Three low pressure areas formed the monsoon trough that extended from the Philippines to the Marshall Islands. An area of disturbed weather to the southwest of Guam eventually strengthened into Tropical Storm Roger on October 3. Later on the same day, the tropical system which would later become Typhoon Tip formed to the south of Pohnpei. Because Roger was so close, the storm that would become Tip was not able to strengthen much. However, it gradually organized as it moved towards the west. The tropical disturbance moved slowly and and slowly made a loop to the southeast of Chuuk. A Reconnaissance Aircraft flight into the system late on October 4 confirmed the existence of a circulation center. A bit later, on October 5, the Joint Typhoon Warning Center (JTWC) called the system Tropical Depression Twenty-Three.