The structure of Tropical Cyclone Nathan improved on Sunday and it intensified slowly.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Nathan was located at latitude 13.9°N and longitude 149.8° which put it about 300 miles east-northeast of Cooktown, about 420 miles north-northeast of Townsville, Australia and about 250 miles north of Willis Island.  Nathan was moving toward the east-southeast at 3 m.p.h.  The maximum sustained wind speed was 65 m.p.h. and there were gusts to 80 m.p.h.  The minimum surface pressure was 984 mb.

Spiral bands of thunderstorms wrapped around the center of circulation and the structure of Nathan looks more well organized.  It is over warm Sea Surface Temperatures and the upper level winds are not too strong.  As a result, Nathan appears to be developing stronger upper level outflow.  The upper level outflow is pumping out mass, which is allowing the pressure to decrease and the wind speed to increase.  The environment around Nathan could support further intensification during the next 48 hours.

A ridge located northeast of Nathan is steering it slowly toward the south and that motion is likely to continue over the short term.  The winds steering the tropical cyclone could weaken in 24 to 48 hours, which could result in a period of little movement.  Later in the week a second ridge is expected to build northwest of Nathan and start to steer it westward which would move it closer to the east coast of Australia.   The projected track could bring Nathan very close to Willis Island in three or four days.