Doris began as a tropical depression in the Arafura Sea north of Melville Island on 12 March 1980. The low drifted slowly east with little development for about three days then becanie better organised on 15 March 1980. By 1200 UTC 15 March the central pressure had fallen to 999 hPa, winds near the centre reached gale force, and the depression was named tropical cyclone Doris .
The cyclone moved slowly south during 16 March 1980 while continuing to intensify. By 1800 UTC16 March 1980 the central pressure had fallen to 989 hPa but then strengthening upper easterlies both turned the cyclone to the west and disturbed its symmetry. The central pressure rose slowly to about 993 hPa by 0800 UTC 17 March 1980 when tropical cyclone Doris made landfall on the Arnhem Land coast between Nhulunbuy and Groote Eylandt.
Although the intense low-level structure of Doris was destroyed on landfall its well developed upper circulation retained its identity as the system moved west across the Top End of Northern Territory during 18 and 19 March 1980. After reaching the Joseph Bonaparte Gulf the depression moved quite rapidly west-southwest, later to become tropical cyclone Gloria in the lndian Ocean.
Tropical cyclone Doris produced heavy rain over Arnhem Land, without significant flooding. Extensive but minor damage occurred on Groote Eylandt and the Gove Peninsula although no lives were lost. The mining companies of Nabalco and Gemco incurred direct cost damages of about $150 000 while total community damage has been estimated at $500 000.
The westward moving tropical depression started to intensify as it moved across the Joseph Bonaparte Gulf early on 20 March 1980. The rate of development increased markedly as the depression moved from land to the lndian Ocean. Gloria reached tropical cyclone intensity by about 1400 UTC 21 March 1980 as estimated using GMS (Geostationary Meteorological Satellite) enhanced infrared imagery (i.e. about 24 hours after it moved from land to ocean). The cyclone accelerated westward and continued to strengthen, attaining peak intensity about 0900 UTC 25 March 1980 when the central pressure was estimated to be near 955 hPa. This intensity was maintained for about 30 hours during which the cyclone came under the influence of a strong northerly flow ahead of a middle-level trough. It commenced weakening late on 26 March 1980 as it accelerated to the south-southeast. Gloria became extratropical on 28 March 1980 and was captured by a cold front on 29 March 1980.
The track of Gloria is fairly typical of March tropical cyclones in the Western Region; an initial move westward and then recurvature in a south-easterly direction at about latitude 20°S. At 1200 UTC on 23 March 1980 a ship about 100 km from the storm centre reported a pressure of 997 hPa and a mean wind speed of 80 km/h. At that time the maximum mean wind speed near the centre was estimated to be approximately 100 km/h. No reports of damage were received.