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Tropical Cyclone Herman Weakens Southeast of Cocos Islands

Tropical Cyclone Herman weakened over the South Indian Ocean southeast of the Cocos Islands on Saturday. At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Herman was located at latitude 19.9°S and longitude 106.7°E which put it about 865 miles (1395 km) southeast of the Cocos Islands. Herman was moving toward the south-southwest at 5 m.p.h. (8 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 978 mb.

Tropical Cyclone Herman weakened on Saturday. An upper level trough over the South Indian Ocean produced northwesterly winds that blew toward the top of Herman’s circulation. Those winds caused moderate vertical wind shear and the wind shear caused Tropical Cyclone Herman to weaken. An eye was no longer evident on satellite images of Herman. The inner end of a rainband still wrapped around the southern and western sides of the center of Herman’s circulation. The circulation around Tropical Cyclone Herman was small. Winds to hurricane/typhoon force extended out 20 miles (30 km) from the center of Herman. Winds to tropical storm force extended out 60 miles (95 km) from the center of circulation.

Tropical Cyclone Herman will move through an environment that will be unfavorable for intensification during the next 36 hours. Herman will move over water where the Sea Surface Temperatures are near 26˚C. However, the upper level trough over the South Indian Ocean will continue to produce northwesterly winds that will blow toward the top of Herman’s circulation. Those winds will continue to cause moderate vertical wind shear and the wind shear will cause Tropical Cyclone Herman to weaken. Since Herman’s circulation is small, the tropical cyclone could weaken rapidly at times.

Tropical Cyclone Herman will move north of high pressure system over the South Indian Ocean. The high pressure system will steer Herman toward the west during the next 36 hours. On its anticipated track, Tropical Cyclone Herman will remain far to the south of the Cocos Islands.

Tropical Cyclone Herman Strengthens to Equivalent of a Major Hurricane

Tropical Cyclone Herman strengthened to the equivalent of a major hurricane over the South Indian Ocean northwest of Australia during Thursday night. At 11:00 a.m. EDT on Friday the center of Tropical Cyclone Herman was located at latitude 18.0°S and longitude 106.8°E which put it about 780 miles (1260 km) east-southeast of Cocos Islands. Herman was moving toward the southeast at 6 m.p.h. (10 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 947 mb.

Tropical Cyclone Herman strengthened to the equivalent of a major hurricane over the South Indian Ocean during Thursday night. A small circular eye was present at the center of Herman’s circulation. 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 center of Tropical Cyclone Herman. Storms near the center generated upper level divergence that pumped mass away to the southeast of the tropical cyclone.

The circulation around Tropical Cyclone Herman was small. Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Herman. Winds to tropical storm force extended out 60 miles (95 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Herman was 23.6. The Hurricane Size Index (HSI) was 8.6 and the Hurricane Wind Intensity Size Index (HWISI) was 32.2. Tropical Cyclone Herman was similar in size and intensity to Hurricane Dennis when Dennis made landfall in northwest Florida in 2005.

Tropical Cyclone Herman will move through an environment that will become unfavorable for intensification during the next 24 hours. Herman will move over water where the Sea Surface Temperatures are near 28˚C. However, an upper level trough will approach Tropical Cyclone Herman from the west. The upper level trough will produce northwesterly winds that will get stronger during the next 24 hours. Those stronger winds will blow toward the top of Herman’s circulation and the vertical wind shear will increase. More vertical wind shear will cause Tropical Cyclone Herman to weaken. Since Herman’s circulation is small, the tropical cyclone could weaken rapidly when the wind shear increases.

The upper level trough will steer Tropical Cyclone Herman toward the south-southeast during the next 24 hours. On its anticipated track Tropical Cyclone Herman will move farther away from Cocos Islands. When the stronger vertical wind shear causes Herman to weaken, it will be steered by the winds closer to the surface. Those winds will steer Tropical Cyclone Herman toward the west during the weekend.

Tropical Cyclone Herman Rapidly Intensifies to Equivalent of Hurricane/Typhoon

Tropical Cyclone Herman rapidly intensified to the equivalent of a hurricane/typhoon over the South Indian Ocean northwest of Australia on Thursday. At 5:00 p.m. EDT on Thursday the center of Tropical Cyclone Herman was located at latitude 16.5°S and longitude 106.0°E which put it about 665 miles (1070 km) east-southeast of Cocos Islands. Herman was moving toward the south-southeast at 9 m.p.h. (15 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 959 mb.

Tropical Cyclone Herman rapidly intensified to nearly the equivalent of a major hurricane over the South Indian Ocean on Thursday. A small circular eye was present at the center of Herman’s circulation. 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 center of Tropical Cyclone Herman. Storms near the center generated upper level divergence that pumped mass away to the southeast of the tropical cyclone.

The circulation around Tropical Cyclone Herman was small. Winds to hurricane/typhoon force extended out 25 miles (40 km) from the center of Herman. Winds to tropical storm force extended out 80 miles (130 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Herman was 19.2. The Hurricane Size Index (HSI) was 9.4 and the Hurricane Wind Intensity Size Index (HWISI) was 28.6. Tropical Cyclone Herman was similar in size and intensity to Hurricane Zeta when Zeta made landfall in Louisiana in 2020.

Tropical Cyclone Herman will move through an environment that will become unfavorable for intensification during the next 24 hours. Herman will move over water where the Sea Surface Temperatures are near 28˚C. However, an upper level trough will approach Tropical Cyclone Herman from the west. The upper level trough will produce northwesterly winds that will get stronger during the next 24 hours. Those stronger winds will blow toward the top of Herman’s circulation and the vertical wind shear will increase. More vertical wind shear will cause Tropical Cyclone Herman to weaken.

The upper level trough will steer Tropical Cyclone Herman toward the south-southeast during the next 24 hours. On its anticipated track Tropical Cyclone Herman will move farther away from Cocos Islands. When the stronger vertical wind shear causes Herman to weaken, it will be steered by the winds closer to the surface. Those winds will steer Tropical Cyclone Herman toward the west during the weekend.

Tropical Cyclone Herman Strengthens Northwest of Australia

Tropical Cyclone Herman strengthened over the South Indian Ocean northwest of Australia during Wednesday night. At 5:00 a.m. EDT on Thursday the center of Tropical Cyclone Herman was located at latitude 15.5°S and longitude 105.1°E which put it about 570 miles (920 km) east-southeast of Cocos Islands. Herman was moving toward the southeast at 10 m.p.h. (16 km/h). The maximum sustained wind speed was 70 m.p.h. (110 km/h) and there were wind gusts to 85 m.p.h. (135 km/h). The minimum surface pressure was 985 mb.

Tropical Cyclone Herman strengthened over the South Indian Ocean northwest of Australia during the past 24 hours. The inner end of a rainband wrapped completely around the center of Herman’s circulation. A small circular eye formed at the center of circulation. A ring of thunderstorms surrounded the eye and the strongest winds were occurring in that ring of storms. Bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Herman. Storms near the center generated upper level divergence that pumped mass away to the southeast of the tropical cyclone. Winds to tropical storm force extended out 65 miles (105 km) from the center of Herman’s circulation.

Tropical Cyclone Herman will move through an environment that will become unfavorable for intensification during the next 24 hours. Herman will move over water where the Sea Surface Temperatures are near 28˚C. However, an upper level trough will approach Tropical Cyclone Herman from the west. The upper level trough will produce northwesterly winds that will get stronger during the next 24 hours. Those stronger winds will blow toward the top of Herman’s circulation and the vertical wind shear will increase. More vertical wind shear will cause Tropical Cyclone Herman to weaken.

The upper level trough will steer Tropical Cyclone Herman toward the southeast during the next 24 hours. On its anticipated track Tropical Cyclone Herman will move farther away from Cocos Islands. When the stronger vertical wind shear causes Herman to weaken, it will be steered by the winds closer to the surface. Those winds will steer Tropical Cyclone Herman toward the west during the end of the week and the weekend.

Tropical Cyclone Herman Forms Northwest of Australia

Tropical Cyclone Herman formed over the South Indian Ocean northwest of Australia on Wednesday morning. At 5:00 a.m. EDT on Wednesday the center of Tropical Cyclone Herman was located at latitude 13.9°S and longitude 101.5°E which put it about 300 miles (480 km) east-southeast of Cocos Islands. Herman was moving toward the southwest at 12 m.p.h. (19 km/h). The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h). The minimum surface pressure was 997 mb.

An area of low pressure over the South Indian Ocean east-southeast of Cocos Islands strengthened on Wednesday morning and the the Australian Bureau of Meteorology designated the system as Tropical Cyclone Herman. The inner end of a rainband wrapped around the western side of the center of Herman’s circulation. The strongest winds were occurring in the part of the band west of the center. Other bands of showers and thunderstorms were revolving around the center of Tropical Cyclone Herman. Storms near the center of circulation generated upper level divergence that pumped mass away from the tropical cyclone. Winds to tropical storm force extended out 160 miles (260 km) from the center of Herman’s circulation.

Tropical Cyclone Herman will move through an environment favorable for intensification during the next 24 hours. Herman 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 eastern part of the South Indian Ocean. The ridge will produce northerly winds that will blow toward the top of Herman’s circulation. Those winds will cause some vertical wind shear, but the wind shear will not be enough to prevent intensification. Tropical Cyclone Herman is likely to strengthen during the next 24 hours. An upper level trough will approach Herman from the west on Thursday. The trough will cause the upper level winds to get stronger and the vertical wind shear will increase. More vertical wind shear will cause Tropical Cyclone Herman to weaken.

Tropical Cyclone Herman will move around the southwestern part of a high pressure system over the eastern South Indian Ocean. The high pressure system will steer Herman toward the southeast during the next 24 hours. On its anticipated track Tropical Cyclone Herman will move away from Cocos Islands. When Herman weakens later this week, it will be steered by the winds closer to the surface. Those winds will steer Tropical Cyclone Herman toward the west during the end of the week and the weekend.

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.

Tropical Cyclone Haleh Develops Southeast of Diego Garcia

Tropical Cyclone Haleh developed southeast of Diego Garcia on Saturday.  At 4:00 p.m. EST on Saturday the center of Tropical Cyclone Haleh was located at latitude 13.5°S and longitude 73.9°E which put it about 435 miles (700 km) south-southeast of Diego Garcia.  Haleh was moving toward the south-southwest at 8 m.p.h. (13 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 981 mb.

The circulation around Tropical Cyclone Haleh organized quickly on Saturday.  An inner rainband wrapped around the southern and western sides of the center of circulation.  Other bands of showers and thunderstorms were revolving around the core of Haleh.  The strongest rainbands were occurring in the eastern half of the circulation.  Rainbands in the western half of the circulation consisted mostly of showers and lower clouds.  Storms near the core of Haleh were generating upper level divergence which was pumping mass away to the southeast of the tropical cyclone.  Winds to tropical storm force extended out about 160 miles (260 km) from the center of circulation.

Tropical Cyclone Haleh will move through an environment favorable for intensification during the next several days.  Haleh will move over water where the Sea Surface Temperature is near 29°C.  An upper level trough to the west of Tropical Cyclone Haleh will produce northwesterly winds which will blow toward the top of the circulation.  Those winds will cause some vertical wind shear, but the shear will not be strong enough to prevent intensification.  Tropical Cyclone Haleh is forecast to intensify into the equivalent of a hurricane/typhoon.

Tropical Cyclone Haleh will move around the northwestern part of a subtropical ridge over the South Indian Ocean.  The ridge will steer Haleh toward the southwest during the next few days.  On its anticipated track Tropical Cyclone Haleh will remain well to the south of Diego Garcia.

Tropical Cyclone Frances Intensifies Into Equivalent of a Hurricane

Tropical Cyclone Frances intensified into the equivalent of a hurricane/typhoon on Friday as it moved northwest of Australia.  At 5:00 p.m. EDT on Friday the center of Tropical Cyclone Frances was located at latitude 12.6°S and longitude 124.1°E which put it about 200 miles (325 km) north of Kuri Bay, Australia.  Frances was moving toward the west-southwest at 9 m.p.h. (14 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 981 mb.

Tropical Cyclone Frances intensified into the equivalent of a hurricane/typhoon when it moved through a favorable environment.  Frances moved over water where the Sea Surface Temperature (SST) was near 30°C and the upper level winds were weak.  A primary rainband wrapped almost entirely around the center of circulation and an eyelike feature seemed to be indicated on some satellite imagery.  Thunderstorms around the eye generated upper level divergence which pumped out mass and the circulation assumed a more symmetrical circulation.  Other bands of showers and thunderstorms formed in the outer portions of the circulation.

Tropical Cyclone Frances may have reached its peak intensity.  Frances will continue to move over water where the SST is near 30°C.  However, it is about to move near the western end of an upper level ridge where there are stronger northerly winds.  Those stronger winds will create much more vertical wind shear and Tropical Cyclone Frances is likely to weaken during the next several days.

A subtropical ridge to the east of Frances is steering the tropical cyclone toward the west-southwest and that general motion is forecast to continue for the next several days.  On its anticipated track Tropical Cyclone Frances poses no threat to Western Australia, although it could cause increased wave action along the coast.

Tropical Cyclone Frances Develops North of Western Australia

An area of low pressure northwest of Western Australia developed into Tropical Cyclone Frances on Thursday.  At 10:00 a.m. EDT on Thursday the center of Tropical Cyclone Frances was located at latitude 11.0°S and longitude 128.3°E which put it about 255 miles (410 km) north-northeast of Kalumburu, Australia.  Frances was moving toward the west-southwest at 12 m.p.h. (19 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. (110 km/h).  The minimum surface pressure was 997 mb.

The organization of Tropical Cyclone Frances improved significantly during the past 24 hours.  A well organized center of circulation developed at the surface.  A primary rainband wrapped about two-thirds of the way around the southern and western sides of the center.  Additional bands of showers and thunderstorms formed in the outer portions of the circulation.  Thunderstorms near the core of the circulation generated upper level divergence which was pumping mass away to the south of the tropical cyclone.  Frances is a fairly small tropical cyclone and winds to tropical storm force only extend out about 100 miles (160 km) from the center.

Tropical Cyclone Frances will move through an environment that will be favorable for intensification during the next 24 to 36 hours.  Frances will move over water where the Sea Surface Temperature is near 30°C while is moves across the Timor Sea.  An upper level ridge east of Tropical Cyclone Frances is producing northeasterly winds which are blowing toward the top of the circulation.  Vertical wind shear may be the reason that the primary rainband wrapped around the southern and western sides of the center.  However, the vertical shear does not appear to be strong enough to significantly affect the upper level divergence.  Frances is likely to intensify during the next day or so.  Eventually, Tropical Cyclone Frances will move into an area where there are strong upper level northwesterly winds.  A significant increase in vertical wind shear should weaken Frances when that occurs.

A subtropical ridge to the east of Frances is steering the tropical cyclone toward the west-southwest.  A general motion toward the west-southwest is expected to continue during the next few days.  On its anticipated track the center of Tropical Cyclone Frances is forecast to stay north of the coast of Western Australia.  However, any southward deviation of the track could bring stronger winds closer to the coast.