Updated

Persistent rain forced NASCAR to cancel the first of a two-day Sprint Cup Series test session at Charlotte Motor Speedway on Thursday.

Thirty-three Sprint Cup teams are scheduled to participate in testing at this 1.5-mile racetrack, as they continue to familiarize themselves with the new sixth generation or "Gen 6" race car for the 2013 season. NASCAR is not extending the test to Saturday, but weather permitting, is giving teams an extra 90 minutes on Friday. There is no rain in the forecast for the Charlotte area tomorrow but temperatures are expected to be in the low 40s during the afternoon.

A two-day test session was held at Charlotte last month, but several teams did not participate in it. Teams did test the redesigned car this past week at Daytona International Speedway. The season-opening Daytona 500 is scheduled for Feb. 24.

Since there is a current short supply of parts and pieces for the new car, teams are behind in their preparations for the upcoming season.

"Obviously, this is the first new car we've had in quite a few years, so being behind is not a bad thing when you have new cars," said Brian Pattie, who is the crew chief for Clint Bowyer's No. 15 Toyota at Michael Waltrip Racing. "We're not where we were 12 months ago, as far as prepping for Daytona."

Each of the three auto manufacturers in NASCAR's top series -- Chevrolet, Ford and Toyota -- have designs on its new cars that are considerably different from the most recent ones used in the sport from 2007-12.