 hours.  Trudy will move over water where the Sea Surface Temperatures are near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Trudy will intensify during the next 24 hours.

Hurricane Trudy will move around the western side of a high pressure system that is over Mexico.  The high pressure system will steer Trudy toward the northwest during the next 24 hours.  On its anticipated track, Hurricane Trudy will move closer to the coast of southwestern Mexico.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Simon was weakening south of Baja California.  At 5:00 a.m. EDT on Friday the center of Tropical Storm Simon was located at latitude 20.0°N and longitude 108.8°W which put the center about 210 miles (335 km) south-southeast of Cabo San Lucas, Mexico.  Simon was moving toward the northwest at 9 m.p.h. (15 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 1002 mb.

Tropical Storm Champi Forms east of Guam

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Tropical Storm Champi formed over the Western North Pacific Ocean east of Guam on Thursday.  At 5:00 p.m. EDT on Thursday the center of Tropical Storm Champi was located at latitude 11.6°N and longitude 155.8°E which put the center about 795 miles (1285 km) east of Guam.  Champi was moving toward the west-northwest 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 999 mb.

Typhoon Watches are in effect for Guam, Rota, Tinian, and Saipan.

A low pressure system over the Western North Pacific Ocean east of Guam strengthened on Thursday and the Japan Meteorological Agency designated the system as Tropical Storm Champi.

Even though Tropical Storm Champi was strengthening on Thursday, the distribution of thunderstorms in Champi was asymmetrical.  Thunderstorms were occurring in bands in the western and southern parts of Champi’s circulation.  Bands in the eastern and southern parts of Tropical Storm Champi consisted primarily of showers and lower clouds.  Storms near the center of Champi began to generate upper level divergence that pumped mass away to the west of the tropical storm.  The removal of mass caused the surface pressure to start to decrease.

The distribution of wind speeds in Tropical Storm Champi was also asymmetrical.  Winds to tropical storm force extended out 85 miles (135 km) in the southern half of Champi’s circulation.  The winds in the northern part of Tropical Storm Champi were blowing at less than tropical storm force.

Tropical Storm Champi will move through an environment that will be favorable 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 southern part of an upper level ridge that is over the Western North Pacific Ocean.  The upper level ridge will produce easterly winds that will blow toward the top of Champi’s circulation.  Those winds will cause some vertical wind shear.  The vertical wind shear will inhibit intensiciation, but the wind shear will not be enough to prevent intensification.  Tropical Storm Champi will intensify during the next 24 hours.  Champi could strengthen to a typhoon by Friday night.

Tropical Storm Champi will move around the southern side 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, Tropical Storm Champi will move toward the Marianas.  Champi could reach the Marianas in 48 hours.

Tropical Storm Champi is likely to be a typhoon when it reaches the Marianas.  Champi is likely to bring strong winds and heavy rain to Guam, Rota, Tinian and Saipan.  Heavy rain is likely to cause flash floods in some locations.

Trudy Strengthens to a Hurricane

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Former Tropical Storm Trudy strengthened to a hurricane on Wednesday night as it moved over the Eastern North Pacific Ocean south of Mexico.  At 5:00 a.m. EDT on Thursday the center of Hurricane Trudy was located at latitude 12.9°N and longitude 101.6°W which put the center about 300 miles (480 km) south-southwest of Acapulco, Mexico.  Trudy was moving toward the northwest at 9 m.p.h. (15 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 989 mb.

Former Tropical Storm Trudy strengthened to a hurricane on Wednesday night.

Tall thunderstorms were occurring near the center of Hurricane Trudy.  Thunderstorms were also occurring in bands revolving around the center of Trudy’s circulation.  Storms near the center of Trudy generated upper level divergence that pumped mass away from the hurricane.  The removal of mass caused the surface pressure to decrease.

The strongest winds were occurring in the northern side of Hurricane Trudy.  Winds to hurricane force extended out 25 miles (40 km) in the northern side of Trudy’s circulation.  Winds to tropical storm force extended out 115 miles (185 km) from the center of Hurricane Trudy.

Hurricane Trudy will move through an environment that will be favorable for intensification during the next 24 hours.  Trudy will move over water where the Sea Surface Temperatures are near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Hurricane Trudy will intensify during the next 24 hours.  Trudy could rapidly intensify to a major hurricane by early on Friday.

Hurricane Trudy will move around the western side of a high pressure system that is over Mexico.  The high pressure system will steer Trudy toward the west-northwest during the next 24 hours.  On its anticipated track, Hurricane Trudy will move closer to the coast of southwestern Mexico.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Simon was still meandering west of Mexico.  At 5:00 a.m. EDT on Thursday the center of Tropical Storm Simon was located at latitude 19.2°N and longitude 108.5°W which put the center about 200 miles (320 km) west-southwest of Cabo Corrientes, Mexico.  Simon was stationary.  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 996 mb.

Hurricane Simon Meanders West of Mexico

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Hurricane Simon meandered over the Eastern North Pacific Ocean west of Mexico on Tuesday.  At 11:00 p.m. EDT on Tuesday the center of Hurricane Simon was located at latitude 20.1°N and longitude 107.6°W which put the center about 125 miles (200 km) west of Cabo Corrientes, Mexico.  Simon was moving toward the west at 2 m.p.h. (3 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.

A Hurricane Watch is in effect for Las Islas Marias.

Hurricane Simon strengthened on Tuesday evening as it meandered just to the west of Mexico.

A very small circular eye with a diameter of 6 miles (10 km) was at the center of Hurricane Simon.  The eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms.  Short bands of showers and thunderstorms were revolving around the core of Simon’s circulation.  Storms near the core of Simon generated upper level divergence that pumped mass away from the hurricane.  The removal of mass in the upper levels was greater than the convergence of mass in the lower levels of the atmosphere.  So, the surface pressure decreased on Tuesday evening.

The circulation around Hurricane Simon was very small.  Winds to hurricane force extended out 15 miles (25 km) from the center of Simon’s circulation.  Winds to tropical storm force extended out 35 miles (55 km) from the center of Hurricane Simon.

The Hurricane Intensity Index (HII) for Hurricane Simon is 19.2.  The Hurricane Size Index (HSI) is 4.7 and the Hurricane Wind Intensity Size Index (HWISI) is 23.9.  Hurricane Simon is similar in intensity to Hurricane Zeta when Zeta hit Louisiana in 2020.  Simon is much smaller than Zeta was.

Hurricane Simon will move through an environment favorable for intensification during the next 12 hours.  Simon will move over water where the Sea Surface Temperatures are near 30°C.  It will move under the middle of an upper level ridge that is over Mexico and the Eastern North Pacific Ocean.  The upper level winds are weak near the middle of the ridge and there will be little vertical wind shear.  Hurricane Simon could intensify back to a major hurricane during the next 12 hours.  Simon could meander back over cooler water it has mixed to the surface later on Wednesday.  If Simon meanders over that cooler water, then it is likely to weaken, because it will extract less energy from the ocean.

Hurricane Simon will be in an area where the steering winds are weak during the next 24 hours.  On its anticipated track, Hurricane Simon will continue to meander slowly west of Mexico on Wednesday.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Trudy formed south of Mexico.

At 11:00 p.m. EDT on Tuesday the center of Tropical Storm Trudy was located at latitude 20.1°N and longitude 107.6°W which put the center about 440 miles (705 km) south-southeast of Acapulco, Mexico.  Trudy was moving toward the northwest at 10 m.p.h. 165 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 1004 mb.

Typhoon Koguma Continues to Weaken

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Typhoon Koguma continued to weaken on Monday as it moved over the Western North Pacific Ocean east of Japan.  At 11:00 p.m. EDT on Monday the center of Typhoon Koguma was located at latitude 34.6°N and longitude 152.6°E which put the center about 690 miles (1110 km) east of Tokyo, Japan.  Koguma was moving toward the northeast at 28 m.p.h. (45 km/h).  The maximum sustained wind speed was 80 m.p.h. (130 km/h) and there were wind gusts to 100 m.p.h. (160 km/h).  The minimum surface pressure was 979 mb.

Typhoon Koguma started to make a transition to a strong extratropical cyclone on Monday.  Thunderstorms were still occurring in bands in the eastern and northern parts of Koguma’s circulation.  Bands in the western and southern parts of Typhoon Koguma consisted primarily of showers and lower clouds.  Storms near the center of Koguma generated upper level divergence that pumped mass away to the northeast of 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 Monday.

Even though Typhoon Koguma started a transition to an extratropical cyclone on Monday, the distribution of wind speeds was still fairly symmetrical.  Winds to typhoon force extended out 60 miles (95 km) from the center of Koguma’s circulation.  Winds to tropical storm force extended out 140 miles (225 km) from the center of Typhoon Koguma.

Typhoon Koguma will move through an environment that will be unfavorable for intensification of a typhoon during the next 24 hours.  Koguma will move over water where the Sea Surface Temperatures are near 22°C.  It will move under the eastern side of an upper level trough that is east of Japan.  The upper level trough will produce southwesterly winds that will blow toward the top of Koguma’s circulation.  Those winds will cause strong vertical wind shear.  Typhoon Koguma will continue to weaken on Tuesday as it makes a transition to a strong extratropical cyclone.

The upper level trough that is east of Japan will steer Typhoon Koguma quickly toward the northeast during the next 24 hours.  On its anticipated track, Typhoon Koguma will move farther away from Japan.