Monthly Archives: August 2023

Large Typhoon Khanun Churns West of Okinawa

Large Typhoon Khanun churned over the Western North Pacific Ocean west of Okinawa on Wednesday night. At 11:00 p.m. EDT on Wednesday the center of Typhoon Khanun was located at latitude 26.6°N and longitude 124.6°E which put it about 190 miles (310 km) west of Okinawa. Khanun was moving toward the west-northwest at 4 m.p.h. (6 km/h). The maximum sustained wind speed was 105 m.p.h. (1650 km/h) and there were wind gusts to 125 m.p.h. (200 km/h). The minimum surface pressure was 951 mb.

The inner end of a rainband wrapped around an existing eye and eyewall on Wednesday and concentric eyewalls formed in Typhoon Khanun. The inner eye had a diameter of 15 miles (25 km). The inner eye was surrounded by a ring of thunderstorms and the strongest winds were occurring in that ring of storms. The inner eyewall was surrounded by a large clear area called a moat. The moat was surrounded by a large outer eyewall that had a diameter of 115 miles (185 km). Bands of showers and thunderstorms were revolving around the concentric eyewalls. Storms in the concentric eyewalls generated upper level divergence that pumped mass away from the typhoon.

The size of the circulation around Typhoon Khanun increased when the concentric eyewalls formed. Winds to typhoon force extended out 115 miles (185 km) from the center of Khanun’s circulation. Winds to tropical storm force extended out 235 miles (380 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Khanun was 17.8. The Hurricane Size Index (HSI) was 37.0 and the Hurricane Wind Intensity Size Index (HWISI) was 54.8. Khanun is capable of causing extensive serious damage. Typhoon Khanun was large than Hurricane Ivan was when Ivan hit the U.S. Gulf Coast in 2004. Khanun was not quite as strong as Ivan was.

Typhoon Khanun will move through an environment that will be favorable for a strong typhoon during the next 24 hours. Khanun 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. However, Typhoon Khanun is likely to weaken during the next 24 hours, because of the concentric eyewalls. The inner eyewall is likely to weaken and the low level convergence will occur into the large, outer eyewall. Since the strongest winds are in the inner eyewall, the wind speed will decrease when the inner eyewall weakens.

Typhoon Khanun will be in an area where the steering currents are weak during the next 24 hours. On its anticipated track, Typhoon Khanun will meander west of Okinawa during the next 24 hours. Khanun is forecast to move back toward the east-northeast later this week. The center of Typhoon Khanun could pass north of Okinawa on Friday. Khanun is forecast move across the northern Ryukyu Islands in 48 hours. Typhoon Khanun will continue to produce strong, gusty winds and locally heavy rain in Okinawa and other Ryukyu Islands. Heavy rain will cause flash floods in some locations.

Dora Rapidly Intensifies to a Hurricane

Former Tropical Storm Dora rapidly intensified to a hurricane over the Eastern North Pacific Ocean southwest of Mexico on Tuesday evening. At 11:00 p.m. EDT on Tuesday the center of Hurricane Dora was located at latitude 16.2°N and longitude 111.5°W which put it about 510 miles (825 km) west-southwest of Manzanillo, Mexico. Dora was moving toward the west at 16 m.p.h. (26 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 994 mb.

A microwave satellite image showed that the inner end of a rainband had wrapped around the center of Hurricane Dora on Tuesday evening. A very small eye was at the center of Dora on the microwave image. The eye was surrounded by a tight ring of thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the small core of Hurricane Dora. Storms near the core generated upper level divergence that pumped mass away from the hurricane.

The circulation around Hurricane Dora was small. Winds to hurricane force extended out 15 miles (25 km) from the center of Dora’s circulation. Winds to tropical storm force extended out 45 miles (75 km) from the center of circulation.

Hurricane Dora will move through an environment favorable for intensification during the next 36 hours. Dora will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the center of an upper level ridge over the Eastern North Pacific. The upper level winds are weak near the center of the ridge and there will be little vertical wind shear. Hurricane Dora will intensify during the next 36 hours. Since the circulation around Dora is so small, any changes in the environment will have large effects on the rate of intensification. Dora could continue to intensify rapidly as long as it remains in a favorable environment. Hurricane Dora is could strengthen to a major hurricane by Thursday.

Hurricane Dora will move south of a subtropical high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Dora toward the west-southwest during the next few days. On its anticipated track, Hurricane Dora will move farther away from Mexico. Dora could move over the Central Pacific Ocean by the end of the upcoming weekend.

Typhoon Khanun Brings Wind and Rain to Okinawa

Typhoon Khanun brought wind and rain to Okinawa on Tuesday. At 5:00 p.m. EDT on Tuesday the center of Typhoon Khanun was located at latitude 25.7°N and longitude 127.1°E which put it about 50 miles (80 km) south-southwest of Okinawa. Khanun was moving toward the west-northwest at 7 m.p.h. (11 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 155 m.p.h. (250 km/h). The minimum surface pressure was 941 mb.

Typhoon Khanun brought strong, gusty winds and locally heavy rain to Okinawa on Tuesday. The eye and eyewall at the center of Khanun’s circulation passed just south of Okinawa. Bands in the northern part of Typhoon Khanun moved across Okinawa. A weather station at Kadena Air Force Base reported a sustained wind speed of 74 m.p.h. (119 km/h). The weather station reported a wind gust to 87 m.p.h. (141 km/h).

An eye with a diameter of 25 miles (40 km) was at the center of Typhoon Khanun. 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 Typhoon Khanun. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

The circulation around Typhoon Khanun was large. Winds to typhoon force extended out 65 miles (105 km) from the center of Khanun’s circulation. Winds to tropical storm force extended out 200 miles (320 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Khanun was 23.6. The Hurricane Size Index (HSI) was 18.2 and the Hurricane Wind Intensity Size Index (HWISI) was 41.8. Khanun is capable of causing regional major damage. Typhoon Khanun was as strong as Hurricane Dennis was when Dennis hit Northwest Florida in 2005. Khanun was much larger than Dennis was.

Typhoon Khanun will move through an environment that will become less favorable for a strong typhoon during the next 24 hours. Khanun 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. However, there is a region of drier air northwest of the Ryukyu Islands. Some of the drier air could get pulled into the western half of Typhoon Khanun. The drier air is likely to cause Typhoon Khanun to weaken during the next 24 hours. Khanun is likely to move slowly during the next few days. Strong winds near the surface will mix cooler water to the surface of the ocean. Typhoon Khanun will extract less energy from the ocean and it is likely to continue to weaken later this week.

Typhoon Khanun will move around the southwestern side of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Khanun toward the west-northwest during the next 24 hours. On its anticipated track, the core of Typhoon Khanun move west of Okinawa during the next 24 hours. The steering currents are likely to weaken later this week and Typhoon Khanun could meander near the Ryukyu Islands for several days. Khanun will continue to bring strong, gusty winds and locally heavy rain to Okinawa and the other southern Ryukyu Islands. Heavy rain will cause flash floods in some locations. Typhoon Khanun will also cause a significant storms surge in the parts of islands where the winds blow water toward the coast.

Tropical Storm Dora Forms Southwest of Mexico

Tropical Storm Dora formed over the Eastern North Pacific Ocean southwest of Mexico on Tuesday morning. At 5:00 a.m. EDT on Tuesday the center of Tropical Storm Dora was located at latitude 16.0°N and longitude 107.1°W which put it about 275 miles (445 km) southwest of Manzanillo, Mexico. Dora was moving toward the west-northwest 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 1006 mb.

The circulation around Tropical Storm Dora was organizing quickly on Tuesday morning. The inner end of a rainband wrapped around the western and southern sides of Dora’s circulation. An eye appeared to be forming at the center of Tropical Storm Dora. Bands of showers and thunderstorms were revolving around the developing inner core of Dora. Storms near the core generated upper level divergence that pumped mass away from the tropical storm. Winds to tropical storm force extended out 45 miles (75 km) from the center of Dora.

Tropical Storm Dora will move through an environment very favorable for intensification during the next 36 hours. Dora will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the center of an upper level ridge over the Eastern North Pacific. The upper level winds are weak near the center of the ridge and there will be little vertical wind shear. Tropical Storm Dora will intensify during the next 36 hours. Dora could intensify rapidly at times, especially after the inner core with an eye and eyewall fully form. Tropical Storm Dora is likely to strengthen to a hurricane by Wednesday.

Tropical Storm Dora will move south of a subtropical high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Dora toward the west during the next few days. On its anticipated track, Tropical Storm Dora will move farther away from Mexico.

Typhoon Khanun Approaches Okinawa

Typhoon Khanun was approaching Okinawa on Monday night. At 11:00 p.m. EDT on Monday the center of Typhoon Khanun was located at latitude 24.8°N and longitude 129.1°E which put it about 165 miles (265 km) southeast of Okinawa. Khanun was moving toward the west-northwest at 12 m.p.h. (19 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 930 mb.

Typhoon Khanun continued to strengthen on Monday. A circular eye with a diameter of 30 miles (50 km) was at the center of Khanun’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 Typhoon Khanun. Storms near the core generated strong upper level divergence that pumped mass away form the typhoon in all directions.

The core of Typhoon Khanun contracted on Monday as Khanun intensified. Winds to typhoon force extended out 50 miles (80 km) from the center of Khanun’s circulation. Winds to tropical storm force extended out 265 miles (425 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Khanun was 28.3. The Hurricane Size Index (HSI) was 17.4 and the Hurricane Wind Intensity Size Index (HWISI) was 45.7. Khanun is capable of causing regional severe damage. Typhoon Khanun was almost as strong as Hurricane Ida was when Ida hit Louisiana in 2021. Khanun was larger than Ida was.

Typhoon Khanun will move through an environment that will be favorable for a strong typhoon during the next 24 hours. Khanun 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 Khanun could intensify during the next 24 hours unless an eyewall replacement cycle occurs. If the inner end of a rainband wraps around the existing eye and eyewall, then concentric eyewalls could develop. The formation of concentric eyewalls would cause Khanun to weaken.

Typhoon Khanun will move around the southwestern side of a subtropical high pressure system over the Western North Pacific Ocean. The high pressure system will steer Khanun toward the west-northwest during the next 24 hours. On its anticipated track, the core of Typhoon Khanun will be just south of Okinawa in 12 hours. Khanun will bring strong, gusty winds and locally heavy rain to Okinawa and the other southern Ryukyu Islands. Heavy rain will cause flash floods in some locations. Typhoon Khanun will also cause a significant storms surge in the parts of islands where the winds blow water toward the coast.