Hours before they were killed in a fiery crash on the Merritt Parkway in Fairfield early Saturday, Tiffany and Chantel Osorio were in New York City, having a blast celebrating Chantel's 24th birthday.

The sisters, both Stratford residents and graduates of Notre Dame High School in Fairfield, tweeted Friday night about the celebratory day, and headed back to Connecticut early Saturday.

They were found dead

inside a Chevy Cobalt at about 6:30 a.m. Saturday near the Fairfield-Westport border after a fiery crash between the parkway's northbound Exits 42 and 44.

State Police said that Chantel was driving the car owned by Tiffany when it veered left over a soft grass median, then swerved right across both travel lanes of the highway. The car went off the right side of the road, striking a tree. The vehicle then spun around, striking a second tree and burst into flames.

The crash was initially reported as a brush fire, and firefighters from Fairfield and Westport were dispatched to the scene.

The flames engulfed the entire vehicle, and both women were pronounced dead at the scene, according to the accident report.

The bodies were taken to the Office of the Chief State Medical Examiner in Farmington. Officials said a positive identification will be made using dental records; the sisters were burned beyond recognition.

Earlier Friday, an account registered to Chantel Osorio tweeted: "My week was rough but my birthday has been goin great. Thank you all that have wished me happy birthday so far !!!"

Before leaving for New York City, Chantel tweeted she was "city-bound," and before the pair headed back to Connecticut, Tiffany Osorio tweeted "Omw (on may way) back to CT now."

The sisters were remembered Monday as outgoing and fun-loving.

"There was that one or two seconds of shock," said the Rev. Peter Cipriani, the school chaplain at Notre Dame High School. "And then immediately I felt the tears well into my eyes."

Cipriani taught Tiffany when she was a student at Notre Dame.

"Someone like that -- it makes you excited to get out of bed each day and come to a place like this, and that's why it's just devastating the world has lost someone like that," Cipriani said.

"The first word that comes to mind in describing Tiffany is `sass,' " he said. "I don't think I've known a more sassier girl, and yet I mean that as the biggest compliment. Wherever you happened to be in the school, you knew that Tiffany was close by -- you just had to listen -- but at the same time, very fun. That's what she was able to use her sass for -- more than anything, was for fun, get a few chuckles out of people."

Cipriani didn't know Chantel as well, but when he looked Monday at her yearbook photo, he was taken aback by the quote she chose to go with her photo:

"Life is short and so am I, so I'm going to do the best with them both before I die."

Chantel Osorio, who graduated from Southern Connecticut State University in 2009, held a state license as a pharmacy technician, according to an online database.

A poster memorializing the sisters is circulating on Facebook, and people who knew the sisters are taking to Twitter to leave their condolences.

Mike Millea tweeted that he had homeroom with Chantel all four years at Notre Dame.

"I cannot believe that she's gone," he wrote.

Dawud Peterson wrote on Facebook that his children were friends with the Osorio sisters.

"When my family heard the news, we were devastated," he wrote.

Shereffia Francis uploaded the poster on her Facebook page.

"You were both so young, the good die young and my prayer go out to your family, your parents especially," she wrote. "You ladies will be missed and never forgotten ... watch over us thru tough times."

The account @SportsFairfield, which covers sports throughout the county, tweeted, "Our thoughts are with the #NDFairfield community and the Osorio family as they mourn the loss of alumni Tiffany and Chantel."