Tropical Cyclone Marcus moved back over the South Indian Ocean on Sunday and it strengthened rapidly north of Australia.  At 11:00 p.m. EDT on Sunday the center of Tropical Cyclone Marcus was located at latitude 15.0°S and longitude 122.8°E which put it about 215 miles (345 km) north-northeast of Broome, Australia.  Marcus was moving toward the west at 11 m.p.h. (17 km/h).  The maximum sustained wind speed was 75 m.p.h. (120 km/h) and there were wind gusts to 90 m.p.h. (145 km/h).  The minimum surface pressure was 987 mb.

Tropical Cyclone Marcus weakened when it moved over the northernmost part of Western Australia, but it began to strengthen quickly after the core moved back over water.  An eye rapidly reformed at the center of circulation.  A ring of strong thunderstorms redeveloped around the eye and the strongest winds were occurring in that ring of storms.  Bands of showers and thunderstorms were revolving around the core of the circulation.  Storms around the core were generating upper level divergence which was pumping mass away from the tropical cyclone.  The circulation of Tropical Cyclone Marcus was relatively compact.  Winds to tropical storm force extended out about 80 miles (130 km) from the center of circulation.

Tropical Cyclone Marcus will be moving through an environment very favorable for intensification during the next two days.  Marcus will move over water where the Sea Surface Temperature is near 30°C.  It will move through an area where the upper level winds are weak and there will be little vertical wind shear.  Tropical Cyclone Marcus is likely to continue to intensify rapidly and it could become the equivalent of a major hurricane in 24 to 36 hours.

Tropical Cyclone Marcus is moving around the northern side of a subtropical ridge over Australia, which is steering Marcus toward the west.  A general motion toward the west is forecast to continue for several more days.  Tropical Cyclone Marcus will reach the western end of the ridge in two or three days.  Marcus will turn toward the south at that time.  On its anticipated track Tropical Cyclone Marcus will move farther away from the coast of Western Australia during the next two days.