Trailing 6-4 with two outs in the fifth inning of game two, Coopman and Harmon each took starting pitcher Maddison Woodruff over the left field fence for the Storm (20-12, 6-4 Iowa Conference).
But the Kohawks (27-5, 9-1) responded in the bottom half when Brandi Haight capped off her seven-RBI day with a grand slam, putting Coe ahead for good.
Bryn Johnson took the loss in relief of Allison Barloon, who pitched 2/3 of an inning. Johnson (3-3) kept the Kohawk offense in check until Haight's long ball. She finished the game allowing seven runs - three earned - off nine hits, striking out two.
Ashley Simon (19-1) got the win in relief, pitching the final 2 1/3 innings after no-hitting Simpson in game one.
Simpson couldn't figure out Simon in game one, gaining only two baserunners thanks to walks in the first and fifth innings.
Shannon Aguero hit a grand slam for Coe in the first inning, finishing 2-for-2 with four RBIs.
Kacee Arey (10-5) took the loss, giving up seven runs off eight hits in four innings.
Simpson returns to action Tuesday, April 19 when it travels to Storm Lake for a doubleheader against Buena Vista. First pitch is set for 3 p.m.