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Hurricane Season 2011: Tropical Depression 13W (Western North Pacific Ocean)
08.12.11
 
TRMM image of Tropical Depression 13W on August 11, 2011 at 1354 UTC (9:54 a.m. EDT). › View larger image
The TRMM satellite passed over the remnants of Tropical Depression 13W (TD13W) on August 11, 2011 at 1354 UTC (9:54 a.m. EDT). A TRMM rainfall analysis showed TD13W only had light rainfall (blue) and was dissipating south of Japan.
Credit: NASA/SSAI, Hal Pierce
NASA's TRMM Satellite Sees Tropical Depression 13W Dissipating

Tropical Depression 13W is dissipating south of Japan, and NASA's Tropical Rainfall Measuring Mission satellite noticed only light rainfall remaining in the system.

The TRMM satellite passed over the remnants of Tropical Depression 13W (TD13W) on August 11, 2011 at 1354 UTC (9:54 a.m. EDT). A TRMM rainfall analysis showed TD13W only had light rainfall and was dissipating south of Japan.

The last warning from the Joint Typhoon Warning Center issued its final warning on August 12 at 0300 UTC (August 11 at 11 p.m. EDT), when TD13W was located about 390 nautical miles south of Yokosuka, Japan near 28.8 North and 139.1 East. It had maximum sustained winds near 25 knots (29 mph/46 kmh) and was moving to the east near 9 knots (10 mph/16 kmh) as it continued to dissipate.

Text Credit: Rob Gutro, NASA Goddard Space Flight Center, Greenbelt, Md.



August 11, 2011

Cold cloud tops of the thunderstorms in Tropical Depression 13W in the open waters of the western North Pacific Ocean. › View larger image
The AIRS instrument on NASA's Aqua satellite saw the cold cloud tops of the thunderstorms in Tropical Depression 13W in the open waters of the western North Pacific Ocean on August 11, 2011 at 0353 UTC (Aug. 10 at 11:53 p.m. EDT). The most concentrated area of thunderstorms (purple) were northwest of the center of circulation. Japan lies to the north of the depression.
Credit: NASA/JPL, Ed Olsen
NASA Sees Strongest T-storms in Tropical Depression 13W Dislocated

The strongest thunderstorms in Tropical Depression 13W appear on NASA infrared imagery as being northwest of the storm's center.

When NASA's Aqua satellite flew over Tropical Depression 13W (TD13W) on August 11, the coldest thunderstorm cloud tops were northwest of the center of circulation. That means that the depression is battling wind shear, and that winds are pushing the strongest convection (rapidly rising air that forms thunderstorms that make up the tropical cyclone) to the northwest. The winds would be coming from the southeast. The convection also appears to be weakening during the morning hours.

Infrared imagery basically takes temperatures and the colder the cloud top, the higher it is, and that typically means the stronger the thunderstorm. Cloud top temperatures around TD13W's center were as cold as -62 Fahrenheit, the baseline for high cloud tops and strong thunderstorms. The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite took TD13W's cloud temperatures on August 11, 2011 at 0353 UTC (Aug. 10 at 11:53 p.m. EDT).

AIRS data also showed that the low-level circulation of the storm is fully exposed to the influence of winds. In addition, dry air is also wrapping around the storm and dry air saps the warm, humid air that helps form thunderstorms.

On August 10 at 1500 UTC (11 a.m. EDT), TD13W's maximum sustained winds were near 30 knots (34 mph). It was near 28.0 North and 137.9 East, about 470 nautical miles south of Tokyo, Japan.

TD13W is moving to the northeast at 9 knots (10 mph) and is expected to continue moving in that general direction over the next several days. On that track, TD13W will track parallel to the eastern Japan coastline, but remain far enough at sea, so that the coast will likely only experience some rough surf on eastern-facing shorelines. Currently, however, TD13W is generating 8-foot high seas.

Forecasters at the Joint Typhoon Warning Center expect that winds will become hostile in the next couple of days and continue to weaken it. Forecasters noted that it could even dissipate at sea in the next couple of days.

Text Credit: Rob Gutro, NASA Goddard Space Flight Center, Greenbelt, Md.



August 10, 2011

Image of Tropical Depression 13W on August 10 at 1239 UTC (8:39 a.m. EDT). › View larger image
NASA's Terra satellite captured an image of Tropical Depression 13W on August 10 at 1239 UTC (8:39 a.m. EDT). The depression appears as a rounded area of clouds. The strongest convection is limited to the northwestern sector of the depression.
Credit: NASA/NRL
NASA's Terra Satellite Sees Birth of Tropical Depression 13W

The thirteenth tropical depression of the western North Pacific hurricane season was born in open waters today and away from land.

Tropical Depression 13W has maximum sustained winds near 30 knots (34 mph) and is in open waters of the western North Pacific Ocean. On August 10, 2011 at 1500 UTC (11 a.m. EDT) it was located near 25.7N 136.1E, about 625 nautical miles south-southwest of Yokosuka, Japan. Tropical Depression 13W has moved north-northwestward at 10 knots (12 mph)and is expected to start turning to the northeast in the next day.

NASA's Terra satellite captured an image of Tropical Depression 13W on August 10 at 1239 UTC (8:39 a.m. EDT). The depression appears as a rounded area of clouds. The strongest convection is limited to the northwestern sector of the depression.

The depression appears to be in an environment that is conducive to further development.

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