A tropical low formed in the weak monsoon trough just north of Darwin on 2 April 1999. Middle level ridging pushed the low westward over the following days through the Timor Sea. Tropical cyclone Gwenda formed in the Indian Ocean to the southwest of Timor overnight on 4 April 1999. It was the only cyclone to form in Australian waters during the month of April. During its lifetime it was a very intense cyclone of average size. Gwenda intensified very rapidly late on 5 April. By the evening of 6 April the central pressure was estimated to be near 900 hPa (Category 5). It moved on a due southward course towards the Pilbara coast overnight on 6 April and then on the morning of 7 April the track changed towards the south-southeast towards the town of Port Hedland. During the evening as the cyclone approached to within 100 kilometres of Port Hedland, the cyclone experienced very strong wind shear and weakened rapidly. The cyclone crossed the coast 50 kilometres to the east of Port Hedland around midnight. At Port Hedland gale force winds were reported for a period of about 5 hours commencing at 2100 WST in the evening. Following landfall the cyclone weakened further and eventually merged into the heat trough.
For more details see the TC Gwenda Report (pdf)
Track and intensity
All times in WST - subtract 8 hours to convert to UTC.