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Hurricane Season 2011: Tropical Cyclone 02S (Southern Indian Ocean)
12.08.11
 
This image from MODIS taken on Dec. 9 at 0931 UTC (4:31 a.m. EST) shows Tropical Storm 02S continuing to spin. › View larger image
In this image of the remnant low pressure area, formerly known as Tropical Storm 02S, the storm continues to show spin. The image is from the MODIS instrument on NASA's Aqua satellite and was taken on Dec. 9 at 0931 UTC (4:31 a.m. EST).
Credit: NASA/NRL
NASA Sees Tropical Cyclone 02S's Remnants Still Struggling

Early on Dec. 9, NASA's Aqua satellite passed over the remnant low pressure area of what was once Tropical Cyclone 02S in the Southern Indian Ocean. Satellite imagery showed that the system still had rotation but it was in no shape to make a comeback.

During the morning of Dec. 9, TC02S's remnants were centered about 580 nautical miles east-northeast of La Reunion Island near 16.6 South latitude and 64.5 East longitude. Minimum atmospheric pressure is near 1007 millibars, and maximum sustained winds are near 20 knots (23 mph/37 kmh).

The MODIS instrument on NASA's Aqua satellite captured an image of Tropical Cyclone 02S's (TC02S) remnants on Dec. 9 at 0931 UTC (4:31 a.m. EST). The satellite image showed thin bands of clouds circling a low level center, but that center was fully exposed to outside winds. The bulk of the low's clouds were about 100 nautical miles southeast of the center, an indication that the strongest wind shear was coming from the northwest. The low is currently encountering moderate wind shear, which is preventing it from getting reorganized and its moving to an area of stronger wind shear.

The Joint Typhoon Warning Center gives TC02S a low chance for redevelopment over the weekend as long as it keeps getting hammered by wind shear.

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



Dec. 8, 2011

MODIS captured a visible image of Tropical Cyclone 02S on Dec. 8 at 0845 UTC (3:45 a.m. EST). › View larger image
NASA's Aqua satellite flew over the remnants of Tropical Cyclone 02S on Dec. 8 at 0845 UTC (3:45 a.m. EST), and the MODIS instrument captured a visible image of the low pressure area. The remnants still appear rounded and have circulation, although the low-level center is exposed to outside winds.
Credit: NASA Goddard MODIS Rapid Response Team
NASA's Aqua Satellite Catches Tropical Cyclone 02S Struggling to Come Back

Tropical Cyclone 02S degenerated to remnant status early on Dec. 8 as NASA's Aqua satellite passed overhead and captured a visible image of the storm.

NASA's Aqua satellite flew over the remnants of Tropical Cyclone 02S on Dec. 8 at 0845 UTC (3:45 a.m. EST), and the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument captured a visible image of the low pressure area. The remnants still appear rounded and have circulation but the sustained winds have dropped below the threshold for tropical depression status. In addition, the storm's low-level center is currently exposed to outside winds, which could weaken the low pressure area.

The remnants of Tropical Cyclone 02S (TC02S) were located about 680 nautical miles east-northeast of La Reunion island in the Southern Indian Ocean, near 16.8 South latitude and 66.7 East longitude. Infrared imagery from the Atmospheric Infrared Sounder (AIRS) instrument onboard Aqua noticed deep convection redeveloped around the storm's center.

Maximum sustained surface winds within TC02S are estimated between 20 to 25 knots (23 to 29 mph/37 to 46 kmh) and minimum sea level pressure is estimated to be near 1004 millibars. Because the convection (rising air that forms thunderstorms that make up a tropical cyclone) is persistent, the Joint Typhoon Warning Center have given the low a medium chance and once again becoming a tropical depression.

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



Dec. 7, 2011

TRMM provided a › View larger image
TRMM provided a "top down" rainfall analysis of Tropical Storm 02S on Dec. 7 at 12:33 UTC (7:33 a.m. EST). Light to moderate rainfall (green and blue) was falling near to the east and south of the center at a rate between .78 to 1.57 inches/20 to 40 mm per hour). There were no areas of heavy (red) rainfall and there was no rainfall on the northwestern side of the storm.
Credit: NASA/SSAI, Hal Pierce
NASA's TRMM Satellite Sees Rainfall Fading in Dying Tropical Cyclone 02S

NASA's TRMM satellite passed over Tropical Storm 02S early today in the Southern Indian Ocean and noticed that rainfall was occurring mostly on one side of the storm.

The Tropical Rainfall Measuring Mission (TRMM) satellite provided a "top down" rainfall analysis of Tropical Storm 02S on Dec. 7 at 12:33 UTC (7:33 a.m. EST). TRMM saw light to moderate rainfall was falling east and south of the storm's center at a rate between .78 to 1.57 inches/20 to 40 mm per hour). There were no areas of heavy rainfall and there was no rainfall on the northwestern side of the storm.

At 0600 UTC (1 a.m. EST) on Wednesday, Dec. 7, 2011, Tropical Storm 02S had weakened to a tropical depression. Tropical Depression 02S (TD02S) had maximum sustained winds near 30 knots (35 mph/55 kmh). It was located about 605 nautical miles south-southwest of Diego Garcia, near 16.3 South and 67.3 East. TD02S was moving to the west at 5 knots (6 mph/9kmh).

TD02S's low-level center is now exposed fully to outside winds, which means that wind shear can have a strong weakening effect on the cyclone, although it is currently in an area of weak shear.

The Joint Typhoon Warning Center (JTWC) forecast calls for TD02S to move slowly westward and weaken as the wind shear increases. JTWC forecasters expect the tropical depression to weaken to a remnant low pressure area over the next couple of days, and issued their final warning on the storm.

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



Dec. 6, 2011

MODIS captured a visible image of Tropical Storm 02S on Dec. 6, 2011 at 4 a.m. EST. › View larger image
When NASA's Aqua satellite passed over Tropical Storm 02S on Dec. 6, 2011 at 4 a.m. EST it captured a visible image of the cyclone. The image showed a strong concentration of powerful thunderstorms around the center of circulation and bands of thunderstorms from the east and north feeding into the center.
Credit: NASA/NRL
NASA Satellite Sees Second Indian Ocean Tropical Storm Form Quickly After the First

The cyclone season in the southern hemisphere is off to a fast start as the second tropical cyclone formed in the Indian Ocean two days after the first one formed. NASA's Aqua satellite captured a great image of Tropical Storm 02S today.

Tropical Storm 02S (TS02S) formed on Dec. 6, 2011 at 0900 UTC (4 a.m. EST). It had maximum sustained winds of 35 knots (40 mph/65 kmh) and was moving to the southwest at 5 knots (6 mph/9 kmh). It was located about 685 miles east-northeast of Port Louis, Mauritius, near 17.2 South latitude and 69.1 East longitude.

When NASA's Aqua satellite passed over Tropical Storm 02S at 0900 UTC (4 a.m. EST) this morning, it captured a visible image of the cyclone. The image showed a strong concentration of powerful thunderstorms around the center of circulation and bands of thunderstorms from the east and north feeding into the center. Those bands of thunderstorms are indications of a strengthening storm.

The Joint Typhoon Warning Center, the organization responsible for forecasts of tropical cyclones in that region noted today that in addition to visible imagery, "multispectral satellite imagery depicts tightly-curved low-level banding wrapping into a well-defined low-level circulation center with limited deep convection over the eastern semi-circle."

TS02S is expected to intensify slightly before running into strong westerly wind shear that will weaken the cyclone as it moves west in the Southern Indian Ocean.

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