The Japanese Geostationary Meteorological Satellite (GMS) imagery indicated extensive convection during most of the last week of December 1978 over northern tropical regions of Australia. Late on 28 December 1978 a weak low pressure system appeared in eastern Arnhem Land and during the following day drifted into the northwestern Gulf of Carpentaria. At 0000 UTC 29 December 1978 the cloud pattern was fairly well organised and by 2000 UTC that day the first gale was reported from an automatic weather station.
The cyclone moved steadily east-southeastwards and developed in intensity. Maximum development (a central pressure of 980 hPa, estimated by the analysis technique of Dvorak 1975) was attained about six hours before landfall near Edward River Mission at 1100 UTC 31 December 1978. The strongest reported uinds were 120 km/h at Edward River Mission during landfall and later at Fitzroy Island. No significant wind damage resulted.
Heavy to flood rains accompanied Peter . Mount Bellenden Ker (70 km south of Cairns) recorded 1140 mm in the 24 hours to 2300 UTC 5 January 1979, an Australian record (this rain gauge is located 1554.5 m above sea level). Other significant recordings were 402 mm at Cooktown in the 24 hours to 2300 GblT 31 December 1978 and 435 mm at Millaa Millaa in the 24 hours to 2300 UTC 2 January 1979.
Serious flooding occurred from Tully to Cooktown, especially around Cairns. Flood damage was estimated at $10 million and there were two deaths.