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Hurricane Season 2011: Tropical Storm 02W (Northwest Pacific)
04.06.11
 
AIRS showed cold, high, strong thunderstorms around the center of circulation in TS02W with heavy rainfall. › View larger image
NASA's AIRS instrument captured this infrared image of Tropical Depression 2W on April 5 at 0353 UTC. It showed cold, high, strong thunderstorms around the center of circulation (purple) with heavy rainfall.
Credit: NASA/JPL, Ed Olsen
Second NW Pacific Depression Dissipating Quickly From Strong Wind Shear

After moving through the Northern Marianas, the second tropical depression of the Pacific Northwestern hurricane is dissipating as quickly as the first depression did earlier this week. Both didn't last more than a couple of days.

At 0300 UTC on April 6, Tropical Depression 02W (TD02W) was about 185 nautical miles north-northeast of Saipan, near 17.9 North and 147.7 East. It was moving east-northeast near 18 knots and is in a region of strong vertical wind shear greater than 25 knots (29 mph/46 kmh). Wind shear tears storm structure apart.

Wind shear is a difference in wind speed and direction over a relatively short distance in the atmosphere. Vertical wind shear attacks or batters the heat engine of a tropical cyclone, making it break down. With strong wind shear, tropical cyclones weaken as the upper circulation of the storm is blown away from the low level center. When the upper and lower levels become separated, or pushed in different directions like a spring standing up, the storm, like a spring, loses its ability to stand straight and can't function (a spring would fall over).

The Joint Typhoon Warning Center issued its final warning today on Tropical Depression 02W.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD


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April 5, 2011

AIRS showed cold, high, strong thunderstorms around the center of circulation in TS02W with heavy rainfall. › View larger image
NASA's AIRS instrument captured this infrared image of Tropical Depression 2W on April 5 at 0353 UTC. It showed cold, high, strong thunderstorms around the center of circulation (purple) with heavy rainfall.
Credit: NASA/JPL, Ed Olsen
NASA Sees Second NW Pacific Tropical Depression Form, Threatens Northern Marianas

The second tropical depression of the Northwestern Pacific Ocean season has formed, just as the first depression has dissipated. NASA's Aqua satellite captured an infrared image of the depression and observed some strong thunderstorms within, and the storm has already caused warnings to be posted.

On April 5, 2011, Tropical Depression 2W formed about 270 miles (434 km) NW of Anderson Air Force Base, Guam, near 16.1 South and 141.1 East. It was moving east-northeast near 19 knots (22 mph/35 kmh) and had maximum sustained winds near 30 knots (34 mph/55 kmh). The Northern Marianas are expected to feel the effects of the depression as it continues to move in that direction. A tropical storm warning is in force for Agriahan, Pagan and Alamagan Islands in the Northern Mariana Islands.

The Atmospheric Infrared Sounder (AIRS) instrument on NASA's Aqua satellite captured an infrared image of Tropical Depression 2W on April 5 at 0353 UTC. It showed cold, high, strong thunderstorms around the center of circulation with heavy rainfall west of the Northern Marianas islands.

The Joint Typhoon Warning Center forecast that the system will strengthen as it undergoes extra-tropical transitioning over the next day.

Text Credit: Rob Gutro, NASA's Goddard Space Flight Center, Greenbelt, MD