Tropical Depression 23W formed on Monday, Oct. 9 and by Tuesday, Oct. 10 it made landfall in northern Vietnam. NASA's Aqua satellite analyzed the depression in infrared light and determined the strongest storms were located in two countries.
Infrared light provides valuable temperature data to forecasters and cloud top temperatures give clues about highest, coldest, strongest storms within a hurricane.
On Oct. 10 at 2:00 a.m. EDT (0600 UTC) the Moderate Resolution Imaging Spectroradiometer or MODIS instrument aboard NASA's Aqua satellite analyzed Tropical Depression 23W's cloud top temperatures in infrared light. MODIS found cloud top temperatures of strongest thunderstorms over northwestern Vietnam and northeastern Laos. Temperatures in some of those storms were as cold as or colder than minus 80 degrees Fahrenheit (minus 62.2 Celsius). Cloud top temperatures that cold indicate strong storms that have the capability to create heavy rain.
On Oct. 10 at 0300 UTC (Oct. 9 at 11 p.m. EDT) the center of Tropical Depression 23W (23W) was located over northern Vietnam. It was near 18.4 degrees north latitude and 105.8 degrees east longitude, about 156 nautical miles south of Hanoi, Vietnam. 23W had maximum sustained winds near 30 knots (34.5 mph/55.5 kph) and was moving to the west-northwest at 13 knots (15 mph/24 kph).
The Joint Typhoon Warning Center expects that 23W will weaken to a remnant low pressure area and continue moving northwest through northern Laos and into Burma (Myanmar).