 Through 15 March satellite imagery indicated increasing convection and organisation of the system, as well as decreasing wind sheer aloft, adding to the favourable conditions for strengthening.On 16 March, the system was designated Tropical Cyclone 18S by the Joint Typhoon Warning Center, with winds of .The system then crossed Melville and Bathurst Islands and moved into the Timor Sea, where it intensified, and was given the name Fay by the Australian Bureau of Meteorology.