JACOB
1984-85 season · AU198485_09U
History
Severe Tropical Cyclone Jacob developed from a tropical low within the monsoon trough on 15 February 1985, approximately 450 kilometres west-northwest of the Cocos Islands in the South-East Indian Ocean. Its formation occurred during an exceptionally busy period in the basin, with Cyclones Hubert and Isobel active simultaneously in the same region during the highly active 1984–85 Australian cyclone season.
Steered by a strong mid-level ridge, Jacob tracked steadily west-southwestward into open ocean waters throughout its lifetime. It intensified rapidly over warm seas, reaching Category 4 status on the Australian scale by 20 February 1985, with a minimum central pressure of 950 hPa and peak 10-minute sustained winds of 165 km/h. The system maintained severe intensity for several days while remaining entirely over open water.
On 22 February, Jacob crossed the 80°E meridian, moving out of the Australian Bureau of Meteorology's area of responsibility and into the Southwest Indian Ocean basin, where it was subsequently monitored by forecasters based at La Réunion. It weakened progressively over cooler waters before fully dissipating. Jacob made no landfall at any point during its existence, posed no threat to the Australian coastline or nearby islands, and caused no recorded casualties, structural damage, or maritime incidents, though shipping advisories were issued for vessels operating in the affected waters.
Sources: Bureau of Meteorology report Wikipedia
View full track data (53 observations)
| Date/Time (UTC) | Category | Position | Pressure | Wind |
|---|---|---|---|---|
| 1985-02-15 00:00:00 | 1 | -9.0, 127.6 | 1003 hPa | 13 km/h |
| 1985-02-15 06:00:00 | 1 | -10.1, 127.3 | 1001 hPa | 13 km/h |
| 1985-02-15 12:00:00 | 1 | -11.0, 127.1 | 1000 hPa | 13 km/h |
| 1985-02-15 18:00:00 | 1 | -11.7, 126.7 | 1000 hPa | 13 km/h |
| 1985-02-16 00:00:00 | 1 | -12.1, 126.1 | 999 hPa | 13 km/h |
| 1985-02-16 06:00:00 | 1 | -12.3, 125.3 | 998 hPa | 13 km/h |
| 1985-02-16 12:00:00 | 1 | -12.5, 124.4 | 997 hPa | 15 km/h |
| 1985-02-16 18:00:00 | 1 | -12.6, 123.3 | 995 hPa | 15 km/h |
| 1985-02-17 00:00:00 | 1 | -12.7, 122.1 | 994 hPa | 18 km/h |
| 1985-02-17 06:00:00 | 1 | -13.1, 121.2 | 992 hPa | 21 km/h |
| 1985-02-17 12:00:00 | 1 | -13.4, 120.4 | 990 hPa | 21 km/h |
| 1985-02-17 18:00:00 | 1 | -13.8, 119.7 | 988 hPa | 21 km/h |
| 1985-02-18 00:00:00 | 1 | -14.1, 118.9 | 984 hPa | 23 km/h |
| 1985-02-18 06:00:00 | 1 | -14.4, 118.1 | 980 hPa | 23 km/h |
| 1985-02-18 12:00:00 | 1 | -14.7, 117.4 | 976 hPa | 26 km/h |
| 1985-02-18 18:00:00 | 1 | -14.8, 116.7 | 966 hPa | 28 km/h |
| 1985-02-19 00:00:00 | 1 | -15.0, 116.1 | 963 hPa | 28 km/h |
| 1985-02-19 06:00:00 | 1 | -15.1, 115.1 | 957 hPa | 31 km/h |
| 1985-02-19 12:00:00 | 1 | -15.2, 114.7 | 953 hPa | 33 km/h |
| 1985-02-19 18:00:00 | 1 | -15.4, 113.9 | 952 hPa | 36 km/h |
| 1985-02-20 00:00:00 | 1 | -15.5, 113.0 | 952 hPa | 39 km/h |
| 1985-02-20 06:00:00 | 1 | -15.7, 112.2 | 950 hPa | 39 km/h |
| 1985-02-20 12:00:00 | 1 | -15.7, 111.5 | 951 hPa | 36 km/h |
| 1985-02-20 18:00:00 | 1 | -15.8, 110.9 | 952 hPa | 36 km/h |
| 1985-02-21 00:00:00 | 1 | -15.9, 110.1 | 952 hPa | 36 km/h |
| 1985-02-21 06:00:00 | 1 | -15.9, 109.1 | 952 hPa | 36 km/h |
| 1985-02-21 12:00:00 | 1 | -16.1, 107.9 | 953 hPa | 36 km/h |
| 1985-02-21 18:00:00 | 1 | -16.3, 106.5 | 953 hPa | 36 km/h |
| 1985-02-22 00:00:00 | 1 | -16.9, 105.3 | 954 hPa | 36 km/h |
| 1985-02-22 06:00:00 | 1 | -17.5, 104.3 | 954 hPa | 36 km/h |
| 1985-02-22 12:00:00 | 1 | -18.0, 103.4 | 955 hPa | 36 km/h |
| 1985-02-22 18:00:00 | 1 | -18.3, 102.8 | 955 hPa | 33 km/h |
| 1985-02-23 00:00:00 | 1 | -18.7, 102.2 | 956 hPa | 28 km/h |
| 1985-02-23 06:00:00 | 1 | -19.3, 101.5 | 957 hPa | 26 km/h |
| 1985-02-23 12:00:00 | 1 | -20.1, 100.4 | 958 hPa | 26 km/h |
| 1985-02-23 18:00:00 | 1 | -20.8, 99.4 | 959 hPa | 26 km/h |
| 1985-02-24 00:00:00 | 1 | -21.8, 98.7 | 960 hPa | 26 km/h |
| 1985-02-24 06:00:00 | 1 | -22.7, 97.5 | 963 hPa | 26 km/h |
| 1985-02-24 12:00:00 | 1 | -23.7, 96.7 | 966 hPa | 23 km/h |
| 1985-02-24 18:00:00 | 1 | -24.9, 96.1 | 970 hPa | 23 km/h |
| 1985-02-25 00:00:00 | 1 | -26.1, 95.8 | 976 hPa | 23 km/h |
| 1985-02-25 06:00:00 | 1 | -27.5, 95.5 | 979 hPa | 23 km/h |
| 1985-02-25 12:00:00 | 1 | -29.0, 95.4 | 982 hPa | 23 km/h |
| 1985-02-25 18:00:00 | 1 | -30.7, 95.6 | 985 hPa | 21 km/h |
| 1985-02-26 00:00:00 | 1 | -32.5, 96.1 | 988 hPa | 21 km/h |
| 1985-02-26 06:00:00 | 1 | -34.4, 97.4 | 992 hPa | 21 km/h |
| 1985-02-26 12:00:00 | 1 | -35.5, 98.8 | 994 hPa | 21 km/h |
| 1985-02-26 18:00:00 | 1 | -36.6, 100.2 | 995 hPa | 21 km/h |
| 1985-02-27 00:00:00 | 1 | -37.4, 101.7 | 996 hPa | 18 km/h |
| 1985-02-27 06:00:00 | 1 | -38.2, 103.2 | 997 hPa | 15 km/h |
| 1985-02-27 12:00:00 | 1 | -38.8, 105.6 | 998 hPa | 15 km/h |
| 1985-02-27 18:00:00 | 1 | -39.2, 108.5 | 999 hPa | 13 km/h |
| 1985-02-28 00:00:00 | 1 | -39.2, 111.4 | 1002 hPa | 13 km/h |