Tag Archives: SH26

Tropical Cyclone Ann Forms Over Coral Sea

Tropical Cyclone Ann formed over the Coral Sea on Saturday.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Ann was located at latitude 16.3°S and longitude 158.7°E which put it about 875 miles (1410 km) east of Cairns, Australia.  Ann was moving toward the west at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 40 m.p.h. (65 km/h) and there were wind gusts to 50 m.p.h. (80 km/h).  The minimum surface pressure was 999 mb.

A distinct low level center of circulation became more evident in satellite images of a low pressure system over the eastern Coral Sea on Saturday and the system was designated as Tropical Cyclone Ann.  A rainband wrapped around the southern and western sides of the center of circulation.  A microwave satellite image indicated that the band may have wrapped completely around the center in the middle levels of the circulation.  Storms near the center of circulation began to generate upper level divergence which was pumping mass away from the tropical cyclone.  The circulation around Tropical Cyclone Ann was relatively small.  Winds to tropical storm force extended out about 85 miles (135 km) from the center of circulation in the southern half of Ann.

Tropical Cyclone Ann will move through an environment somewhat favorable for intensification during the next day or two.  Ann will move over water where the Sea Surface Temperature is near 28.5°C.  It will move south of an upper level ridge.  The ridge will produce easterly winds which will cause some vertical wind shear.  The shear will inhibit intensification, but it is not likely to be strong enough to prevent intensification.  Tropical Cyclone Ann is likely to intensify during the next 24 hours.

The ridge will steer Tropical Cyclone Ann toward the west-northwest during the next two to three days.  On its anticipated track Tropical Cyclone Ann will approach the Cape York Peninsula in northern Queensland in about 72 hours.  Ann could bring gusty winds and locally heavy rain.

Elsewhere around the tropics in the southern hemisphere, Tropical Cyclone Lili was weakening near the coast of East Timor.  At 5:00 p.m. EDT on Saturday the center of Tropical Cyclone Lili was located at latitude 9.1°S and longitude 126.8°E which put it about 120 miles (195 km) east-northeast of Suai, East Timor.  Lili was moving toward the west at 4 m.p.h. (6 km/h).  The maximum sustained wind speed was 35 m.p.h. (55 km/h) and there were wind gusts to 45 m.p.h. (75 km/h).  The minimum surface pressure was 1000 mb.

Tropical Cyclone Lili Forms Over Timor Sea

Tropical Cyclone Lili formed over the Timor Sea on Thursday.  At 11:00 a.m. EDT on Thursday the center of Tropical Cyclone Lili was located at latitude 9.1°S and longitude 128.8°E which put it about 100 miles (160 km) southeast of Tutuala, East Timor.  Lili was moving toward the south-southwest at 5 m.p.h. (8 km/h).  The maximum sustained wind speed was 45 m.p.h. (75 km/h) and there were wind gusts to 60 m.p.h. (95 km/h).  The minimum surface pressure was 991 mb.

The circulation around a low pressure system over the Timor Sea exhibited more organization on Thursday and the system was designated as Tropical Cyclone Lili.  Several bands of showers and thunderstorms began to wrap around the low level center of circulation.  Additional bands of showers and thunderstorms began to develop around the periphery of the circulation.  Storms near the center of circulation were generating upper level divergence which was pumping mass away from the tropical cyclone.   The circulation around Tropical Cyclone Lili was relatively small.  Winds to tropical storm force only extended out about 60 miles (95 km) from the center of circulation.

Tropical Cyclone Lili will move through an environment favorable for intensification during the next 12 to 24 hours.  Lili will move over water where the Sea Surface Temperature is near 29°C.  It will move under the western portion of an upper level ridge.  Tropical Cyclone Lili will move through an area where the upper level winds are not too strong during the next 12 to 24 hours and there will not be a lot of vertical wind shear.  Lili could intensify during that period.  Tropical Cyclone Lili will move closer to the western end of the ridge in about 24 hours.  There are strong northerly winds blowing around the western end of the ridge and there will be more vertical wind shear.  If the shear increases, then the circulation around Lili is likely to weaken.

Tropical Cyclone Lili will move north of a subtropical ridge.  The ridge is likely to steer Lili more toward the west.  On its anticipated track Tropical Cyclone Lili could reach East Timor in about 36 hours.  Lili will bring gusty winds, but heavy rain and flooding are greater risks.  An alternative forecast scenario is possible.  If the vertical wind shear is not too strong and the vertical structure of Tropical Cyclone Lili remains intact, the upper level ridge could steer Lili more toward the south.  In that case Tropical Cyclone Lili could bring rain to Western Australia.