Ann reached peak intensity on 12 May as a Category 2 tropical cyclone on the Australian scale, with 10-minute sustained winds of 100 km/h (65 mph) and a central barometric pressure of 990 hPa (29.23 inHg).

[18] Aided by warm sea surface temperatures and the favourable outflow provided by an anticyclone in the upper troposphere, deep convection continued to grow over the consolidating low-level circulation centre on 11 May.

[19] The storm was upgraded to a Category 1 tropical cyclone on the Australian scale by the BOM at 18:00 UTC on 11 May, while located approximately 1,420 km (880 mi) east of Cairns.

Analysis of satellite imagery indicated that easterly vertical wind shear had begun to increase near the system, and that drier air had started to become entrained into the circulation from the southwest.

[25][26] The BOM downgraded the cyclone to Category 1 at 06:00 UTC on 13 May as the central dense overcast shrunk to less than 20 nautical miles (37 km; 23 mi) in diameter.

[29] The system's decay was evident on satellite imagery, which displayed the effects of dry air, marginal ocean heat content, and increasing wind shear from the previously favourable upper-level anticyclone, now located well to the east.

[30][31] Gale-force winds soon became confined to the southwestern quadrant as the storm became devoid of central deep convection, leaving the low-level circulation centre exposed.

[4][32][33] Located 375 km (233 mi) northeast of Cairns, Ex-Tropical Cyclone Ann continued quickly west-northwestwards towards the coast of Far North Queensland.

[34] The tropical low made landfall near the town of Lockhart River on the east coast of Cape York Peninsula about 24 hours later, at 2:30 p.m. local time (04:30 UTC) on 15 May.

[20][35][36] Continuing on the same west-northwestwards track that it had maintained for the previous five days, the tropical low passed the northeastern coast of the Top End on 16 May while moving into the Arafura Sea.

After persisting for several days as a remnant tropical low, Ex-Tropical Cyclone Ann eventually dissipated by 06:30 UTC on 18 May in the Banda Sea, while located near East Timor and Indonesia's southern Maluku Islands.

[37][38][39] In preparation for the possibility of Ann making landfall on the Queensland coast at tropical cyclone intensity, the BOM issued a number of official warnings to the public in advance of the system's arrival.

Upon weakening to Category 1 strength at 18:00 UTC on 12 May, a tropical cyclone watch was issued for coastal and inland areas between Cape York and Port Douglas.

Willis Island, located approximately 450 km (280 mi) east of Cairns, experienced intermittent gale-force winds as Ann passed to the north, peaking at 72 km/h (45 mph) at 19:30 UTC on 13 May.