The TRMM-based, near-real time Multi-satellite Precipitation Analysis (MPA) at the NASA Goddard Space Flight Center monitors rainfall over the global tropics. The first image shows MPA rainfall totals for the period 16 November to 3 December 2004. Overlaid on the rainfall totals are the tracks associated with the passage of Typhoons Muifa and Nanmadol. Muifa moved northwest parallel to the Philippines before slowing and making a loop east of Luzon. The storm then moved west-southwest cutting across the north- central islands. Nanmadol started further east and moved steadily west- northwest before crossing the northern part of Luzon. The highest amounts recorded by the MPA are on the order of 50 inches (darkest red areas). These amounts are mainly offshore east of the northern island of Luzon and are due primarily to Muifa. However, just north of Dingalan Bay along the eastern side of Luzon, rainfall totals exceed 40 inches (smaller red area). Most of the this rainfall is a result of the unnamed storm, Winnie and Nanmadol. Similar amounts occur over parts of southeastern Luzon and the island of Catanduanes. In fact, nearly the entire island of Luzon received 15 inches of rain (green areas) or higher for the period. Torrential downpours over the eastern slopes of the mountainous and hilly terrain in northern Luzon led to massive mudslides and flash floods and accounted for the greatest loss of life. The towns of Infanta, Real and General Nakar in the Quezon region east of Manila bore the brunt.

The second image shows Typhoon Nanmadol after crossing the Philippines. The image was taken at 22:29 on the 2nd of December and shows the horizontal distribution of rain intensity as seen from above by the TRMM satellite. Rain rates in the center swath are from the TRMM Precipitation Radar (PR), the first precipitation radar in space, while rain rates in the outer swath are from the TRMM Microwave Imager (TMI). The rain rates are overlaid on infrared (IR) data from the TRMM Visible Infrared Scanner (VIRS). TRMM shows that Nanmadol has weakened significantly after crossing Luzon. Heavy convection is absent near the center, and a closed eyewall is not visible. At this time, Nanmadol was still classified as a strong Category 3 storm with winds estimated at 110 knots (127 mph) by the Joint Typhoon Warning Center but would continue to weaken. The storm made landfall as a more powerful Category 4 storm back on the 2nd with maximum sustained winds estimated at 120 knots (138 mph).