Rosie was a small cyclone that developed rapidly overnight from 21 to 22 April quickly reaching category 2 intensity before weakening as it passed near Christmas Island.
The most significant impact was the heavy swell at high tide at the port area of Christmas Island at about 0000 UTC on 22 April. The Harbour master reported waves of 5-7 m that damaged some facilities on the shore and tore a long-line mooring from its anchor.
This was the first tropical low monitored by the newly established Jakarta Tropical Cyclone Warning Centre (TCWC). While it was named by Perth TCWC once it moved south of 10°S, the reanalysis shows it reached cyclone intensity just north of 10°S in Jakarta TCWC's area of responsibility.
For more details see the TC Rosie Report (pdf)
Track and intensity
All times in WST - subtract 8 hours to convert to UTC.