MANILA, May 10 (Reuters) - Thousands of passengers were stranded in seaports and some domestic flights were canceled as Typhoon Noul strengthened further before its expected landfall in the northeastern tip of the Philippines on Sunday. The typhoon was packing winds of up to 170 kph (105 mph), with gusts of up to 205 kph (125 mph), as it approached the rice-producing provinces of Isabela and Cagayan about 400 km (250 miles) north of the capital, Manila.