Koppu Makes Landfall South of Hong Kong, China

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