The first Tropical Depression of 2013 formed the western North Pacific Ocean today, and NASA's Terra satellite captured an infrared image of the "birth."
Tropical Depression Sonamu, otherwise known as Tropical Depression 01W developed near 8.6 north latitude and 118.6 east longitude, about 185 nautical miles (213 miles/342.6 km) northwest of Zamboanga, Philippines. Sonamu's center is located in the Sulu Sea and is expected to cross the southern end of Palawan before moving into the open waters of the South China Sea.
Sonamu developed from low pressure System 92W. At 1500 UTC (10 a.m. EST/U.S.), Sonamu had maximum sustained winds near 25 knots (28.7 mph/46.3 kph) and is expected to struggle to intensify as moderate to strong vertical wind shear continues to impact the storm. Sonamu is moving to the west at 17 knots (19.5 mph/31.8 kph) and is expected to continue in that general direction for the next couple of days.
When NASA's Terra satellite passed over Sonamu on Jan. 3 at 1413 UTC (9:13 a.m. EST/U.S.) the center was approaching southern Palawan. The Moderate Resolution Imaging Spectroradiometer or MODIS instrument captured an infrared image of Sonamu that showed its clouds had overspread southern Palawan.
Forecasters at the Joint Typhoon Warning Center, who forecast tropical cyclones in that area of the world, noted that infrared imagery showed that the low-level center is consolidating, and there is strong convection (rapidly rising air that condenses and forms the thunderstorms that make up a tropical cyclone) around the center. Satellite data also shows some banding of thunderstorms wrapping around the center.
By 0000 UTC on Jan. 4 (Jan. 3 at 7 p.m. EST/U.S.) Sonamu will have crossed Palawan and entered the South China Sea, where it is expected to track for the next several days.