 Early on 29 January, the BoM reported that a tropical low had developed within the monsoon trough about to the north of the Gove Peninsula in the Northern Territory.During that day the low rapidly developed further as it moved south-eastwards, before early on 29 January TCWC Brisbane reported that the low had developed into a category 1 tropical cyclone and named it Sadie as the system started to move southwards.Later that day the JTWC initiated advisories on Cyclone Sadie and designated it as Tropical Cyclone 14P, while the system started to move towards the east and was near its peak 1-minute maximum sustained windspeeds of 85 km/h (50 mph).