Tropical storm Man-yi formed on September 12, 2013, in the northwestern Pacific Ocean as the sixteenth tropical depression and by September 13 it strengthened into a tropical storm.
When Terra satellite passed over newborn Man-yi it captured an image that clearly showed two vortices rotating around a large center of circulation. Forecasters at the Joint Typhoon Warning Center expect these two different vortices will combine with the larger, broad central circulation, allowing Man-yi to consolidate.
On September 13 at 09:00 UTC Tropical Storm Man-yi had maximum sustained winds near 35 knots/40.2 mph/64.8 km/h. It was moving to the west-northwest at 11 knots/12.6 mph/20.3 km/h. Man-yi was centered near 22.5 north and 141.0 east, just 157 nautical miles/180.7 miles/290.8 km south of the island of Iwo To, Japan.
Tropical Storm Man-yi forecast track. Forecast warning, credit: JTWC
Man-yi is expected to intensify to typhoon strength as it curves from northwest to northeast. On the forecast track issued by the Joint Typhoon Warning Center, Man-yi is expected to approach Tokyo on September 16 as a typhoon.
This MODIS image shows the bulk of clouds and showers on the northwestern and southeastern sides of the storm, but those were associated with the two different vortices or whirling masses of clouds and showers, that are rotating around the storm's actual center. Satellite data showed bands of strong thunderstorms around the southeastern vortex, which is the vortex with the strongest winds. Thunderstorms associated with the northwestern vortex are also strengthening as convection deepens. Image credit: NASA Goddard MODIS Rapid Response Team
Featured image: Two vortices circling a larger center of newborn Tropical Storm Man-yi on September 13 at 01:15 UTC.