Tag Archives: HWISI

Fernanda Rapidly Intensifies to a Major Hurricane

Hurricane Fernanda rapidly intensified to a major hurricane over the Eastern North Pacific Ocean during Sunday night. At 5:00 a.m. EDT on Monday the center of Hurricane Fernanda was located at latitude 15.6°N and longitude 117.7°W which put it about 715 miles (1150 km) southwest of the southern tip of Baja California. Fernanda was moving toward the west at 8 m.p.h. (13 km/h). The maximum sustained wind speed was 125 m.p.h. (200 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 959 mb.

Hurricane Fernanda continued to intensify rapidly during Sunday night. A small eye was at the center of Fernanda’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 revolved around the core of Hurricane Fernanda. Storms near the core generated upper level divergence that pumped mass away from the hurricane.

The circulation around Hurricane Fernanda was small. Winds to hurricane force extended out 25 miles (40 km) from the center of Fernanda’s circulation. Winds to tropical storm force extended out 70 miles (110 km) from the center of circulation. The Hurricane Intensity Index (HII) was 23.6. The Hurricane Size Index (HSI) was 7.8 and the Hurricane Wind Intensity Size Index (HWISI) was 31.4.

Hurricane Fernanda will move through an environment favorable for intensification during the next 12 hours. Fernanda 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. Hurricane Fernanda is likely to continue to intensify during the next 12 hours. Fernanda will move over slightly cooler water on Tuesday. The cooler water will cause Fernanda to start to weaken.

Hurricane Fernanda will move south of a subtropical high pressure system over the Eastern North Pacific Ocean. The high pressure system will steer Fernanda toward the west during the next 24 hours. On its anticipated track, Hurricane Fernanda will move farther away from Baja California.

Elsewhere, Tropical Storm Greg formed east-southeast of Hawaii. At 5:00 a.m. EDT on Monday the center of Tropical Storm Greg was located at latitude 11.3°N and longitude 139.8°W which put it about 1170 miles (1885 km) east-southeast of Hilo, Hawaii. Greg was moving toward the west at 13 m.p.h. (21 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 1005 mb. Tropical Storm Greg is forecast to pass south of Hawaii later this week.

Typhoon Lan Approaches Honshu

Typhoon Lan was approaching Honshu on Sunday night. At 11:00 p.m. EDT on Sunday the center of Typhoon Lan was located at latitude 32.1°N and longitude 137.2°E which put it about 120 miles (195 km) south-southeast of Shingu, Japan. Lan was moving toward the northwest at 9 m.p.h. (15 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 959 mb.

Typhoon Lan strengthened as it approached Honshu on Sunday. A large circular eye with a diameter of 60 miles (95 km) was at the center of Lan’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 large core of Typhoon Lan. Storms near the core generated upper level divergence that pumped mass away from the typhoon.

There was a large circulation around Typhoon Lan. Winds to typhoon force extended out 70 miles (110 km) from the center of Lan’s circulation. Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Lan was 16.5. The Hurricane Size Index (HSI) was 21.3 and the Hurricane Wind Intensity Size Index (HWISI) was 37.8. Typhoon Lan was capable of causing widespread serious damage.

Typhoon Lan will move through an environment favorable for intensification during the next 12 hours. Lan 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 Lan could continue to strengthen during the next 12 hours as it approaches Honshu.

Typhoon Lan will move around the western part of a high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Lan toward the northwest during the next 24 hours. On its anticipated track, the center of Typhoon Lan will make landfall in Wakayama Prefecture south of Osaka in about 18 hours. Lan will produce strong gusty winds and locally heavy rain over parts of Honshu. Heavy rain is likely to cause flash floods in some locations.

Elsewhere over the Western North Pacific Ocean, former Tropical Storm Dora continue to weaken east of Wake Island. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Dora was located at latitude 19.0°N and longitude 169.7°E which put it about 235 miles (380 km) east of Wake Island. Dora was moving toward the west-northwest at 15 m.p.h. (24 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 1005 mb.

Typhoon Lan Continues to Move Toward Honshu

Typhoon Lan continued to move to Honshu on Saturday night. At 11:00 p.m. EDT on Saturday the center of Typhoon Lan was located at latitude 30.0°N and longitude 139.1°E which put it about 385 miles (625 km) south of Tokyo, Japan. Lan was moving toward the northwest at 8 m.p.h. (11 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 970 mb.

Typhoon Lan completed an eyewall replacement cyclone on Saturday. The smaller, inner eye and eyewall dissipated. A circular eye with a diameter of 70 miles (110 km) was at the center of Lan’s circulation on Saturday night. The large 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 large eye. Storms around the eye generated upper level divergence that pumped mass away from the typhoon.

The area of typhoon force winds in Typhoon Lan increased during the eyewall replacement cycle. Winds to typhoon force extended out 70 miles (110 km) from the center of Lan’s circulation. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Lan was 11.5. The Hurricane Size Index (HSI) was 21.1 and the Hurricane Wind Intensity Size Index (HWISI) was 32.6.

Typhoon Lan will move through an environment favorable for intensification during the next 24 hours. Lan 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 Lan could strengthen during the next 24 hours, since the eyewall replacement cycle is complete.

Typhoon Lan will move around the western part of a high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Lan toward the northwest during the next 24 hours. On its anticipated track, Typhoon Lan will approach Honshu in less than 48 hours. The center of Lan could make landfall south of Osaka. Lan will be a typhoon when it reaches Honshu.

Elsewhere over the Western North Pacific Ocean, former Hurricane Dora weakened to a tropical storm East of Wake Island. At 11:00 p.m. EDT on Saturday the center of Tropical Storm Dora was located at latitude 18.2°N and longitude 174.7°E which put it about 570 miles (920 km) east of Wake Island. Dora was moving toward the west-northwest at 14 m.p.h. (22 km/h). The maximum sustained wind speed was 65 m.p.h. (105 km/h) and there were wind gusts to 80 m.p.h. (130 km/h). The minimum surface pressure was 996 mb.

Typhoon Lan Moves Toward Honshu

Typhoon Lan moved toward Honshu on Friday. At 11:00 p.m. EDT on Friday the center of Typhoon Lan was located at latitude 28.7°N and longitude 141.5°E which put it about 485 miles (785 km) south-southeast of Tokyo, Japan. Lan was moving toward the west-northwest 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 960 mb.

Typhoon Lan was weakening on Friday night. The inner of a rainband wrapped around the existing eye and eyewall and a larger, outer eyewall formed. The formation of concentric eyewalls was disrupting the low level convergence into the inner eyewall and the inner eyewall was weakening. Since the strongest winds were occurring in the inner eyewall, the maximum wind speed decreased when the inner eyewall weakened. Bands of showers and thunderstorms were revolving around the concentric eyewalls. Storms around the concentric eyewalls generated upper level divergence that pumped mass away from the typhoon.

Winds to typhoon force extended out 35 miles (55 km) from the center of Typhoon Lan. Winds to tropical storm force extended out 140 miles (225 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Lan was 16.5. The Hurricane Size Index (HSI) was 11.4 and the Hurricane Wind Intensity Size Index (HWISI) was 27.9.

Typhoon Lan will move through an environment favorable for intensification during the next 24 hours. Lan 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 Lan is likely to weaken during the next 24 hours even though it will be in a favorable environment. The maximum wind speed is likely to continue to decrease as the inner eyewall dissipates.

Typhoon Lan will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Lan toward the northwest during the next 24 hours. On its anticipated track, Typhoon Lan will approach Honshu in less than 72 hours. Lan is likely to be a typhoon when it approaches Honshu.

Hurricane Dora Moves Across the International Date Line

Hurricane Dora moved across the International Date Line on Friday night. At 11:00 p.m. EDT on Friday the center of Hurricane Dora was located at latitude 15.9°N and longitude 179.4°E which put it about 860 miles (1390 km) south of Midway Island. Dora was moving toward the west-northwest at 18 m.p.h. (30 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 972 mb.

Hurricane Dora was weakening as it moved across the International Date Line on Friday night. Dora was moving under the western part of an upper level ridge over the Central Pacific Ocean. The ridge was producing southerly winds that were blowing toward the top of Dora’s circulation. Those winds were causing the vertical wind shear to increase and the wind shear was causing Hurricane Dora to weaken.

There still was a small eye at the center of Hurricane Dora. 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 Dora’s circulation. 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 25 miles (40 km) from the center of Dora. Winds to tropical storm force extended out 90 miles (145 km) from the center of circulation. The Hurricane Intensity Index (HII) was 17.8. The Hurricane Size Index (HSI) was 7.0 and the Hurricane Wind Intensity Size Index (HWISI) was 24.8.

Hurricane Dora will move through an environment that will be unfavorable for intensification during the next 24 hours. Dora will move over water where the Sea Surface Temperatures are near 28°C. However, the upper level ridge will continue to cause moderate to strong vertical wind shear. The wind shear will cause Hurricane Dora to weaken during the next 24 hours. Dora could weaken quickly even though it is over warm water, because it is such a small hurricane.

Hurricane Dora will move around the western side of a high pressure system over the Central Pacific Ocean. The high pressure system will steer Dora toward the west-northwest during the next 24 hours. On its anticipated track Hurricane Dora could be east of Wake Island in 48 hours.

Typhoon Lan Rapidly Intensifies to Equivalent of a Major Hurricane

Typhoon Lan rapidly intensified to the equivalent of a major hurricane over the Western North Pacific Ocean south of Japan on Thursday. At 11:00 p.m. EDT on Thursday the center of Typhoon Lan was located at latitude 27.1°N and longitude 142.8°E which put it about 615 miles (995 km) south-southeast of Tokyo, Japan. Lan was moving toward the north at 6 m.p.h. (10 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 936 mb.

Typhoon Lan intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Thursday. A circular eye with a diameter of 28 miles (45 km) developed at the center of Lan’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 Lan. Storms near the core generated upper level divergence that pumped mass away from the typhoon in all directions. The removal of large quantities of mass caused the surface pressure to decrease rapidly.

The size of the circulation around Typhoon Lan increased when Lan intensified rapidly on Thursday. Winds to typhoon force extended out 45 miles (75 km) from the center of Lan’s circulation. Winds to tropical storm force extended out 160 miles (260 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Lan was 25.1. The Hurricane Size Index (HSI) was 14.0 and the Hurricane Wind Intensity Size (HWISI) was 39.1. Typhoon Lan was similar in size and intensity to Hurricane Harvey when Harvey hit Texas in 2017.

Typhoon Lan will move through an environment favorable for intensification during the next 24 hours. Lan 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 Lan is likely 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 Typhoon Lan to weaken.

Typhoon Lan will move around the western part of a high pressure system over the Western North Pacific Ocean. The high pressure system will steer Lan toward the northwest during the next 24 hours. On its anticipated track, Typhoon Lan will bring strong, gusty winds and locally heavy rain to Chichi Jima during the next 24 hours. Typhoon Lan could approach Honshu in four days.

Elsewhere over the Western North Pacific Ocean, former Tropical Storm Khanun produced gusty winds and locally heavy rain over South Korea. At 5:00 p.m. EDT on Thursday the center of Tropical Depression Khanun was located at latitude 38.9°N and longitude 127.0°E which put it about 85 miles (135 km) north-northeast of Seoul, South Korea. Khanun was moving toward the northwest at 9 m.p.h. (15 km/h). The maximum sustained wind speed was 30 m.p.h. (50 km/h) and there were wind gusts to 40 m.p.h. (65 km/h). The minimum surface pressure was 994 mb.

Hurricane Dora Passes South of Johnston Island

Hurricane Dora passed south of Johnston Island early on Thursday. At 5:00 a.m. EDT on Thursday the center of Hurricane Dora was located at latitude 12.1°N and longitude 169.8°W which put it about 320 miles (510 km) south of Johnston Island. Dora was moving toward the west at 22 m.p.h. (35 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 950 mb.

The structure of Hurricane Dora showed signs of changing early on Thursday. The eye at the center of Dora’s circulation got smaller and the eye was more difficult to see on infrared satellite images. Several new bands of thunderstorms developed in the eastern and northern parts of Hurricane Dora. Dora was still a powerful hurricane. Storms near the center of Dora generated upper level divergence that pumped mass away from the hurricane.

The size of the circulation around Hurricane Dora increased a little as its structure began to change. Winds to hurricane force extended out 30 miles (50 km) from the center of Dora’s circulation. Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation. The Hurricane Intensity Index (HII) was 28.3. The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 38.2. Hurricane Dora was similar in size and intensity to Hurricane Charley when Charley hits southwest Florida in 2004.

Hurricane Dora will move through an environment that will be favorable for a major hurricane during the next 24 hours. Dora 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. Hurricane Dora could be starting an eyewall replacement cycle. If an eyewall replacement cycle is beginning, then Dora is likely to weaken during the next 24 hours, even though the hurricane will be in a favorable environment. Since the circulation around Hurricane Dora is so small, any changes in the environment will have large effects on the intensity of Dora.

Hurricane Dora will move south of a subtropical high pressure system over the North Pacific Ocean. The high pressure system will steer Dora toward the west-northwest during the next 24 hours. On its anticipated track, Hurricane Dora will be move west of the International Date Line on Friday.

Hurricane Dora Passes South of Hawaii

Hurricane Dora passed south of Hawaii on Tuesday. At 11:00 p.m. EDT on Tuesday the center of Hurricane Dora was located at latitude 11.4°N and longitude 160.1°W which put it about 700 miles (1125 km) south-southwest of Honolulu, Hawaii. Dora was moving toward the west at 23 m.p.h. (37 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 953 mb.

Hurricane Dora changed very little on Tuesday. The structure of Dora continued to be very symmetrical. An eye with a diameter of 12 miles (19 km) was still at the center of Hurricane Dora. 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 Dora’s circulation. Storms near the core generated upper level divergence that pumped mass away from the hurricane.

The size of the circulation around Hurricane Dora did not change much on Tuesday either. Winds to hurricane force extended out 30 miles (50 km) from the center of Dora’s circulation. Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation. The Hurricane Intensity Index (HII) was 25.1. The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 35.0.

Hurricane Dora will move through an environment that will be favorable for a major hurricane during the next 24 hours. Dora will move over water where the Sea Surface Temperatures are near 27°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Dora has been in equilibrium with its environment during the past 24 hours. The intensity of Dora may not change much during the next 24 hours. Since the circulation around Hurricane Dora is so small, any changes in the environment will have large effects on the intensity of Dora.

Hurricane Dora will move south of a subtropical high pressure system over the North Pacific Ocean. The high pressure system will steer Dora toward the west during the next 24 hours. On its anticipated track, Hurricane Dora will be near Johnston Island on Thursday.

Hurricane Dora Moves Southeast of Hawaii

Hurricane Dora moved southeast of Hawaii on Monday. At 11:00 p.m. EDT on Monday the center of Hurricane Dora was located at latitude 12.0°N and longitude 152.3°W which put it about 565 miles (905 km) south-southeast of Hilo, Hawaii. Dora was moving toward the west at 23 m.p.h. (37 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 953 mb.

Hurricane Dora weakened slightly on Monday. The structure of Dora continued to be very symmetrical. An eye with a diameter of 12 miles (19 km) was at the center of Hurricane Dora. 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 Dora’s circulation. Storms near the core generated upper level divergence that pumped mass away from the hurricane.

The size of the circulation around Hurricane Dora increased a little on Monday. Winds to hurricane force extended out 30 miles (50 km) from the center of Dora’s circulation. Winds to tropical storm force extended out 115 miles (185 km) from the center of circulation. The Hurricane Intensity Index (HII) was 25.1. The Hurricane Size Index (HSI) was 9.9 and the Hurricane Wind Intensity Size Index (HWISI) was 35.0.

Hurricane Dora will move through an environment that will be favorable for a major hurricane during the next 24 hours. Dora will move over water where the Sea Surface Temperatures are near 26.5°C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Dora could move into a region where the air is a little drier. Since the circulation around Hurricane Dora is so small, any changes in the environment will have large effects on the intensity of Dora. Hurricane Dora could weaken a little more during the next 24 hours because of the drier air.

Hurricane Dora will move south of a subtropical high pressure system over the North Pacific Ocean. The high pressure system will steer Dora toward the west during the next 24 hours. On its anticipated track, Hurricane Dora will pass south of Hawaii on Tuesday.

Elsewhere, former Tropical Storm Eugene weakened west of Baja California on Monday. At 5:00 p.m. EDT on Monday the center of Tropical Depression Eugene was located at latitude 25.1°N and longitude 120.4°W which put it about 680 miles (1095 km) west-northwest of the southern tip of Baja California. Eugene was moving toward the west-northwest at 14 m.p.h. (22 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 1008 mb.

Hurricane Dora Moves over the Central Pacific

Hurricane Dora moved over the Central Pacific Ocean on Sunday. At 11:00 p.m. EDT on Sunday the center of Hurricane Dora was located at latitude 12.7°N and longitude 144.0°W which put it about 890 miles (1430 km) east-southeast of the South Point, Hawaii. Dora was moving toward the west at 22 m.p.h. (35 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. (270 km/h). The minimum surface pressure was 950 mb.

Hurricane Dora did not change much on Sunday. The structure of Dora continued to be very symmetrical and it had a a shape sometimes called an annular hurricane. An eye with a diameter of 17 miles (28 km) was at the center of Hurricane Dora. 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 Dora’s circulation. Storms near the core generated upper level divergence that pumped mass away from the hurricane.

The circulation around Hurricane Dora was still very small. Winds to hurricane force extended out 25 miles (40 km) from the center of Dora’s circulation. Winds to tropical storm force extended out 70 miles (110 km) from the center of circulation. The Hurricane Intensity Index (HII) was 28.3. The Hurricane Size Index (HSI) was only 7.0 and the Hurricane Wind Intensity Size Index (HWISI) was 35.36. Hurricane Dora was similar in size and intensity to Hurricane Charley when Charley hit southwest Florida in 2004.

Hurricane Dora will move through an environment that will be favorable for a powerful hurricane during the next 24 hours. Dora will move over water where the Sea Surface Temperatures are near 26.5C. It will move through a region where the upper level winds are weak and there will be little vertical wind shear. Hurricane Dora could move into a region where the air is a little drier. The intensity of an annual hurricane usually remains relatively constant. However, since the circulation around Hurricane Dora is so small, any changes in the environment will have large effects on the intensity of Dora. Hurricane Dora could weaken a little during the next 24 hours, if it moves into a region where the air is a little drier.

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 during the next 24 hours. On its anticipated track, Hurricane Dora will pass south of Hawaii on Tuesday.

Elsewhere over the Eastern North Pacific Ocean, Tropical Storm Eugene moved south of Baja California on Sunday. At 11:00 p.m. EDT on Sunday the center of Tropical Storm Eugene was located at latitude 23.3°N and longitude 115.0°W which put it about 325 miles (525 km) west of the southern tip of Baja California. Eugene was moving toward the west-northwest at 20 m.p.h. (32 km/h). 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 997 mb. Tropical Storm Eugene will weaken on Monday as it moves over cooler water west of Baja California.