When severe weather brought their Top of the Park opening night set to an abrupt halt Friday night, members My Dear Disco refused to let the rain and lightning stop the music. They just moved the show inside.

As the storm — with forecast winds as high as 70 miles per hour — hit, around 150 people took shelter in the lobby of Rackham Auditorium, including all five members of the Ann Arbor "dancethink" band. Although the lights flickered a few times, the power didn’t go out, so the group’s members set their equipment back up and started playing indoors, much to the delight of those assembled, who immediately began to cheer and dance.

The band played for about 20 minutes before University of Michigan officials called a halt to the impromptu set. By then, the weather had settled down to just a steady rain.

“The storm has passed. I think we have a little responsibility for that,” My Dear Disco guitarist Robert Lester told the crowd.

Around 3,000 people attended Top of the Park Friday night, estimated Ann Arbor Summer Festival executive director Robb Woulfe. As the inclement weather moved in from the west, the music was stopped at about 9 p.m., with an announcer urging people to take shelter in Rackham and in the Modern Languages Building, both adjacent to Ingalls Mall.

“This is not a test. Get inside,” he said. The rain hit at 9:20 p.m.

This is not the first time Top of the Park has tangled with Mother Nature on opening night. In 2008, an opening night show featuring My Dear Disco and theMacpodz was also cut short due to weather.

“It always rains on Top of the Park’s opening night,” observed local music promoter Matthew Altruda.

“These past couple of years — what’s up,” wondered Wolfe, joking “I’ve got to get out of show business.”

Prior to the bad weather, food vendors were doing a brisk business, volunteers were circulating in the crowd collecting donations to help keep the event free, and folks were spread out on blankets, parked in lawn chairs or just walking around Ingalls Mall people-watching. Many could be seen consulting weather radar on their smart phones and casting worried looks toward the darkening western horizon.

Ann Arborites Ann Agler, Margaret Flannery and Sharon St. Mary had their canvas chairs set up early, with a good view of the stage and the people passing by.

“This is a tradition,” Agler said. “Everybody loves Top of the Park.”

Lynne Friman of Saline said she enjoys running into friends at the event. “I know there’s always something interesting,” she observed. “And could there be a better name for an act than Tokyo Sexwhale?” she wondered, referring to the band that, along with Mucca Pazza, played prior to My Dear Disco’s abbreviated set.

Kelly Wegers of Ypsilanti was taking advantage of Top of the Park’s festive atmosphere to celebrate her birthday.

“This is the epitome of summer,” she said. Her partner, Bethany Shultz, agreed, adding, “I think it’s amazing and I love that it’s free, especially in this economy.”

For those who missed out on opening night, Top of the Park starts up at 5 p.m. Saturday with the Grassrootz Stage featuring Community High jazz combos. The music continues at the Rackham Stage with Saoco at 6:30, Orquesta Sensacional at 8:30 and a set in The Grove from DJ Nick Ayers at 10:30 p.m.

The annual outdoor component to the Ann Arbor Summer Festival continues though July 11 with a program of live bands and movies at dusk complementing ticketed mainstage events at nearby Power Center.

Roger LeLievre is a free-lance writer who covers music for AnnArbor.com.