NASA's Terra satellite recently analyzed the remnant low pressure area previously known as Tropical Depression 01W in infrared light as it showed a spark of new activity.
Four days ago, on January 9, Tropical Depression 01W was moving over the southern and central Philippines and weakened to a remnant low pressure area. Today, January 13, that low pressure area has worked its way across the South China Sea to the coast of Vietnam and is showing some signs of regeneration.
At 10:15 a.m. EST (1515 UTC) on Jan. 13 infrared data from the Moderate Resolution Imaging Spectroradiometer aboard NASA's Terra satellite showed cloud tops west and north of the center of the low were as cold as minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius). Cold cloud tops indicate the area of strongest storms that stretch highest into the troposphere. The higher they are, the colder the air temperature. The bands of thunderstorms with the coldest cloud tops were pushed north and west of center from southeasterly vertical wind shear. Infrared data also showed that the low-level center of circulation appears to be consolidating.
The Joint Typhoon Warning Center (JTWC) noted that multiple surface observations near the low-level center showed 15 to 20 knot (~17 to 23 mph/ ~27 to 37 kph) winds and sea level pressure near 1005 millibars.
JTWC noted that an analysis of upper-level winds shows that the remnant low pressure area is in a "marginally favorable environment" for further development. The remnant low is expected to slowly drift west toward the coast of Vietnam.
The potential for the development of a significant tropical cyclone within the next 24 hours is upgraded to medium.