Typhoon Rumbia had weakened to a tropical storm and moved over southern China when NASA's TRMM satellite flew above on July 2, 2013 at 0316 UTC and measured its rainfall rates.
An analysis of rainfall from TRMM Microwave Imager (TMI) and Precipitation (PR) data shows that Rumbia was dropping rain at a rate of over 92mm/hour (~3.6 inches) in areas of southern China near the Gulf of Tonkin. An intense but narrow feeder band near Hong Kong is shown streaming heavy rainfall into China from the South China Sea.
An image showing a 3-D slice through of tropical storm Rumbia was created at NASA's Goddard Space Flight Center in Greenbelt, Md. using TRMM Precipitation Radar data. Those data showed that the thunderstorms near Rumbia's center of circulation were then reaching heights mainly below 13 km (~8.1 miles). Some powerful thunderstorms in the feeder band near Hong Kong were found to reach to heights of 15 km (~9.3 miles).
Just before TRMM flew overhead, Tropical storm Rumba had made landfall over southeastern China on July 2, 2013 at 0300 UTC (July 1 at 11 p.m. EDT). The storm was 231 miles east of Hanoi, Vietnam near 21.4 north and 110.0 east. Rumbia's maximum sustained winds were near 50 knots (57 mph/92 kph) and dropping.
According to the Joint Typhoon Warning Center, radar imagery from Haikou, China at 0300 UTC (July 1 at 11 p.m. EDT), showed that the tightly-curved banding of thunderstorms became less organized, and had weakened.
On July 2, China's National Meteorological Centre (NMC) issued a blue category warning of typhoon at 6:00 p.m. (Beijing Time). The blue category warning means strong winds are expected along coastal Guangxi, and Beibu Gulf. Central and western Guangxi and southern Yunnan can expect heavy rainfall and gusty winds. In central Guangxi, there will be isolated areas of heavy rainfall as high as (100-120 mm/4.0 to 4.7 inches).
According to the NMC, "Severe tropical storm Rumbia has weakened into a tropical storm at 12:00 [p.m. local time] today. At 17:00 (5 p.m. local time), it was centered over Laibin city of Guangxi Zhuang Autonomous region (23.4°N, 109.0°E ) with maximum wind force up to scale 8 (18 meters/second) [64 kph/40 mph]."
Rumbia was moving to the northwest at 11 knots (12.6 mph/20 kph) and is expected to dissipate over China in the next day or two.
NASA's Goddard Space Flight Center