Tropical Storm Mindulle Forms Northwest of Guam

A smaller center of circulation consolidated within a much larger cyclonic gyre that extends from the Marianas north to Japan and west to China and the system has been designated Tropical Storm Mindulle.  At 11:00 a.m. EDT on Friday the center of Tropical Storm Mindulle was located at latitude 19.5°N and longitude 141.0°E which put it about 410 miles (655 km) south of Iwo To.  Mindule was moving toward the north-northwest at 11 m.p.h.  The maximum sustained wind speed was 50 m.p.h. (80 km/h) and there were wind gusts to 65 m.p.h. (105 km/h).  The minimum surface pressure was 992 mb.

The circulation around Tropical Storm Mindulle is still organizing.  A primary rainband is wrapping about three quarters of the way around the broad center of circulation.  There are few thunderstorms close to the core of tropical storm.  Scattered thunderstorms are forming in broken bands outside the primary rainband.  The thunderstorms in the primary rainband are generating some upper level divergence which is mainly pumping mass to the southwest of the center of circulation.

Tropical Storm Mindulle is in an environment that is favorable for slow intensification.  It is moving over water where the Sea Surface Temperature is near 31°C.  The upper level pattern near Mindulle is quite complex with a number of different features.  A narrow upper level ridge is just north of Mindulle and it is producing northeasterly winds that are blowing across the top of the tropical storm.  The northeasterly winds are contributing to the fact that most of the thunderstorms are west of the center of circulation and they are causing moderate vertical wind shear.  The vertical wind shear is inhibiting intensification.  Tropical Storm Mindulle is expected to extract enough energy from the ocean to intensify.  However, intensification will be slow while the core of the circulation organizes.

Tropical Storm Mindule is moving around the eastern portion of the large cyclonic gyre mentioned above.  That gyre is steering Mindulle toward the north-northwest and a general motion toward the north is expected to continue.  On its anticipated track Tropical Storm Mindulle could pass near Iwo To in about 24 hours.  Mindulle could be near Tokyo, Japan in about three days.