Latimer snapped an Owen Pederson feed past Thunderbirds goaltender Thomas Milic from behind the net to make it 3-0 Ice.
Winnipeg scored all of their goals in the first two periods and hung on to get the win as Seattle made it interesting with a pair of third period tallies along with a late goal post.
Connor Mclennon, Evan Friesen and Carson Latimer scored for Winnipeg.
Owen Pederson had a pair of assists for the Ice.
Daniel Hauser made 27 saves for Winnipeg, who moved their playoff record to 13-2.
Reid Schaefer had the lone goal on the night for the Thunderbirds.
Thomas Milic turned aside 25 shots for Seattle, who dropped to 12-3 in the post-season.
Connnor Mclennon got the Ice on the board with a power play marker 9:13 into the first period when he took a feed from Ben Zloty before curling in toward the net and unleashing a high wrister, beating Milic glove side.
The goal was his 14th of the playoffs and extended his goal scoring streak to four games.
Mclennon nearly gave Winnipeg a two-goal cushion with 6:47 left in the first when Milic foiled him on a two-on-one.
Winnipeg got their two-goal lead at 15:22 when Zack Ostapchuk broke up a Seattle rush in the neutral zone before getting the puck to Owen Pederson who worked his way into the Thunderbird zone.
Pederson slipped Thunderbird defenceman Nolan Alan's check before getting a shot on goal that Milic stopped but the ensuing rebound landed right on Evan Friesen's stick which the Ice forward buried.
The goal was his 5th of the playoffs.
Carson Latimer made it 3-0 just over seven minutes into the second when he converted a Owen Pederson feed from behind the net, snapping a high wrister past Milic, beating him high blocker side.
The goal was his 2nd of the playoffs.
Reid Schaefer got Seattle on the board 28 seconds into the third when he deflected a Dylan Guenther shot past Hauser to make it 3-1.
The goal was his 7th of the playoffs.
Seattle pulled to within a goal at 18:18 of the third with an extra attacker as Kevin Korchinski converted Kyle Crnkovic's cross-crease feed after he moved in from the blue line.
SHOTS-SEATTLE 29 WINNIPEG 28
ATTENDANCE-5531
