Prapiroon formed as a tropical depression over the western Pacific Ocean on October 7, 2012. It strengthened into a tropical storm the following day, and on October 9 became a typhoon, Unisys Weather reported. On October 11, the U.S. Navy’s Joint Typhoon Warning Center (JTWC) reported that Prapiroon had maximum sustained winds of 95 knots (175 kilometers per hour) and gusts up to 115 knots (215 kilometers per hour). The storm was located about 415 nautical miles (770 kilometers) south of Kadena Air Base, Okinawa, Japan.
The Moderate Resolution Imaging Spectroradiometer (MODIS) on NASA’s Terra satellite captured this natural-color image of Prapiroon on October 11. The storm had a distinct eye and spiral arms spanning hundreds of kilometers. Prapiroon’s clouds extended over the northern Philippines and skirted Taiwan.
The JTWC forecast that Prapiroon would strengthen somewhat over the next several hours, and maintain that strength through 48 hours. As of October 11, Prapiroon was moving toward the west-northwest, but the JTWC storm track showed the storm veering sharply toward the northeast around October 12.