Tag Archives: HWISI

Tropical Cyclone Idai Rapidly Intensifies Into Equivalent of Hurricane/Typhoon

Tropical Cyclone Idai rapidly intensified into the equivalent of a hurricane/typhoon over the Mozambique Channel on Sunday.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Idai was located at latitude 17.4°S and longitude 43.2°E which put it about 75 miles (120 km) northwest of Maintirano, Madagascar.  Idai was moving toward the south at 1 m.p.h. (2 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (205 km/h).  The minimum surface pressure was 958 mb.

Tropical Cyclone Idai intensified rapidly on Sunday.  An eye was apparent on satellite imagery,  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of Idai.  Storms near the core were generating upper level divergence which was pumping mass away from the tropical cyclone.  Winds to hurricane/typhoon force extended out about 25 miles (40 km) from the center of circulation.  Winds to tropical storm force extended out about 100 miles (160 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Idai was 17.8.  The Hurricane Size Index (HSI) was 10.7 and the Hurricane Wind Intensity Size Index (HWISI) was 28.5.

Tropical Cyclone Idai will continue to move through an environment favorable for intensification during the next day or two,  Idai will move over water where the Sea Surface Temperature is near 30°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Idai could intensify into the equivalent of a major hurricane during the next 24 hours.

Tropical Cyclone Idai will move around the eastern end of a subtropical ridge over southern Africa. The ridge will steer Idai toward the west during the next several days.  On its anticipated track Tropical Idai could approach the coast of Mozambique in about four days.  Idai could be the equivalent of a major hurricane at that time.

Tropical Cyclone Haleh Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Haleh strengthened into the equivalent of a major hurricane on Monday.  At 10:00 a.m. EST on Monday the center of Tropical Cyclone Haleh was centered at latitude 18.9°S and longitude 72.3°E which put it about 800 miles (1290 km) south of Diego Garcia.  Haleh was moving toward the south-southwest at 10 m.p.h. (16 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 948 mb.

Tropical Cyclone Haley rapidly intensified into the equivalent of a major hurricane during the past 24 hours.  A circular eye was clearly evident on satellite imagery.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Storms near the core of the circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.  Bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Haleh.  The strongest bands were in the southern half of the circulation.  Bands in the northern half of the circulation consisted primarily of showers and lower clouds.

Winds to hurricane/typhoon force extended out about 50 miles (80 km) from the center of Tropical Cyclone Haleh.  Winds to tropical storm force extended out about 210 miles (330 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Haleh was 22.1.  The Hurricane Size Index (HSI) was 16.0 and the Hurricane Wind Intensity Size Index (HWISI) was 38.1.

Tropical Cyclone Haleh will move through an environment favorable for intensification during the next 24 hours.  Haleh will move over water where the Sea Surface Temperature is near 29°C.  It will move through a region where the upper level winds will be weak and there will be little vertical wind shear.  Tropical Cyclone Haleh could intensify during the next day or so.  Eventually, Haleh will move over cooler water and it will start to weaken when that occurs.

Tropical Cyclone Haleh will move around the western end of a subtropical ridge over the South Indian Ocean.  The ridge will steer Haleh toward the south-southwest.  On its anticipated track Tropical Cyclone Haleh is forecast to remain well to the southeast of Mauritius and La Reunion.

Typhoon Wutip Strengthens to Equivalent of a Category 5 Hurricane

Typhoon Wutip strengthened into the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale on Monday.  At 5:00 a.m. EST on Monday the center of Typhoon Wutip was located at latitude 14.0°N and longitude 140.1°E which put it about 300 miles (480 km) west-northwest of Guam.  Wutip was moving toward the north-northwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km.h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 929 mb.

Typhoon Wutip completed an eyewall replacement cycle on Sunday and then it rapidly intensified into the equivalent of a Category 5 hurricane.  The inner eyewall dissipated completely and the outer eyewall contracted around a circular, symmetrical eye.  A ring of strong thunderstorms surrounded the new eye and the strongest winds were occurring in that ring of storms.  Storms near the core of Typhoon Wutip were generating strong upper level divergence which was pumping mass away from the typhoon.  Bands of showers and thunderstorms were revolving around the core of Wutip.

Winds to typhoon force extended out about 45 miles (75 km) from the center of Typhoon Wutip.  Winds to tropical storm force extended out about 160 miles (260 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Wutip was 35.0.  The Hurricane Size Index (HSI) was 16.6 and the Hurricane Wind Intensity Size Index (HWISI) was 51.6.

Typhoon Wutip will remain in an environment capable of supporting a strong typhoon for another 12 to 24 hours.  Wutip will move over water where the Sea Surface Temperature is near 28°C.  It will move through a region where the upper level winds are weak and there will be little vertical wind shear.  A band of stronger westerly winds north of the Philippines will approach Typhoon Wutip in another day or so.  Those winds will cause the vertical wind shear to increase and the increased shear will cause Wutip to weaken.

Typhoon Wutip will move southwest of a subtropical ridge over the Western North Pacific Ocean.  The ridge is forecast to steer Wutip in a west-northwesterly direction.  On its forecast track Typhoon Wutip will gradually move farther away from the Northern Marianas.

Typhoon Wutip Strengthens to Equivalent of a Major Hurricane South of Guam

Typhoon Wutip strengthened into the equivalent of a major hurricane south of Guam on Friday.  At 10:00 a.m. EST on Friday the center of Typhoon Wutip was located at latitude 10.1°N and longitude 144.7°E which put it about 240 miles (385 km) south of Guam.  Wutip was moving toward the northwest at 15 m.p.h. (24 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 949 mb.

Tropical Storm Warnings were in effect for Guam, Rota and Faraulep.  Tropical Storm Watches have been issued for Tinian, Saipan, Agrihan and Pagan.

Typhoon Wutip was a very well organized tropical cyclone.  A small eye was at the center of 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 Wutip.  Storms near the core were generating upper level divergence which was pumping mass away from the typhoon.

Typhoon Wutip had a large circulation.  Winds to typhoon force extended out about 45 miles (75 km) from the center of circulation.  Winds to tropical storm force extended out about 185 miles (295 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Wutip was 22.1.  The Hurricane Size Index (HSI) was 17.3 and The Hurricane Wind Intensity Size Index (HWISI) was 39.4.  Typhoon Wutip was capable of causing major damage.

Typhoon Wutip may be near its peak intensity.  Wutip will move over water where the Sea Surface Temperature is near 29°C.  So, there is enough energy in the upper ocean to support a strong typhoon.  Typhoon Wutip has been in an area where the upper level winds were weak and there was little vertical wind shear.  The shear will remain small for another 12 to 24 hours.  Then an upper level trough will approach Typhoon Wutip from the west in a day or so.  The trough will bring southwesterly winds and the vertical wind shear will increase.  Wutip will start to weaken when the shear increases.

Typhoon Wutip will move around the western end of a subtropical ridge over the Western North Pacific Ocean.  Wutip will gradually turn more toward the north while it moves around the end of the ridge.  On its anticipated track the core of Typhoon Wutip will pass west of Guam and the Northern Marianas.  Wutip could bring winds to tropical storm force to Guam and some of the other islands, which is why the warnings and watches were issued.

Tropical Cyclone Gelena Brings Wind and Rain to Rodrigues

Tropical Cyclone Gelena brought wind and rain to Rodrigues on Saturday.  At 10:00 p.m. EST on Saturday the center of Tropical Cyclone Gelena was located at latitude 20.5°S and longitude 63.7°E which put it about 55 miles (90 km) southeast of Rodrigues, Mauritius.  Gelena was moving toward the east-southeast at 18 m.p.h. (29 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 959 mb.

Tropical Cyclone Gelena was the equivalent of a major hurricane when it moved past Rodrigues.  Winds to hurricane/typhoon force extended out about 40 miles (65 km) from the center of circulation.  Winds to tropical storm force extended out about 150 miles (240 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Gelena was 20.6.  The Hurricane Size Index (HSI) was 15.9 and the Hurricane Wind Intensity Size Index (HWISI) was 36.5.

The northeastern part of the eyewall of Tropical Cyclone Gelena appeared to cross Rodrigues.  Winds to hurricane/typhoon force may have occurred when that part of the eyewall moved over the island.  Winds to tropical storm force will continue for a few more hours until Gelena moves farther away from Rodrigues.  Conditions on Rodrigues should gradually improve on Sunday while Tropical Cyclone Gelena moves farther away.  Gelena will weaken as it moves over colder water.

Elsewhere over South Indian Ocean, Tropical Cyclone Funani made a transition to an extratropical cyclone.  At 4:00 p.m. EST the center of Tropical Cyclone Funani was located at latitude 31.9°S and longitude 77.4°E which put it about 1390 miles (2245 km) southeast of Mauritius.  Funani was moving toward the southeast at 28 m.p.h. (45 km/h).  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 996 mb.

Tropical Cyclone Gelena Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Gelena strengthened into the equivalent of a major hurricane on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Gelena was located at latitude 16.8°S and longitude 56.9°E which put it about 265 miles (425 km) north of Port Louis, Mauritius.  Gelena was moving toward the southeast at 15 m.p.h. (24 km/h).  The maximum sustained wind speed was 125 m.p.h. (205 km/h) and there were wind gusts to 155 m.p.h. (205 km/h).  The minimum surface pressure was 953 mb.

The circulation around Tropical Cyclone Gelena strengthened and grew larger on Friday.  An eye appeared intermittently at the center of Gelena on satellite imagery.  A ring of strong thunderstorms surrounded the eye and the strongest winds were occurring in the ring of storms.  More bands of showers and thunderstorms were revolving around the core of the circulation.  Winds to hurricane/typhoon force extended out about 50 miles (80 km) from the center of circulation.  Winds to tropical storm force extended out about 175 miles (280 km) from the center.

The Hurricane Intensity Index (HII) for Tropical Cyclone Gelena was 23.6.  The Hurricane Size Index (HSI) was 17.3 and the Hurricane Wind Intensity Size Index (HWISI) was 40.9.  Those indices indicated that tropical Cyclone Gelena was capable of causing major regional damage.

Tropical Cyclone Gelena will move through an environment somewhat favorable for intensification for another 12 to 24 hours.  Gelena will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough near Madagascar will produce westerly winds which are blowing toward the top of Tropical Cyclone Gelena.  Those winds will produce some vertical wind shear and they will inhibit upper level divergence toward the western periphery of Gelena.  The wind shear will inhibit intensification, but Tropical Cyclone Gelena could strengthen on Saturday.

Tropical Cyclone Gelena will move south of a subtropical ridge.  The ridge will steer Gelena in a southeasterly direction.  On its anticipated track Tropical Cyclone Gelena will pass north of Mauritius.  However, Gelena could approach Rodrigues within 36 hours.  Tropical Cyclone Gelena could bring strong winds and heavy rain to Rodrigues.

Elsewhere over the southern Indian Ocean, Tropical Cyclone Funani was speeding toward colder water.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Funani was located at latitude 26.3°S and longitude 73.4°E which put it about 805 miles (1295 km) east-southeast of Rodrigues.  Funani was moving toward the southeast at 28 m.p.h. (45 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. (170 km/h).  The minimum surface pressure was 977 mb.

Powerful Tropical Cyclone Cilida Strengthens to Equivalent of Cat. 4 Hurricane

Powerful Tropical Cyclone Cilida strengthened to the equivalent of a Category 4 hurricane on the Saffir-Simpson Scale on Friday.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Cilida was located at latitude 15.9°S and longitude 57.8°E which put it about 310 miles (505 km) north of Port Louis, Mauritius.  Cilida was moving toward the south at 6 m.p.h. (10 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 931 mb.

The circulation of Tropical Cyclone Cilida was very well organized.  A circular eye was at the center of circulation.  The eye was surrounded by a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms.  Several bands of showers and thunderstorms were revolving around the core of Tropical Cyclone Cilida.  Storms around the core were generating strong upper level divergence which was pumping mass away from the tropical cyclone.

The circulation around Tropical Cyclone Cilida was relatively small.  Winds to hurricane/typhoon force extended out about 35 miles (55 km) from the center of circulation.  Winds to tropical storm force only extended out about 95 miles (155 km) from the center.  The Hurricane Intensity Index (HII) for Tropical Cyclone Cilida was 31.6.  The Hurricane Size Index (HSI) was 11.0 and the Hurricane Wind Intensity Size Index (HWISI) was 42.6.

Tropical Cyclone Cilida may have peaked in intensity, but it will move through an environment capable of supporting a strong tropical cyclone for another 24 to 36 hours.  Cilida will move over water where the Sea Surface Temperature is near 28°C for about another 24 hours.  Then it will start to move over colder waters.  Tropical Cyclone Cilida will move toward the upper level westerly winds in the middle latitudes and the vertical wind shear will increase in about 36 hours.  When Cilida moves over colder water and under stronger upper level winds, it will weaken more quickly.

Tropical Cyclone Cilida is moving around the western end of a subtropical ridge over the South Indian Ocean.  The ridge will start to steer Cilida toward the southeast on Saturday.  On its anticipated track, the center of Tropical Cyclone Cilida could be a little northeast of Mauritius in about 24 hours.  It will still be a powerful tropical cyclone at that time.

Elsewhere over the South Indian Ocean, Tropical Cyclone Kenanga continued to weaken well to the southeast of Diego Garcia.  At 4:00 p.m. EST on Friday the center of Tropical Cyclone Kenanga was located at latitude 16.3°S and longitude 78.5°E which put it about 760 miles (1225 km) southeast of Diego Garcia.  Kenanga was moving toward the west at 7 m.p.h. (11 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 982 mb.

Typhoon Yutu Brings Wind and Rain to Luzon

Typhoon Yutu brought wind and rain to Luzon on Monday.  At 5:00 p.m. EDT on Monday the center of Typhoon Yutu was located at latitude 16.8°N and longitude 122.4°E which put it about 45 miles (75 km east of Ilagan, Philippines.  Yutu was moving toward the west at 14 m.p.h. (22 km/h).  The maximum sustained wind speed was 105 m.p.h. (170 km/h) and there were wind gusts to 125 m.p.h. (200 km/h).  The minimum surface pressure was 949 mb.

The center of Typhoon Yutu made landfall near Palanan Point on the northeast coast of Luzon late on Monday.  Yutu had a large circulation.  Winds to typhoon force extended out about 80 miles (130 km) from the center of circulation.  Winds to tropical storm force extended out about 270 miles (435 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Yutu was 17.8.  The Hurricane Size Index (HSI) was 25.5 and the Hurricane Wind Intensity Size Index (HWISI) was 43.3.  Typhoon Yutu is capable of causing widespread serious damage.

Typhoon Yutu could cause a storm surge of up to 10 feet (3 meters) on the northeast coast of Luzon.  It will also produce destructive winds as it moves across northern Luzon.  Yutu will move westward across Luzon.  It will move into the South China Sea south of Vigan, Philippines.  Typhoon Yutu will drop very heavy rain over parts of northern Luzon and flash flooding will be very likely.  Rapid runoff into the Cagayan River could cause it to flood.

Typhoon Yutu will move over the Sierra Madre mountains and the Cordillera Central when it moves across northern Luzon.  Those two mountain ranges will disrupt the lower levels of the circulation and Yutu will be weaker when it reaches the South China Sea.  Yutu could still be a typhoon when it moves back over water, but it may weaken to a tropical storm by then.

Typhoon Yutu will move around the western end of a ridge of high pressure over the Western North Pacific Ocean when it reaches the South China Sea.  Yutu will move toward the north when it reaches the western end of the ridge and it could approach China in four or five days.

Powerful Typhoon Yutu Threatens Northern Luzon

Powerful Typhoon Yutu continued to pose a threat to northern Luzon on Saturday.  At 11:00 p.m. EDT on Saturday the center of Typhoon Yutu was located at latitude 18.0°N and longitude 129.6°E which put it about 475 miles (765 km) east of Cape Engano, Philippines.  Yutu was moving toward the west at 12 m.p.h. (19 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 929 mb.

There were minor fluctuations in its intensity on Saturday, but Typhoon Yutu remains a very powerful tropical cyclone.  A circular eye is at the center of circulation.  The eye is surrounded by a ring of strong thunderstorms and the strongest winds are occurring in that ring of storms.  Several bands of showers and thunderstorms are revolving around the core of Typhoon Yutu.  Storms around the core are generating strong upper level divergence which is pumping mass away from the typhoon in all directions.

Typhoon Yutu has a large circulation.  Winds to typhoon force extend out about 75 miles (120 km) from the center of circulation.  Winds to tropical storm force extend out about 250 miles (400 km) from the center.  The Hurricane Intensity Index (HII) for Typhoon Yutu is 31.6.  The Hurricane Size Index (HSI) is 28.3 and the Hurricane Wind Intensity Size Index (HWISI) is 59.9.  Typhoon Yutu is capable of causing wide spread significant damage.

Typhoon Yutu will continue to move south of a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Yutu in a generally westerly direction for another 36 to 48 hours.  On its anticipated track Typhoon Yutu will reach northern Luzon in about 36 to 42 hours.  Yutu will create a storm surge at the coast.  It will cause significant wind damage over northern Luzon.  Yutu will also drop locally heavy rain and cause flash floods over parts of northern Luzon.

Powerful Typhoon Yutu Churns Toward Northern Luzon

Powerful Typhoon Yutu churned toward northern Luzon on Friday.  At 5:00 p.m. EDT on Friday the center of Typhoon Yutu was located at latitude 17.7°N and longitude 135.9°E which put it about 900 miles (1450 km) east of Cape Engano, Philippines.  Yutu was moving toward the west-northwest at 17 m.p.h. (28 km/h).  The maximum sustained wind speed was 160 m.p.h. (260 km/h) and there were wind gusts to 195 m.p.h. (315 km/h).  The minimum surface pressure was 920 mb.

After completing an eyewall replacement cycle Typhoon Yutu strengthened again on Friday.  Yutu is once again the equivalent of a Category 5 hurricane on the Saffir-Simpson Scale.  The eyewall replacement cycle also caused an increase in the size of Typhoon Yutu’s circulation.  Winds to typhoon force extend out about 80 miles (130 km) from the center of circulation.  Winds to tropical storm force extend out about 260 miles (420 km) from the center.  The Hurricane Intensity Index (HII) is 35.0.  The Hurricane Size Index (HSI) is 28.9 and the Hurricane Wind Intensity Size Index (HWISI) is 63.9.

Typhoon Yutu has a large, very well organized circulation and it will remain in an environment capable of supporting a powerful typhoon for several more days.  Yutu will move over water where the Sea Surface Temperature is near 31°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Typhoon Yutu could strengthen a little more during the next 12 to 24 hours.  At some point another rainband is likely to wrap around the existing eye and eyewall, and another eyewall replacement cycle could occur.  If there is another eyewall replacement cycle, then Yutu would weaken, at least temporarily.

Typhoon Yutu will move south of a ridge of high pressure over the Western North Pacific Ocean.  The ridge will steer Yutu in a generally westward direction.  On its anticipated track Typhoon Yutu could reach northern Luzon in about four days.  Yutu is very likely to be a strong typhoon when it approaches Luzon.