On the last leg of his journey Tuesday - less than 2 1/2 hours from his doorstep in Mayfair - Stellfox hit stormy weather on a stretch of the Pennsylvania Turnpike near Newville and lost control of his bike.
The motorcycle careened into a guardrail, throwing Stellfox from the seat, Cumberland County coroner Charley Hall said. He had been wearing a helmet, but died at the scene of his injuries.
"My biggest joy is that he was doing what he loved," his mother told the Daily News. "He texted about how beautiful the country was, and he was so happy that he got the opportunity to see it."
Stellfox is survived by his mother; his father, who served in the Marines and the Navy; his sister, Megan; a niece and three nephews. His older brother, Sean, died in 2010 at age 31.
One of Stellfox's final Instagram and Twitter posts is a haunting testament to the heavy rain that eventually played a role in his tragic death.
"Caught in the storm from hell. Think I'm an hour or two out of Pittsburgh," he wrote at 12:42 a.m. Tuesday, with a screen shot of GPS weather radar showing heavy rain over his location outside Cleveland. He added that he was also sick - but had a positive outlook anyway.
"[Supposed] to be bad [tomorrow] too, I think," he wrote. "Oh well, had a good run of weather throughout the country."
News of the officer's death rocked the Police Department.
"He had a nose just to do a good job and to get big arrests, and he was just a great cop," said 39th District Officer Matt Lally, who worked with Stellfox for 10 years. "It's a very trying job, and he made it a little easier. . . . This really crushed a lot of people."
Lt. David Bonk, who was Stellfox's sergeant in the 39th for eight years, echoed Lally.
"He never complained," Bonk said. "You could give him a police car with no air conditioning and windows that didn't roll down, and he'd go out and do police work."
Other colleagues are campaigning for a song to be dedicated in Stellfox's honor during Friday's Luke Bryan concert at Lincoln Financial Field. "A lot of Philly cops will be at the concert, and Luke Bryan's 'Drink a Beer' is one of the best memorial songs," said another officer, who asked not to be identified.
Jane Stellfox said she's been honored to see the outpouring of love for her son, an avid BMX biker when he wasn't patrolling the streets of Nicetown and Tioga.
Fellow officers remembered their fallen comrade as generous and intelligent, always quick with a joke or a helping hand.
"He's the type of guy that if he only had $20 to his name, he was gonna spend it on his friends," Lally said.
On Twitter: @morganzalot