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Hurricane Season 2011: Tropical Storm 97W (Northwest Pacific)
04.07.11
 
AIRS data showed cloud top temperatures indicating strong convection (purple) within 97W. › View larger image
NASA's Aqua satellite captured an infrared image of the tropical low pressure area called "System 97W" on April 6 at 0611 UTC (2:11 a.m. EDT). The AIRS data showed cloud top temperatures as cold as or colder than -63 degrees Fahrenheit (-52 Celsius) indicating strong convection (purple)
Credit: NASA JPL, Ed Olsen
System 97W Socked By Shear

Wind shear quickly put an end to the development of the tropical low named "System 97W" in the South Pacific. The low was developing near Brunei yesterday and was even showing some signs of strong convection, but wind shear, the enemy to a developing tropical cyclone, increased broke down the structure of the low pressure area.

Wind shear is a difference in wind speed and direction over a relatively short distance in the atmosphere. Vertical wind shear attacked 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).

Increased wind shear today caused System 97W to fall apart and quickly dissipate, putting an end to its chances for growing into a tropical cyclone.

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



April 6, 2011

AIRS data showed cloud top temperatures indicating strong convection (purple) within 97W. › View larger image
NASA's Aqua satellite captured an infrared image of the tropical low pressure area called "System 97W" on April 6 at 0611 UTC (2:11 a.m. EDT). The AIRS data showed cloud top temperatures as cold as or colder than -63 degrees Fahrenheit (-52 Celsius) indicating strong convection (purple)
Credit: NASA JPL, Ed Olsen
Infrared NASA Data Shows a Developing Tropical Cyclone Near Brunei

Infrared data from NASA's Aqua satellite has seen potential in a developing tropical low pressure system near Brunei.

Brunei is located on the north coast of the island of Borneo, in Southeast Asia. Apart from its coastline with the South China Sea, it is completely surrounded by the state of Sarawak, Malaysia.

The Atmospheric Infrared Sounder (AIRS) instrument that flies aboard NASA's Aqua satellite captured an infrared image of the tropical low pressure area called "System 97W" on April 6 at 0611 UTC (2:11 a.m. EDT). Infrared data basically takes the temperature of atmospheric, land or oceanic objects. The infrared data revealed the coldest temperatures were in thunderstorm cloud tops around the center of System 97W's circulation. Those cloud tops were as cold as or colder than -63 degrees Fahrenheit (-52 Celsius) indicating strong convection (rapidly rising air that forms the thunderstorms that power a tropical cyclone). That's an indication that the storm is getting stronger. There is also a banding of thunderstorms around the low-level center of circulation.

AIRS data also showed that the sea surface temperatures were above 80F (26.7 C), which is the threshold for maintaining a tropical cyclone, so the water remains a power source for intensification.

At 0600 UTC on April 6, 2011, System 97W was about 170 miles west-northwest of Brunei near 6.2 North and 112.4 East. Maximum sustained surface winds are estimated at 15 to 20 knots (17-23 mph/28-37 kmh). Minimum sea level pressure is estimated to be near 1008 millibars.

The Joint Typhoon Warning Center currently gives System 97W a fair chance at becoming a tropical storm in the next 24 hours. NASA's Aqua satellite is watching and waiting.

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