NASA watches as Tropical Storm Bolaven develops

NASA's Aqua satellite has been monitoring the birth and progress of Tropical Storm Bolaven in the western North Pacific from Aug 19-20, 2012. The Atmospheric Infrared Sounder (AIRS) instrument has provided infrared satellite imagery that shows the development of colder thunderstorm cloud-top temperatures, that were indicative of strengthening storms. Tropical Storm Bolaven also took more of a rounded shape on August 20 as it continued to organize and intensify.

On August 19 at 03:11 UTC (Aug. 18 at 11:11 p.m. EDT) the AIRS image of Bolaven appeared loosely organized. At that time, the strongest thunderstorms appeared to be east of the center of circulation.

On August 20 at 3:53 UTC (Aug. 19 11:53 p.m. EDT), NASA's AIRS instrument on the Aqua satellite captured another infrared image of Bolaven. The infrared AIRS image showed the storm had a much tighter circulation and Bolaven's strongest thunderstorms were south of the center of circulation, where cloud top temperatures were colder than -63 Fahrenheit (-52 Celsius). Hours later, Bolaven was located about 400 nautical miles (460 miles/741 km) south of Iwo To, Japan, near 18.2 North latitude and 141.2 West longitude. It was moving to the north-northwest at 5 knots (5.7 mph/9.2 kmh) and had maximum sustained winds near 35 knots (40 mph/65 kmh).

Bolaven will continue strengthening as it moves to the west-northwest over the next couple of days in open waters of the western North Pacific Ocean. By August 24 forecasters at the Joint Typhoon Warning Center expect Bolaven to reach typhoon status.