DENISE

History

Tropical Cyclone Denise was a notably late-season system that developed over the tropical eastern Indian Ocean in the second half of May 1975. It began as a tropical low embedded in an active equatorial trough on 19 May, near 10°S and 105°E, well off the northwestern Australian coast. Warm sea surface temperatures allowed the disturbance to organise quickly as it drifted southeast, and it reached tropical cyclone strength on 20 May, when the Bureau of Meteorology's Perth warning centre assigned the name Denise.

Steered southeastward between a ridge of high pressure to its south and an approaching mid-latitude trough, Denise continued to strengthen over open water. On 22 May it reached severe tropical cyclone status, Category 3 on the Australian scale, with a minimum central pressure of about 965 hPa and maximum sustained winds in the order of 130–140 km/h, with gusts over the ocean exceeding 180 km/h. Peak intensity occurred while the system was positioned well to the northwest of North West Cape.

As the cyclone tracked into higher latitudes, increasing vertical wind shear ahead of the upper trough and cooler waters quickly eroded its central convection. Denise recurved eastward, fell below cyclone intensity on 24 May and dissipated the following day without ever reaching the Western Australian coastline.

Because the system remained several hundred kilometres offshore throughout its life, no gales or significant rainfall affected Pilbara or Kimberley communities, and there were no casualties or structural damage. Gale and storm warnings were issued for North West Shelf shipping lanes, and offshore oil and gas facilities adopted heavy-weather precautions, but no damage resulted. Denise effectively closed out the destructive 1974–75 season.

Sources: Bureau of Meteorology report Wikipedia