Tropical Cyclone Marian continued to spin over the South Indian Ocean southwest of Cocos Island on Tuesday. At 10:00 a.m. EST on Tuesday the center of Tropical Cyclone Marian was located at latitude 18.8°S and longitude 90.0°E which put it about 650 miles (1045 km) southwest of Cocos Island. Marian was moving toward the east-southeast at 3 m.p.h. (5 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 958 mb.
The circulation around Tropical Cyclone Marian remained well organized on Tuesday morning. A circular eye with a diameter of 35 miles (55 km) was present at the center of Marian. The eye was surrounded a ring of strong thunderstorms and the strongest winds were occurring in that ring of storms. Even though the circulation was well organized, satellite images of Tropical Cyclone Marian suggested that it could be starting to weaken. The temperature of the tops of thunderstorms was warming which indicated that those storms were not rising as high in the atmosphere. Microwave satellite imagery depicted breaks forming in the southwestern part of the eyewall of Marian.
Winds to hurricane/typhoon force extended out 65 miles (105 km) from the center of Tropical Cyclone Marian. Winds to tropical storm force extended out 185 miles (295 km) from the center of circulation. The Hurricane Intensity Index (HII) for Tropical Cyclone Marian was 17.8. The Hurricane Size Index (HSI) was 21.6 and the Hurricane Wind Intensity Size Index (HWISI) was 39.4.
Tropical Cyclone Marian will move into an environment that will be less favorable for tropical cyclones during the next few days. Marian will move over water where the Sea Surface Temperatures will be near 27°C. An upper level trough over the South Indian Ocean will approach Tropical Cyclone Marian from the west. The trough will produce northwesterly winds which will blow toward the top of Marian. Those winds will cause more vertical wind shear. A combination of slightly cooler water and more vertical wind shear will cause Tropical Cyclone Marian to weaken during the next several days.
The upper level trough will begin to steer Tropical Cyclone Marian toward the southeast. On its anticipated track Marian will move farther away from Cocos Island. Tropical Cyclone Marian is forecast to remain west of Western Australia during the next five days.