Hurricane Season 2010: Tropical Depression 14W (Northwest Pacific Ocean)

NASA Sees Tropical Depression 14W Fading From Facing Foes

Infrared satellite imagery from NASA's Atmospheric Infrared Sounder (AIRS) instrument provided forecasters with a look at the waning convection happening inside Tropical Depression 14W as it lingers and fizzles out near Hainan Island, China today. There are three environmental factors that are bringing an end to Tropical Depression 14W, two in the atmosphere, and one in the ocean.

Infrared satellite imagery on Oct. 5 and Oct. 6 showed a big decrease in Tropical Depression 14W's (TD14W) convection. That's significant, because convection is the rapidly rising air that forms the thunderstorms that power a tropical depression, tropical storm or hurricane. Without that power, the storm fizzles. That's what's happening to TD14W.

When NASA's Aqua satellite flew over the storm from space on October 5 at 18:17 UTC (2:17 p.m. EDT), the AIRS instrument aboard the spacecraft captured infrared imagery of its cloud-top temperatures. At that time, there was a small area of cloud tops that were as cold as or colder than -63F, but they've warmed since then and the strong convection is almost gone. Warming cloud tops indicate cloud tops are less high than they were before, and less uplift, or force in warm rising air to form thunderstorms. Satellite imagery has also shown that the low-level circulation center is poorly defined, and the storm was falling apart.

The three environmental factors that are working to dissipate whatever is left of TD14W today, Oct. 6, are increasing wind vertical shear, a layer of dry air blowing in on easterly winds from Hong Kong, and cooler sea surface temperatures. Those three factors are "enemies" to maintaining a tropical cyclone and TD14W is rapidly dissipating.

Text credit: Rob Gutro

NASA's Goddard Space Flight Center, Greenbelt, Md.