Tag Archives: HWISI

Tropical Cyclone Batsirai Brings Wind and Rain to Mauritius

Tropical Cyclone Batsirai brought wind and rain to Mauritius on Wednesday. At 10:00 a.m. EST on Wednesday the center of Tropical Cyclone Batsirai was located at latitude 19.0°S and longitude 56.3°E which put it about 90 miles (145 km) north-northwest of Port Louis, Mauritius. Batsirai was moving toward the west-southwest at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 145 m.p.h. (235 km/h) and there were wind gusts to 175 m.p.h. (280 km/h). The minimum surface pressure was 931 mb.

The core of Tropical Cyclone Batsirai passed north of Mauritius on Wednesday, but it still brought wind and rain. A weather station at Champ de Mars, near Port Louis, reported a wind speed of 94 m.p.h. (151 km/h). Another weather station near Port Louis at Bell Village reported 6.01 inches (152.7 mm) of rain.

Tropical Cyclone Batsirai appeared to undergo an eyewall replacement cycle. The tiny inner eyewall dissipated and a new larger eye was apparent on satellite images. Batsirai may have been near Category 5 on the Saffir-Simpson Scale before the inner eyewall dissipated. The new eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Batsirai. Storms near the core generated strong upper level divergence that pumped large quantities of mass away from the tropical cyclone.

The size of the circulation around Tropical Cyclone Batsirai increased during the eyewall replacement cyclone. Winds to hurricane/typhoon force extended out 65 miles (105 km) from the center of Batsirai. Winds to tropical storm force extended out 215 miles (345 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Batsirai was 29.9. The Hurricane Size Index (HSI) was 23.1 and the Hurricane Wind Intensity Size Index (HWISI) was 53.0.

Tropical Cyclone Batsirai will move through an environment capable of supporting a strong tropical cyclone during the next 36 hours. Batsirai 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. Tropical Cyclone Batsirai weakened after the eyewall replacement cycle, but it could strengthen again since the inner core is still intact. There is a chance that Batsirai could reach Category 5 on the Saffir-Simpson Scale.

Tropical Cyclone Batsirai will move north of a high pressure system over the South Indian Ocean. The high pressure system will steer Batsirai toward the west-southwest during the next several days. Weather conditions on Mauritius will improve gradually as Batsirai moves farther away. On its anticipated track the center of Tropical Cyclone Batsirai will pass north of La Reunion during the next 24 hours. Although the strongest winds in Batsirai will pass north of La Reunion, it could experience strong winds and locally heavy rain. Locally heavy rain could cause flash floods in some locations. Tropical Cyclone Batsirai could reach the east coast of Madagascar within 60 hours. Batsirai is likely to be the equivalent of a major hurricane when it reaches Madagascar.

Tropical Cyclone Batsirai Rapidly Intensifies to Equivalent of a Major Hurricane

Tropical Cyclone Batsirai rapidly intensified to the equivalent of a major hurricane on Tuesday night. At 10:00 p.m. EST on Tuesday the center of Tropical Cyclone Batsirai was located at latitude 18.3°S and longitude 57.9°E which put it about 155 miles (250 km) northeast of Port Louis, Mauritius. Batsirai was moving toward the southwest 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. (270 km/h). The minimum surface pressure was 915 mb.

Tropical Cyclone Batsirai rapidly intensified to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Tuesday night. The core of Batsirai contracted around a tiny pinhole eye. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Batsirai. Storms near the core generated strong upper level divergence that large quantities of mass away from the tropical cyclone. The removal of that much mass allowed the surface pressure to decrease rapidly.

Tropical Cyclone Batsirai increased in size as it intensified rapidly. Winds to hurricane/typhoon force extended out 45 miles (75 km) from the center of Batsirai. Winds to tropical storm force extended out 195 miles (315 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Batsirai was 28.3. The Hurricane Size Index (HSI) was 18.3 and the Hurricane Wind Intensity Size Index (HWISI) was 46.6.

Tropical Cyclone Batsirai will move through an environment capable of supporting a strong tropical cyclone during the next 48 hours. Batsirai will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the northern part of an upper level ridge over the Southwest Indian Ocean. The ridge will produced easterly winds that will blow toward the top of Batsirai’s circulation. Those winds will cause some vertical wind shear and the wind shear could inhibit additional intensification. If the inner end of a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could begin. If an eyewall replacement cycle occurs Tropical Cyclone Batsirai is likely to weaken, at least temporarily.

Tropical Cyclone Batsirai will move north of a high pressure system over the South Indian Ocean. The high pressure system will steer Batsirai toward the west-southwest during the next several days. On its anticipated track the center of Tropical Cyclone Batsirai will pass north of Mauritius during the next 12 hours. Although the strongest winds in Batsirai will pass north of Mauritius, it could experience tropical storm force winds and locally heavy rain. Locally heavy rain could cause flash floods in some locations. Tropical Cyclone Batsirai will be north of La Reunion in 24 hours. Batsirai could reach the east coast of Madagascar within 72 hours. Tropical Cyclone Batsirai could still be the equivalent of a major hurricane when it reaches Madagascar.

Tropical Cyclone Batsirai Churns Northeast of Mauritius

Tropical Cyclone Batsirai churned northeast of Mauritius on Tuesday morning. At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Batsirai was located at latitude 17.4°S and longitude 59.7°E which put it about 270 miles (440 km) northeast of Port Louis, Mauritius. Batsirai was moving toward the west-northwest at 11 m.p.h. (17 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 966 mb.

Tropical Cyclone Batsirai intensified slowly over the Southwest Indian Ocean northeast of Mauritius on Tuesday morning. A small circular eye was present at the center of Batsirai’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Batsirai. Storms near the core generated upper level divergence that pumped mass away from the tropical cyclone.

The core of Tropical Cyclone Batsirai contracted on Tuesday morning, but the overall size of the circulation increased. Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Batsirai. Winds to tropical storm force extended out 145 miles (235 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Batsirai was 17.8. The Hurricane Size Index (HSI) was 11.3 and the Hurricane Wind Intensity Size Index (HWISI) was 29.1.

Tropical Cyclone Batsirai will move through an environment favorable for intensification during the next 36 hours. Batsirai will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the northern part of an upper level ridge over the Southwest Indian Ocean. The ridge will produced easterly winds that will blow toward the top of Batsirai’s circulation. Those winds will cause some vertical wind shear and the wind shear could inhibit intensification. Tropical Cyclone Batsirai is likely to intensify during the next 24 hours. Batsirai could strengthen to the equivalent of a major hurricane during the next day or two.

Tropical Cyclone Batsirai will move north of a high pressure system over the South Indian Ocean. The high pressure system will steer Batsirai toward the west-southwest during the next several days. On its anticipated track the center of Tropical Cyclone Batsirai will pass north of Mauritius during the next 24 hours. Although the strongest winds in Batsirai will pass north of Mauritius, it could experience tropical storm force winds and locally heavy rain. Locally heavy rain could cause flash floods in some locations. Tropical Cyclone Batsirai could be north of La Reunion in 36 hours. Batsirai could reach the east coast of Madagascar within 72 hours.

Tropical Cyclone Batsirai Passes North of Rodrigues

Tropical Cyclone Batsirai passed north of Rodrigues on Sunday night. At 10:00 a.m. EST on Monday the center of Tropical Cyclone Batsirai was located at latitude 15.7°S and longitude 62.9°E which put it about 495 miles (795 km) northeast of Port Louis, Mauritius. Batsirai 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 125 m.p.h. (200 km/h). The minimum surface pressure was 969 mb.

The center of Tropical Cyclone Batsirai passed north of Rodrigues on Sunday night. The circulation around Batsirai remained well organized. A small circular eye was at the center of Batsirai’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Batsirai. Storms near the core generated upper level divergence that pumped mass away from the tropical cyclone.

The circulation around Tropical Cyclone Batsirai increased in size on Sunday. Winds to hurricane/typhoon force extended out 60 miles (95 km) from the center of Batsirai. Winds to tropical storm force extended out 120 miles (195 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Batsirai was 16.5. The Hurricane Size Index (HSI) was 13.8 and the Hurricane Wind Intensity Size Index (HWISI) was 30.3.

Tropical Cyclone Batsirai will move through an environment favorable for intensification during the next 36 hours. Batsirai will move over water where the Sea Surface Temperatures are near 29˚C. It will move under the northern part of an upper level ridge over the South Indian Ocean. The ridge will produced easterly winds that will blow toward the top of Batsirai’s circulation. Those winds will cause some vertical wind shear and the wind shear could inhibit intensification. Tropical Cyclone Batsirai could strengthen during the next 24 hours. Batsirai could strengthen to the equivalent of a major hurricane during the next day or two.

Tropical Cyclone Batsirai will move north of a high pressure system over the South Indian Ocean. The high pressure system will steer Batsirai toward the west-southwest during the next several days. On its anticipated track the center of Tropical Cyclone Batsirai could be north of Mauritius in 48 hours. Batsirai could be the equivalent of a major hurricane when it is north of Mauritius. Tropical Cyclone Batsirai could approach La Reunion in 60 hours. Batsirai could also eventually affect Madagascar later next week.

Tropical Cyclone Batsirai Intensifies Northeast of Rodrigues

Tropical Cyclone Batsirai intensified northeast of Rodrigues on Sunday morning. At 10:00 a.m. EST on Sunday the center of Tropical Cyclone Batsirai was located at latitude 16.7°S and longitude 65.7°E which put it about 255 miles (410 km) northeast of Rodrigues. Batsirai was moving toward the west-northwest at 11 m.p.h. (17 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 963 mb.

Tropical Cyclone Batsirai continued to intensify on Sunday morning. A small circular eye was present at the center of Batsirai’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Batsirai. Storms near the core of the circulation generated upper level divergence that pumped mass away from the tropical cyclone.

The circulation around Tropical Cyclone Batsirai was still small. Winds to hurricane/typhoon force extended out 35 miles (55 km) from the center of Batsirai. Winds to tropical storm force extended out 70 miles (110 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Batsirai was 19.2. The Hurricane Size Index (HSI) was 10.7 and the Hurricane Wind Intensity Size Index (HWISI) was 29.9.

Tropical Cyclone Batsirai will move through an environment favorable for intensification during the next 24 hours. Batsirai 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. Tropical Cyclone Batsirai is likely to continue to intensify. Batsirai could strengthen to the equivalent of a major hurricane during the next 24 hours.

Tropical Cyclone Batsirai will move north of a high pressure system over the South Indian Ocean. The high pressure system will steer Batsirai toward the west during the next several days. On its anticipated track the center of Tropical Cyclone Batsirai will pass north of Rodrigues during the next 24 hours. The core of Batsirai will pass north of Rodrigues, but it could still bring gusty winds and locally heavy rain. Tropical Cyclone Batsirai could approach Mauritius and La Reunion in 48 hours. Batsirai could be the equivalent of a major hurricane at that time. Tropical Cyclone Batsirai could also eventually affect Madagascar later next week.

Tropical Cyclone Batsirai Rapidly Intensifies to Equivalent of Hurricane/Typhoon

Tropical Cyclone Batsirai rapidly intensified to the equivalent of a hurricane/typhoon over the South Indian Ocean on Thursday morning. At 7:00 a.m. EST on Thursday the center of Tropical Cyclone Batsirai was located at latitude 17.9°S and longitude 79.7°E which put it about 1090 miles (1760 km) east-northeast of Rodrigues. Batsirai was moving toward the west-southwest at 25 m.p.h. (40 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 968 mb.

Tropical Cyclone Batsirai rapidly intensified from a tropical storm to the equivalent of a Category 2 hurricane on the Saffir-Simpson Scale after it developed over the South Indian Ocean on Wednesday night. A tiny pinhole eye with a diameter of 8 miles (13 km) quickly formed at the center of Batsirai’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. The strongest winds were occurring about 6 miles (10 km) from the center of circulation. Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Batsirai. Storms near the core generated strong upper level divergence that pumped mass away from the tropical cyclone.

The circulation around Tropical Cyclone Batsirai was very small. Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Batsirai. Winds to tropical storm force extended out 50 miles (80 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Batsirai was 17.8. The Hurricane Size Index (HSI) was 8.6 and the Hurricane Wind Intensity Size Index (HWISI) was 24.4.

Tropical Cyclone Batsirai will move through an environment favorable for intensification during the next 24 hours. Batsirai 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. Tropical Cyclone Batsirai could continue to intensify rapidly during the next few hours. However, if the inner end of a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Batsirai to weaken. Since the circulation around Batsirai is very small, if the tropical cyclone moves into a less favorable environment, it could weaken rapidly.

Tropical Cyclone Batsirai will move north of a high pressure system over the South Indian Ocean. The high pressure system will steer Batsirai toward the west during the next few days. On its anticipated track Tropical Cyclone Batsirai could approach Rodrigues, Mauritius, La Reunion and eventually Madagascar next week. Batsirai could be the equivalent of a hurricane/typhoon when it approaches those places.

Typhoon Rai Brings Gusty Winds and Rain to Central Vietnam

Typhoon Rai brought gusty winds and rain to central Vietnam on Sunday. At 10:00 a.m. EST on Sunday the center of Typhoon Rai was located at latitude 15.5°N and longitude 110.8°E which put it about 185 miles (295 km) east-southeast of Da Nang, Vietnam. Rai was moving toward the north at 11 m.p.h. (17 km/h). The maximum sustained wind speed was 120 m.p.h. (195 km/h) and there were wind gusts to 150 m.p.h. (240 km/h). The minimum surface pressure was 951 mb.

Bands in the western side of Typhoon Rai brought gusty winds and locally heavy rain to central Vietnam on Sunday. Although the core of Typhoon Rai was east of Vietnam, the large size of the circulation resulted in rainbands in the western side of the typhoon moving over central Vietnam. The core of Rai’s circulation where the strongest winds were located remained east of the coast of Vietnam.

Typhoon Rai was weakening over the South China Sea on Sunday. An upper level ridge over the Western North Pacific Ocean was producing southerly winds that were blowing toward the top of Rai’s circulation. A surface high pressure system over Asia was producing northeasterly winds in the lower levels of the atmosphere. The combination of southerly winds in the upper levels and northeasterly winds in the lower levels was causing moderate vertical wind shear. In addition, the northeasterly winds in the lower levels were transporting drier air toward Typhoon Rai.

Some of the drier air was wrapping around the southern side of Typhoon Rai. The strongest thunderstorms were occurring in bands in the western half of Rai’s circulation. Bands in the eastern half of the typhoon consisted primarily of showers and lower clouds. A broken ring of thunderstorms surrounded the eye of Typhoon Rai and the strongest winds were occurring in that ring of storms.

Winds to typhoon force extended out 65 miles (105 km) from the center of Typhoon Rai. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Rai was 22.1. The Hurricane Size Index (HSI) was 20.6 and the Hurricane Wind intensity Size Index (HWISI) was 42.7. Rai was capable of causing regional major damage.

Typhoon Rai will move through an environment that will become unfavorable for intensification during the next 36 hours. Rai will move over water where the Sea Surface Temperatures are near 28˚C. However, the upper level ridge and the surface high pressure system will continue to cause moderate vertical wind shear. More dry air will be pulled into Rai’s circulation. Typhoon Rai will continue to weaken during the next 36 hours.

Typhoon Rai will move around the western end of a surface high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Rai toward the north. On its anticipated track the core of Typhoon Rai will remain east of Vietnam. Bands in the western side of Rai’s circulation will continue to produce gusty winds and locally heavy rain along the coast of Vietnam. The center of Rai could be southeast of Hainan in 18 hours.

Typhoon Rai Rapidly Intensifies Back to Equivalent of Cat. 5 Hurricane

Typhoon Rai rapidly intensified back to the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Saturday over the South China Sea. At 4:00 p.m. EST on Saturday the center of Typhoon Rai was located at latitude 12.8°N and longitude 111.9°E which put it about 355 miles (575 km) southeast of Da Nang, Vietnam. Rai was moving toward the west-northwest at 16 m.p.h. (26 km/h). The maximum sustained wind speed was 165 m.p.h. (265 km/h) and there were wind gusts to 200 m.p.h. (320 km/h). The minimum surface pressure was 910 mb.

Typhoon Rai rapidly intensified to the equivalent of a Category 5 hurricane as it moved over the warm water in the South China Sea on Saturday. The diameter of the eye at the center of Rai contracted to 25 miles (40 km) as the typhoon rapidly intensified. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Rai. Storms near the core generated upper level divergence that pumped large quantities of mass away to the west and north of the typhoon. The removal of so much mass allowed the surface pressure to decrease rapidly.

Winds to typhoon force extended out 45 miles (75 km) from the center of Typhoon Rai. Winds to tropical storm force extended out 150 miles (240 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Rai was 36.7. The Hurricane Size Index (HSI) was 19.6 and the Hurricane Wind intensity Size Index (HWISI) was 56.3. Rai was capable of causing regional catastrophic damage. Typhoon Rai was stronger than it was when it hit the southern Philippines.

Typhoon Rai will move through an environment that will become unfavorable for intensification during the next 36 hours. Rai will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the western end of an upper level ridge over the Western North Pacific Ocean. The ridge will produce southerly winds that will blow toward the top of Typhoon Rai’s circulation. A surface high pressure system over Asia will produce northeasterly winds in the lower levels over the atmosphere. A combination of northeasterly winds in the lower levels and southerly winds in the upper levels will cause the vertical wind shear to increase. The northeasterly winds in the lower levels will also transport drier air toward the northwestern part of Rai’s circulation. Stronger vertical wind shear and drier air will cause Typhoon Rai to weaken during the next 36 hours. If the inner end of a rainband wraps around the existing eye and eyewall, then an eyewall replacement cycle could cause Rai to weaken more rapidly.

Typhoon Rai will move around the western end of a surface high pressure system over the Western North Pacific Ocean during the next 24 hours. The high pressure system will steer Rai toward the north during the next 24 hours. On its anticipated track Typhoon Rai is forecast to turn toward the north before the center of Rai reaches the coast of Vietnam. Rainbands on the western side of Typhoon Rai could bring gusty winds and locally heavy rain to the central coast of Vietnam within 18 hours.

Typhoon Rai Strengthens over South China Sea

Typhoon Rai strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale over the South China Sea on Saturday morning. At 10:00 a.m. EST on Saturday the center of Typhoon Rai was located at latitude 12.2°N and longitude 113.0°E which put it about 450 miles (725 km) southeast of Da Nang, Vietnam. Rai was moving toward the west-northwest at 17 m.p.h. (28 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 942 mb.

Typhoon Rai strengthened to the equivalent of a Category 4 hurricane as it moved over the warm water in the South China Sea on Saturday morning. An eye with a diameter of 30 miles (50 km) was at the center of Rai’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Rai. Storms near the core generated upper level divergence that pumped mass away to the west and north of the typhoon.

Winds to typhoon force extended out 35 miles (55 km) from the center of Typhoon Rai. Winds to tropical storm force extended out 170 miles (275 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Rai was 25.1. The Hurricane Size Index (HSI) was 14.3 and the Hurricane Wind intensity Size Index (HWISI) was 39.4. Rai was capable of causing regional severe damage.

Typhoon Rai will move through an environment that will become unfavorable for intensification during the next 48 hours. Rai will move over water where the Sea Surface Temperatures are near 28˚C. It will move under the southern side of an upper level ridge over the Western North Pacific Ocean. The ridge will produce southeasterly winds that will blow toward the top of Typhoon Rai’s circulation. A surface high pressure system over Asia will produce northeasterly winds in the lower levels over the atmosphere. A combination of northeasterly winds in the lower levels and southeasterly winds in the upper levels will cause the vertical wind shear to increase. The northeasterly winds in the lower levels will also transport drier air toward the northwestern part of Rai’s circulation. Stronger vertical wind shear and drier air will cause Typhoon Rai to weaken during the weekend.

Typhoon Rai will move around the western end of a surface high pressure system over the Western North Pacific Ocean during the next 36 hours. The high pressure system will steer Rai toward the north during the next 36 hours. On its anticipated track Typhoon Rai is forecast to turn toward the north before the center of Rai reaches the coast of Vietnam. Rainbands on the western side of Typhoon Rai could bring gusty winds and locally heavy rain to the central coast of Vietnam in 24 hours.

Typhoon Rai Moves over South China Sea

Typhoon Rai moved over the South China Sea on Friday. At 4:00 p.m. EST on Friday the center of Typhoon Rai was located at latitude 10.9°N and longitude 116.6°E which put it about 175 miles (285 km) west-northwest of Puerto Princesa, Philippines. Rai was moving toward the west-northwest at 14 m.p.h. (22 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. (230 km/h). The minimum surface pressure was 956 mb.

Typhoon Rai strengthened back to the equivalent of a major hurricane after it moved across Palawan and over the South China Sea. An eye with a diameter of 30 miles (50 km) developed at the center of Rai’s circulation. The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the core of Typhoon Rai. Storms near the core generated upper level divergence that pumped mass away to the west and north of the typhoon.

Winds to typhoon force extended out 40 miles (65 km) from the center of Typhoon Rai. Winds to tropical storm force extended out 165 miles (270 km) from the center of circulation. The Hurricane Intensity Index (HII) for Typhoon Rai was 20.6. The Hurricane Size Index (HSI) was 16.4 and the Hurricane Wind intensity Size Index (HWISI) was 37.0. Rai was capable of causing regional major damage.

Typhoon Rai will move through an environment favorable for intensification during the next 24 hours. Rai will move over water where the Sea Surface Temperatures are near 30˚C. It will move under the southern side of an upper level ridge over the Western North Pacific Ocean. The ridge will produce easterly winds that will blow toward the top of Typhoon Rai’s circulation. Those winds will cause some vertical wind shear but the wind shear will be too small to prevent intensification. Typhoon Rai could strengthen again during the next 24 hours.

Typhoon Rai will move south of a surface high pressure system over the Western North Pacific Ocean during the next day or so. The high pressure system will steer Rai toward the west-northwest during the next 24 hours. Rai will move more toward the northwest when it reaches the western end of the high pressure system. On its anticipated track Typhoon Rai could approach the coast of Vietnam in 36 hours.