BALTIMORE — The National Weather Service issued a tornado warning for the Baltimore area Friday. The twister never materialized, nor did a North Carolina comeback — until Sam Geiersbach touched down in the fourth quarter.

A graduate transfer from Richmond, Geiersbach scored five goals in the final six minutes and the top-seeded Tar Heels rallied from an eight-goal deficit to stun fourth-seeded Northwestern 15-14 in the NCAA Division I women’s lacrosse semifinals at Homewood Field. It was the biggest comeback at a final four since Virginia scored 10 straight to beat Duke by one in the 2007 semifinals.

North Carolina (21-0) kept its undefeated season alive and will meet either Boston College or Maryland in the championship game Sunday (12 p.m. ET, ESPN), its first appearance in the final since capturing its second NCAA title in 2016.

“As time was dwindling down, we just realized that this might be our last go at it,” Geiersbach said.  “In the back of my head, I was thinking about all the stories I had heard from these guys about them not making it to the national championship. For me, it was just putting it all in there for them, putting it on the line and getting us out of that rut.”

Nothing went right for the Tar Heels for the first three quarters. Northwestern stormed to a 6-0 lead, weathered a 96-minute delay and led 13-5 after Jill Girardi scored from deep on a low bouncer with 32 seconds remaining in the third quarter.

At that point, North Carolina had shot just 5-for-24, hitting five pipes while Wildcats goalie Madison Doucette did her best Rachel Hall impression denying the Tar Heels at every turn.

Geiersbach provided an omen of things to come, however, when she threaded a backdoor feed to Caitlyn Wurzburger for a quick stick on the doorstep with six seconds left.

Still, the Wildcats appeared to go comfortably ahead when Dylan Amonte scored to make it 14-7 with 10:15 remaining in the fourth quarter. Maybe they were too comfortable.

A minute later, Wurzburger dodged hard from behind the goal and scored on a diving shot in front of the crease to start the Tar Heels comeback. An Ortega goal made it 14-9.

It unraveled from there for Northwestern, which looked fatigued and overmatched. North Carolina sent double-teams flying all over the field, forcing the Wildcats into turnovers on seven of their last eight possessions.

“We started becoming a little too timid,” midfielder Jill Girardi said. “We have the philosophy of just going balls to the wall. That’s what we were for the first 45 minutes. We just kind of lost it. We went to their game plan. We didn’t play ours. That just kind of depleted us.”

Tar Heels midfielders Elizabeth Hillman and Ally Mastroianni combined to cause seven turnovers, while Wurzburger executed a pivotal trail check on Girardi while riding past the midfield with four minutes left.

“The thing that makes our team so resilient is our ability to trust and believe in one another,” Mastroianni said. “[Coach] Jenny [Levy] always says, ‘Refuse to go away.’”

Northwestern’s zone defense, so effective for most of the game, came unglued. Bolstered also by the move to another graduate transfer, Andie Aldave (Notre Dame), in the draw circle, the Tar Heels scored six goals in a matter of 4 minutes, 21 seconds. It happened that fast.

“We only had one timeout left. We tried to save it, then we called it. It was just too little too late,” Wildcats coach Kelly Amonte Hiller said. “We just couldn’t reclaim our composure. That hurt us.”

Geiersbach scored on a double rollback to tie it at 14 with 2:25 remaining, then she beat Girardi over the top and deposited the game-winning goal with a lefty laser with 1:06 left.

All five of Geiersbach’s goals came in the final 5:27; all five unassisted. Even UNC’s bench was in a state of disbelief, several reserves in practice apparel looking at each other with what-just-happened eyes as the Tar Heels celebrated on the field.

Northwestern had a chance to tie it when Lauren Gilbert picked off a clearing pass by embattled North Carolina goalie Taylor Moreno. But Moreno, who was briefly removed from the game midway through the third quarter, made a split save going to the ground on Gilbert with 28 seconds left as the Tar Heels held on.

“It was not my day, and that’s completely OK,” Moreno said, crediting freshman Alecia Nicholas for helping the defense reset during an eight-minute stretch. “They really locked in.”

“Sometimes that’s all you need,” Levy said. “One good save at the last moment.”

Few envisioned the Wildcats making it this far when they fell to Maryland in their regular season finale and then Rutgers in the Big Ten tournament — or going further back, when Tewaaraton Award finalist Izzy Scane tore her ACL in the fall.

But Gilbert and Girardi, both graduate students, have taken their star turns in 2022. Both were phenomenal Friday. North Carolina had no answer for Gilbert’s speed at the outset. The graduate student from Oregon scored five goals — all unassisted. Girardi added three goals and six draw controls.

“They’ve reestablished our dominance in the lacrosse community,” Amonte Hiller said of her fifth-year players.

Northwestern scored on six of its first eight possessions and had North Carolina on its heels before a weather delay sent both teams to the locker room with the Wildcats leading 6-0. They retreated at 12:56 p.m. and reemerged at 2:16 p.m.

North Carolina players stretched and danced to Lupe Fiasco’s “The Show Goes On” while Northwestern players jogged the perimeter on their side. Play resumed at 2:32 p.m.

Ortega said the delay represented an energy shift. “Everyone felt that,” said Ortega, who had three goals and three assists despite seeing occasional face guards by Wildcats defenders.

North Carolina had no answer for Gilbert at the outset, but Northwestern had no answer for Geiersbach in the end.

After remarking that the Wildcats advanced to the final four without the help of any transfers, Amonte Hiller acknowledged the irony of it.

“But ultimately the transfer beat us,” she said.