Tropical Cyclone Dianne neared the coast of Western Australia on Friday morning. At 5:00 a.m. EDT on Friday the center of Tropical Cyclone Dianne was located at latitude 15.3°S and longitude 123.6°E which put the center about 140 miles (225 km) north of the Derby, Australia. Dianne was moving toward the south-southeast at 10 m.p.h. (16 km/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 991 mb.
A Warning is in effect for the area between Kuri Bay and Derby.
A Tropical Low strengthened to Tropical Cyclone Dianne near the coast of Western Australia during Thursday night. More thunderstorms formed near the center of Tropical Cyclone Dianne. More thunderstorms also formed in bands revolving around the center of Dianne’s circulation. Storms near the center of Dianne generated more upper level divergence that pumped mass away from the tropical cyclone. The removal of more mass caused the surface pressure to decrease.
The circulation around Tropical Cyclone Dianne was small. Winds to tropical storm force extended out 90 miles (145 km) from the center of Dianne’s circulation.
Tropical Cyclone Dianne will move through an environment somewhat favorable for intensification during the next few hours. Dianne will move over water where where the Sea Surface Temperatures are near 29°C. It will move under the northern part of an upper level ridge that extends from over Australia to the South Indian Ocean. The upper level ridge will produce easterly winds that will blow toward the top of the Tropical Low. Those winds will cause some vertical wind shear. The vertical wind shear will inhibit intensification, but the wind shear may not be enough to prevent intensification. Dianne could intensify during the next few hours.
Tropical Cyclone Dianne will move around the western end of a high pressure system over northern Australia. The high pressure system will steer Dianne toward the southeast during the next 24 hours. On its anticipated track, Tropical Cyclone Dianne will make landfall on the coast of Western Australia northeast of Derby in a few hours.
Tropical Cyclone Dianne will bring strong winds and locally heavy rain to parts of Western Australia. Heavy rain could cause flash floods in some locations.
Flood Watches are in effect for the Tanami Desert, the Western Desert and the Sandy Desert.
Elsewhere over the South Indian Ocean, Tropical Cyclone Courtney passed south of the Cocos Islands. At 5:00 a.m. EDT on Friday the center of Tropical Cyclone Courtney was located at latitude 16.9°S and longitude 94.9°E which put the center about 330 miles (530 km) south-southwest of the Cocos Islands. Courtney was moving toward the west at 18 m.p.h. (30 km/h). The maximum sustained wind speed was 90 m.p.h. (145 km/h) and there were wind gusts to 115 m.p.h. (185 km/h). The minimum surface pressure was 972 mb.