NASA eyes Typhoon Prapiroon's U-turn

Typhoon Prapiroon is making a U-turn in the Philippine Sea, changing direction from northwest to northeast. NASA's Aqua satellite captured an image of the typhoon as it began turning. Visible satellite imagery revealed its most powerful thunderstorms south and east of the center.

NASA's Aqua satellite passed over Typhoon Prapiroon on Oct. 10 at 0435 UTC (12:35 a.m. EDT) and captured a visible image of the storm. The Moderate Resolution Imaging Spectroradiometer (MODIS) instrument was able to get a visible image of the typhoon, because it was 1:35 p.m. local Asia/Tokyo time (and night time on the U.S. East coast at 12:35 a.m. EDT). The MODIS imagery revealed a well-defined center with tightly curved bands of thunderstorms wrapping into the low-level center of the storm. That's the mark of a strong storm. Although Prapiroon's eye was not apparent in the visible MODIS image, it was in microwave imagery from another satellite instrument.

Typhoon Prapiroon's maximum sustained winds were near 90 knots (103.6 mph/166.7 kph) on Wed. Oct. 10 at 1500 UTC (11 a.m. EDT or 12 a.m. on Thurs. Oct. 11 Asia/Tokyo Time). Prapiroon's center was located about 470 nautical miles (541 miles/870.4 km) south-southeast of Kadena Air Base, Okinawa, Japan, near 19.0 North and 129.6 East. The typhoon had already turned and was moving to the west-northwest at 7 knots (8 mph/12.9 kph).

Prapiroon made the U-turn because of a strong area of elongated high pressure called a ridge that is located south of Japan. The storm is moving around the southwestern edge of the high pressure area. Over the next several days, the storm is expected to intensify because it's in an area of low wind shear and warm waters.