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 . A disturbance to the southwest of Guam developed into Tropical Storm Roger on October 3 , and later on the same day the tropical disturbance which would later become Typhoon Tip developed to the south of Pohnpei .