NASA watches a slow-moving Tropical Depression Sonamu

When NASA's Aqua satellite passed over Tropical Depression Sonamu on Jan. 8 at 0641 UTC (1:41 a.m. EST/U.S.), the Atmospheric Infrared Sounder (AIRS) instrument aboard took an infrared look at the storm.

AIRS data showed that Sonamu still contained some very cold cloud top temperatures of -63F (-52C) indicating there was still some strong convection occurring near the center of circulation. The strongest storms were located southwest of the Mekong Delta at the time of the satellite image.

Multispectral satellite imagery showed that the low level circulation center was exposed to outside winds, and that the center was disorganized.

By 1500 UTC (10 a.m. EST/U.S.), Sonamu's maximum sustained winds were near 30 knots (34.5 mph/55.5 kph). Sonamu was centered near 5.3 north latitude and 109.3 east longitude, about 335 nautical miles (385.5 miles/620.4 km) west of Brunei. It was drifting to the southeast at 3 knots (3.4 mph/5.5 kph).

Sonamu is expected to continue its slow movement to the southeast and weaken further as wind shear increases. The Joint Typhoon Warning Center expects that Sonamu will make a landfall sometime on Jan. 10 in the Malaysian part of Borneo.