CECILY
1973-74 season · AU197374_05U
History
Severe Tropical Cyclone Cecily was an intense early-season system that formed and spent its entire life over open water during December 1973. It developed from a low embedded in an early monsoonal trough over the Timor Sea, north of the Kimberley, on 11 December. Drifting west-southwestward across unusually warm seas, the disturbance consolidated quickly, and the Tropical Cyclone Warning Centre in Perth named it Cecily on 12 December when it lay roughly 300 km north-northwest of Broome.
Steered by a strong mid-level ridge sitting over the Australian continent, Cecily took a south-southwestward to southwestward path that ran roughly parallel to the Kimberley and Pilbara coastlines, but always well offshore. Deepening accelerated on 14 December, when the system reached Category 3 severe tropical cyclone intensity on the Australian scale. At its peak, located well off the North West Cape, Cecily's central pressure fell to approximately 955 hPa, with maximum 10-minute sustained winds estimated near 140–150 km/h (75–80 knots) and gusts over the open ocean exceeding 195 km/h.
After peaking, Cecily continued west-southwestward away from the Australian coast and into the central Indian Ocean. There it encountered progressively cooler sea surface temperatures and strengthening vertical wind shear, which eroded the core. The system fell below tropical cyclone intensity on 18 December and was last identified on 19 December, having dissipated over open water without ever threatening a coastal crossing.
Because Cecily stayed several hundred kilometres offshore throughout its life, its destructive inner core never affected coastal settlements, and no land-based structural damage, injuries or deaths were attributed to the system. Its main operational consequence was at sea: gale and storm warnings were maintained for the North West Shelf shipping corridor, commercial vessels altered their routes to avoid the circulation, and offshore oil and gas exploration craft adopted standard heavy-weather procedures, afterwards reporting no damage. Cecily was one of the earliest of many systems in what proved to be an exceptionally active 1973–74 Australian region cyclone season.
Sources: Bureau of Meteorology report Wikipedia
View full track data (65 observations)
| Date/Time (UTC) | Category | Position | Pressure | Wind |
|---|---|---|---|---|
| 1973-12-11 00:01:00 | 1 | -9.9, 100.1 | 1005 hPa | 10 km/h |
| 1973-12-11 03:00:00 | 1 | -10.0, 100.0 | 1005 hPa | 10 km/h |
| 1973-12-11 06:00:00 | 1 | -10.1, 100.0 | 1003 hPa | 10 km/h |
| 1973-12-11 09:00:00 | 1 | -10.2, 99.9 | 1001 hPa | 13 km/h |
| 1973-12-11 12:00:00 | 1 | -10.3, 99.8 | 1002 hPa | 13 km/h |
| 1973-12-11 15:00:00 | 1 | -10.4, 99.7 | 1003 hPa | 13 km/h |
| 1973-12-11 18:00:00 | 1 | -10.5, 99.6 | 1004 hPa | 13 km/h |
| 1973-12-11 21:00:00 | 1 | -10.6, 99.5 | 1003 hPa | 13 km/h |
| 1973-12-12 00:01:00 | 1 | -10.6, 99.5 | 1003 hPa | 13 km/h |
| 1973-12-12 03:00:00 | 1 | -10.7, 99.4 | 1003 hPa | 13 km/h |
| 1973-12-12 06:00:00 | 1 | -10.9, 99.4 | 1002 hPa | 13 km/h |
| 1973-12-12 09:00:00 | 1 | -11.0, 99.5 | 1000 hPa | 13 km/h |
| 1973-12-12 12:00:00 | 1 | -11.2, 99.5 | 998 hPa | 13 km/h |
| 1973-12-12 15:00:00 | 1 | -11.3, 99.6 | 997 hPa | 15 km/h |
| 1973-12-12 18:00:00 | 1 | -11.4, 99.6 | 996 hPa | 15 km/h |
| 1973-12-12 21:00:00 | 1 | -11.5, 99.7 | 995 hPa | 15 km/h |
| 1973-12-13 00:01:00 | 1 | -11.6, 99.8 | 994 hPa | 18 km/h |
| 1973-12-13 03:00:00 | 1 | -11.7, 99.7 | 994 hPa | 18 km/h |
| 1973-12-13 06:00:00 | 1 | -11.9, 99.5 | 992 hPa | 21 km/h |
| 1973-12-13 09:00:00 | 1 | -12.2, 99.3 | 990 hPa | 23 km/h |
| 1973-12-13 12:00:00 | 1 | -12.5, 99.0 | 988 hPa | 23 km/h |
| 1973-12-13 15:00:00 | 1 | -12.9, 98.6 | 986 hPa | 26 km/h |
| 1973-12-13 18:00:00 | 1 | -13.4, 98.1 | 984 hPa | 26 km/h |
| 1973-12-13 21:00:00 | 1 | -14.0, 97.6 | 982 hPa | 28 km/h |
| 1973-12-14 00:01:00 | 1 | -14.6, 97.0 | 981 hPa | 28 km/h |
| 1973-12-14 03:00:00 | 1 | -15.0, 96.5 | 981 hPa | 28 km/h |
| 1973-12-14 06:00:00 | 1 | -15.3, 96.1 | 980 hPa | 28 km/h |
| 1973-12-14 09:00:00 | 1 | -15.7, 95.8 | 978 hPa | 31 km/h |
| 1973-12-14 12:00:00 | 1 | -16.1, 95.5 | 976 hPa | 31 km/h |
| 1973-12-14 15:00:00 | 1 | -16.5, 95.2 | 974 hPa | 33 km/h |
| 1973-12-14 18:00:00 | 1 | -16.9, 95.0 | 974 hPa | 33 km/h |
| 1973-12-14 21:00:00 | 1 | -17.3, 94.8 | 974 hPa | 36 km/h |
| 1973-12-15 00:01:00 | 1 | -17.7, 94.7 | 973 hPa | 36 km/h |
| 1973-12-15 03:00:00 | 1 | -18.0, 94.6 | 973 hPa | 36 km/h |
| 1973-12-15 06:00:00 | 1 | -18.4, 94.4 | 973 hPa | 36 km/h |
| 1973-12-15 09:00:00 | 1 | -18.7, 94.2 | 975 hPa | 36 km/h |
| 1973-12-15 12:00:00 | 1 | -19.1, 94.0 | 980 hPa | 33 km/h |
| 1973-12-15 15:00:00 | 1 | -19.5, 93.9 | 984 hPa | 31 km/h |
| 1973-12-15 18:00:00 | 1 | -19.9, 93.8 | 985 hPa | 28 km/h |
| 1973-12-15 21:00:00 | 1 | -20.3, 93.7 | 986 hPa | 28 km/h |
| 1973-12-16 00:01:00 | 1 | -20.8, 93.7 | 988 hPa | 26 km/h |
| 1973-12-16 03:00:00 | 1 | -21.2, 93.7 | 989 hPa | 26 km/h |
| 1973-12-16 06:00:00 | 1 | -21.7, 93.9 | 988 hPa | 26 km/h |
| 1973-12-16 09:00:00 | 1 | -22.1, 94.1 | 989 hPa | 26 km/h |
| 1973-12-16 12:00:00 | 1 | -22.6, 94.4 | 993 hPa | 26 km/h |
| 1973-12-16 15:00:00 | 1 | -23.0, 94.7 | 994 hPa | 23 km/h |
| 1973-12-16 18:00:00 | 1 | -23.5, 94.9 | 993 hPa | 21 km/h |
| 1973-12-16 21:00:00 | 1 | -23.9, 95.1 | 992 hPa | 21 km/h |
| 1973-12-17 00:01:00 | 1 | -24.4, 95.3 | 994 hPa | 21 km/h |
| 1973-12-17 03:00:00 | 1 | -24.8, 95.4 | 995 hPa | 21 km/h |
| 1973-12-17 06:00:00 | 1 | -25.1, 95.5 | 994 hPa | 21 km/h |
| 1973-12-17 09:00:00 | 1 | -25.3, 95.5 | 994 hPa | 21 km/h |
| 1973-12-17 12:00:00 | 1 | -25.5, 95.5 | 999 hPa | 21 km/h |
| 1973-12-17 15:00:00 | 1 | -25.7, 95.5 | 1003 hPa | 15 km/h |
| 1973-12-17 18:00:00 | 1 | -25.9, 95.5 | 1002 hPa | 13 km/h |
| 1973-12-17 21:00:00 | 1 | -26.1, 95.5 | 1002 hPa | 13 km/h |
| 1973-12-18 00:01:00 | 1 | -26.4, 95.5 | 1005 hPa | 13 km/h |
| 1973-12-18 03:00:00 | 1 | -26.8, 95.4 | 1005 hPa | 13 km/h |
| 1973-12-18 06:00:00 | 1 | -27.2, 95.2 | 1002 hPa | 13 km/h |
| 1973-12-18 09:00:00 | 1 | -27.6, 94.9 | 1003 hPa | 13 km/h |
| 1973-12-18 12:00:00 | 1 | -28.0, 94.6 | 1004 hPa | 13 km/h |
| 1973-12-18 15:00:00 | 1 | -28.3, 94.0 | 1005 hPa | 13 km/h |
| 1973-12-18 18:00:00 | 1 | -28.5, 93.2 | 1004 hPa | 13 km/h |
| 1973-12-18 21:00:00 | 1 | -28.7, 92.4 | 1004 hPa | 13 km/h |
| 1973-12-19 00:01:00 | 1 | -28.8, 91.5 | 1005 hPa | 13 km/h |