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Tropical Cyclone Anais (South Indian Ocean)
10.17.12
 
Tropical Cyclone Anais

The MODIS instrument aboard NASA's Terra satellite captured this visible image of Tropical Cyclone Anais off Madagascar on Oct. 17 at 0640 UTC (2:40 a.m. EDT). The colorful area located east of the center are phytoplankton. Credit: NASA/Goddard/MODIS Rapid Response Team
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NASA Sees Tropical Cyclone Anais and Phytoplankton Near Madagascar

Tropical Cyclone Anais continues to move toward Madagascar and a NASA satellite image picked up a splotch of color east of the storm's center, as a result of phytoplankton on the ocean's surface.

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Aqua satellite captured a visible image of Tropical Cyclone Anais off Madagascar on Oct. 17 at 0640 UTC (2:40 a.m. EDT). Wind shear has taken its toll on the cyclone, pushing the showers and thunderstorms to the southeast of the center. The imagery also showed a colorful area of phytoplankton located east of the center.

On Oct. 17 at 0300 UTC (11 p.m. EDT, Oct. 16) Anais was 405 nautical miles north-northeast of La Reunion, and has been moving to the west at 12 knots (13.8 mph/22.2 kph). Anais' maximum sustained winds tumbled to 45 knots (51.7 mph/81.3 kph)because of adverse environmental conditions.

Wind shear is taking its toll on Anais, and it is expected to dissipate well to the north of La Reunion sometime on Oct. 18, 2012.

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



Oct. 16, 2012

NASA's TRMM satellite's view of Tropical Storm Anais on Oct. 16 at 2:54 a.m. EDT. › View larger image
When NASA's TRMM satellite passed over Tropical Storm Anais on Oct. 16 at 0654 UTC (2:54 a.m. EDT), light to moderate rainfall (green and blue) was occurring southeast of the center and falling at a rate between .78 to 1.57 inches/20 to 40 mm per hour. There no areas of heavy rainfall, indicating that the storm had weakened since the previous day. Credit: SSAI/NASA, Hal Pierce
NASA Sees Rainfall Pushed Away from Tropical Storm Anais' Center

Satellite imagery from NASA's TRMM satellite showed that wind shear is pushing the bulk of rainfall away from the center of Tropical Storm Anais.

When NASA's Tropical Rainfall Measuring Mission (TRMM) satellite passed over Tropical Storm Anais on Oct. 16 at 0654 UTC (2:54 a.m. EDT), light to moderate rainfall was occurring southeast of the center and falling at a rate between .78 to 1.57 inches/20 to 40 mm per hour. The displacement of rainfall from around the storm's center to the southeast indicates moderate to strong northwesterly wind shear.There no areas of heavy rainfall, indicating that the storm had weakened since the previous day.

Forecasters at the Joint Typhoon Warning Center noted "the TRMM image depicts tightly-curved, shallow convective (thunderstorm) banding wrapping into a well-defined center with deep convective banding limited to the south quadrant."

Tropical Storm Anais had maximum sustained winds near 55 knots (63.2 mph/102 kph) on Oct. 16 at 1500 UTC (11 a.m. EDT). Anais was located near 14.4 South and 59.8 East, about 500 nautical miles (575 miles/926 km) north-northeast of La Reunion and moving toward the west-southwest at 9 knots (10.3 mph/16.6 kph).

Anais is forecast to continue tracking to the west-southwest toward Madagascar, while weakening.

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



Oct. 15, 2012

MODIS captured this visible image of Tropical Cyclone Anais off Madagascar on Oct. 15. › View larger image
The MODIS instrument aboard NASA's Aqua satellite captured this visible image of Tropical Cyclone Anais off Madagascar on Oct. 15 at 0940 UTC (5:40 a.m. EDT).
Credit: NASA Goddard MODIS Rapid Response Team
NASA Sees Tropical Cyclone Anais Headed Near La Reunion Island

Tropical Cyclone Anais, the first tropical cyclone of the Southern Indian Ocean's tropical cyclone season, has strengthened over the weekend of Oct. 13 and 14 and by Oct. 15, the storm was packing sustained winds near 100 knots (115 mph/185 kph).

The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument aboard NASA's Aqua satellite captured a visible image of Tropical Cyclone Anais off Madagascar on Oct. 15 at 0940 UTC (5:40 a.m. EDT) and revealed an eye. Multi-spectral satellite imagery showed that convection has continued to decrease around Anais' ragged eye, indicating that the storm may be weakening.

On Oct. 15 at 1500 UTC (11 a.m. EDT) Anais was 650 nautical miles (748 miles/1,024 km) northeast of La Reunion, and has been moving to the southwest at 8 knots (9.2 mph/14.8 kph).

Over the next several days, Anais is forecast to move past La Reunion Island, while the center of the storm stays to the north and west of the island. As the storm moves further southward, it will move into waters below the 80 degree Fahrenheit (26.6 Celsius) threshold needed to maintain the system. In addition to the cooler waters wind shear is forecast to increase, so Anais is expected to weaken over the next several days.

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



Oct. 12, 2012

TRMM image of TS01S ›View larger image
When NASA's TRMM satellite passed over Tropical Cyclone 01S on Oct. 12 at 0741 UTC (3:41 a.m. EDT), light to moderate rainfall (blue and green) was occurring over most of the storm at a rate between .78 to 1.57 inches/20 to 40 mm per hour.
Credit: NASA/SSAI, Hal Pierce
NASA Spots First Tropical Cyclone of Southern Indian Ocean Season

The very first tropical cyclone of the Southern Indian Ocean season has been born, and NASA's TRMM satellite captured an image of its rainfall.

On Oct. 12 at 1500 UTC (11 a.m. EDT), Tropical Cyclone 01S (TC01S) was "born" about 90 nautical miles (103.6 miles/166.7 km) west-southwest of Diego Garcia, near 8.3 South latitude and 70.6 East longitude. Diego Garcia is a coral atoll located in the south central Indian Ocean and is part of the British Indian Ocean Territory. It is about 1,970 nautical miles (3,650 km) east of Tanzania, Africa.

TC01S had maximum sustained winds near 35 knots (40 mph/64.8 kph), so no sooner formed, than it became a tropical storm. TC01S was moving to the west-southwest at 6 knots (7 mph/11 kph).

When NASA's Tropical Rainfall Measuring Mission (TRMM) satellite passed over TC01S on Oct. 12 at 0741 UTC (3:41 a.m. EDT), the precipitation radar instrument detected light to moderate rainfall occurring over the center and in a band of thunderstorms wrapping into the center from the southwest. That rain was falling at a rate between .78 to 1.57 inches/20 to 40 mm per hour.

Microwave satellite imagery showed that the system is consolidating, and confirmed the band of thunderstorms wrapping into the center from the southern quadrant.

TC01S is in a good environment to continue strengthening. There is low wind shear and warm waters, two factors that allow a tropical cyclone to intensify.

In last year's season, the first tropical cyclone formed on Dec. 5, 2011, about 545 nautical miles west of the Cocos Islands. This year, we're off to an earlier start.

Forecasters at the Joint Typhoon Warning Center expect TC01S to continue intensifying over the next three days, Oct. 12, 13 and 14, before wind shear increases and sea surface temperatures decrease.

Text credit: Rob Gutro/Hal Pierce
NASA's Goddard Space Flight Center, Greenbelt, Md.