Cappie Pondexter scored 20 points, and Charles added 18 points and 14 rebounds to help New York (10-13) win its third straight game. The Liberty, fighting for a playoff spot, have won six of their last eight after a 4-11 start.
After Charles gave New York the lead, Pondexter added a basket just before the buzzer after Seattle missed two shots in the final 13 seconds.
Camille Little scored 22 points, and Crystal Langhorne added 17 for Seattle (9-17). They Storm have lost four in a row and five of their last six.
Seattle guard Temeka Johnson had a triple-double with 13 points, 11 assists and a career-high 10 rebounds. She started in place of Sue Bird, sidelined by a strained neck.