NASA - National Aeronautics and Space Administration

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Feb. 8, 2008

Tropical Cyclone 17S Trudging Through Indian Ocean



Tropical Cyclone 17S is far east of the other two tropical cyclones in the Indian Ocean, but it's holding its own.

On Thursday, February 07, 2008 at 1200 Zulu Time (7:00 a.m. EST), 17S was located near 16.8 degrees south latitude and 105.8 degrees east longitude, about 565 nautical miles west-northwest of Learmonth, Australia. It has tracked south-southeastward at 4 knots (4 mph) recently and had sustained winds near 35 knots (40 mph).

This image of 17S was created on Feb 7 at 6:17 UTC (1:17 a.m. EST) by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite. In the image, the round purple object in the bottom left corner of the image is 17S. Australia is visible to the far east of the storm, and the islands of Indonesia are located to the north of Australia.

This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of Cyclone 17S.

The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red).

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Feb. 8, 2008

Three Cyclones Make for a Very Busy Indian Ocean

There are three tropical cyclones in the Indian Ocean, two are tropical storms, and one is a major hurricane. Tropical Cyclones 16S, 17S and 18S were all active on Feb. 7.

Powerful Category 4 Cyclone Hondo in Indian Ocean

The sixteenth tropical cyclone of the Indian Ocean season, named Hondo (pictured as the tightly wound blue and purple shape in the right of this image) was packing maximum sustained winds of 120 knots (138 mph) with gusts to 145 knots (166 mph) in the open ocean. Hondo is a category four hurricane on the Saffir-Simpson Scale.

On February 7, 2008 at 600 Zulu Time (1:00 a.m. EST), Tropical cyclone Hondo (also known as 16C) was located near 14.7 degrees South latitude and 82.7 degrees East longitude, approximately 745 nautical miles southeast of Diego Garcia. Hondo has tracked east-southeastward at 4 knots (4 mph) over the past six hours.

Diego Garcia is an atoll located in the heart of the Indian Ocean, some 1,000 miles south off Sri Lanka and India's southern coast.

Forecasters at the Joint Typhoon Warning Center forecast that the "system will continue to track southeastward. The storm will maintain intensity through the next 24 hours, then begin to weaken slightly by 48 hours." Hondo is generating waves as high as 32 feet in the open ocean.

Tropical Cyclone 18S a Tropical Storm

Tropical cyclone 18s (no name) was located approximately 770 nautical miles west-southwest of Diego Garcia, or near 12.9 degrees south latitude and 60.7 degrees east longitude. 18S tracked east-southeastward at 11 knots (12 mph) over the past six hours. 18S has maximum sustained winds of 35 knots (40 mph).

The Third Cyclone in the Region

At the same time, Tropical Cyclone 17S (No Name) was located far east from the other, approximately 565 nautical miles west-northwest of Learmonth, Australia, with sustained winds near 35 knots (40 mph). (17S is not shown in this satellite image).

NASA's Satellite Image Spies Two of the Three Cyclones


Click image to enlarge.
This image shows Hondo (tight round shape on the right), and Tropical Cyclone 18S (larger rounded shape left) was created on Feb 7 at 7:53 UTC (2:53 a.m. EST) by data from the Atmospheric Infrared Sounder (AIRS), an instrument that flies aboard NASA's Aqua satellite.

This AIRS image shows the temperature of the cloud tops or the surface of the Earth in cloud-free regions. The lowest temperatures (in purple) are associated with high, cold cloud tops that make up the top of Tropical Cyclones Hondo and 18S.

The infrared signal of the AIRS instrument does not penetrate through clouds. Where there are no clouds the AIRS instrument reads the infrared signal from the surface of the Earth, revealing warmer temperatures (red).

The National Hurricane Center's definition of a Category Four Hurricane includes: Winds 131-155 mph (114-135 knots or 210-249 km/hour). Storm surge generally 13-18 feet above normal. More extensive curtainwall failures with some complete roof structure failures on small residences. Shrubs, trees, and all signs are blown down. Complete destruction of mobile homes. Extensive damage to doors and windows. Low-lying escape routes may be cut by rising water 3-5 hours before arrival of the center of the hurricane. Major damage to lower floors of structures near the shore. Terrain lower than 10 feet above sea level may be flooded requiring massive evacuation of residential areas as far inland as 6 miles (10 kilometers). Image credit: Credit: NASA JPL

Text credit: Rob Gutro, NASA's Goddard Space Flight Center