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Hurricane Season 2009: Tropical Storm Koppu (Western Pacific)
09.15.09
 
September 15, 2009

The AIRS instrument infrared data indicated high, frigid thunderstorm cloud top temperatures before Koppu made landfall. > View larger image
The Aqua satellite also flew over Tropical Storm Koppu, September 14 at 2:35 p.m. EDT and the AIRS instrument infrared data indicated high, frigid thunderstorm cloud top temperatures before it made landfall south of Hong Kong.
Credit: NASA/JPL, Ed Olsen
Koppu Makes Landfall South of Hong Kong, China

Koppu briefly reached typhoon status before it made landfall just south of Hong Kong. Koppu's eye made landfall around 7 a.m. local time (Hong Kong) today, September 15 (11 p.m. EDT, September 14) and brought winds gusting to near 78 mph (Category one typhoon strength) to the southern Guangdong Province.

NASA's Aqua satellite captured an image of Koppu about 8 hours before its center made landfall, and revealed strong thunderstorms with very cold cloud tops as cold as -63F. Cloud top temperatures are important because they tell forecasters how high thunderstorms are, and the higher the thunderstorm, the more powerful. Those thunderstorms brought heavy downpours which led to minor flooding.

Prior to the Aqua's flight over Koppu at 8 p.m. EDT (4 a.m. local time, Hong Kong), Koppu had maximum sustained winds near 69 mph (60 knots), tropical storm strength. It was 75 miles southwest of Hong Kong, China and moving west-northwest near 14 mph. The Hong Kong Observatory had issued a "No. 8 Southeast Gale or Storm Signal, meaning that winds with mean speeds of 63 kilometres per hour (39 mph) or more are expected from the southeast quarter (of Hong Kong)."

At 2:45 a.m. local time (Hong Kong), the Hong Kong Observatory noted "the maximum sustained winds recorded at Cheung Chau, Chek Lap Kok and Kai Tak were 110, 75 and 71 kilometres per hour (68, 46 and 44 mph) with maximum gusts 131, 108 and 115 kilometres (81, 67, and 71 mph) per hour respectively."

Koppu is expected to weaken quickly to a tropical depression while continuing to move inland in a northwesterly direction.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center



September 14, 2009

The MODIS instrument revealed Koppu as a well-organized tropical storm near the southeastern China coast. > View larger image
NASA's Terra satellite captured Tropical Storm Koppu on September 13 using infrared imagery from the Moderate Imaging Spectroradiometer (MODIS) instrument and it revealed a well-organized tropical storm near the southeastern China coast.
Credit: NASA/MODIS Rapid Response
AIRS captured an infrared image of Tropical Storm Koppu's cold, high thunderstorm cloud tops on September 13. > View larger image
AIRS captured an infrared image of Tropical Storm Koppu's cold, high thunderstorm cloud tops on September 13, measuring temperatures as cold as -63 Fahrenheit.
Credit: NASA/JPL, Ed Olsen
Tropical Storm Koppu Poised for China Landfall

The latest tropical storm in the western Pacific formed on Sunday, and is poised to make landfall in mainland China on Tuesday, near typhoon strength (74 mph).

Tropical Storm Koppu, the sixteenth tropical cyclone in the western Pacific Ocean, also deemed "16W," had sustained winds near 69 mph (60 knots) today, September 14. Koppu is expected to strengthen just a little more before it makes landfall in China. It was centered near 20.6 north and 114.6 east, about 130 nautical miles south-southeast of Hong Kong, China. Koppu is forecast to move west-northwest near 10 mph and will make landfall on September 15. It is expected to dissipate within one or two days after landfall.

NASA's Terra satellite flew over Tropical Storm Koppu late last night at 03:20 UTC (11:20 p.m. EDT), and using infrared imagery from the Moderate Imaging Spectroradiometer (MODIS) instrument, captured a well organized tropical storm of the southeastern China coast. Landfall will bring heavy rains, heavy surf conditions along the coast and gusty winds.

Earlier, NASA's Aqua satellite flew over Koppu and used the Atmospheric Infrared Sounder (AIRS) instrument to read the temperatures of the storm's clouds at 1:41 a.m. EDT. AIRS showed very cold, high thunderstorm clouds, as cold or colder than -63 Fahrenheit.

Koppu will continue to track generally west-northwestward under the influence of the subtropical ridge until it makes landfall northwest of the Leizhou Peninsula during the day tomorrow.

Text credit: Rob Gutro, NASA/Goddard Space Flight Center