When Dr. Wells talks to Barry, they pass a broken cage with the name Grodd on it. Gorilla Grodd is one of the Flash's oldest foes.
When Barry's speed is being tested at the airfield testing facility, the logo on the sign is that of Ferris Air. Carol Ferris is the owner of the company and a love interest of Hal Jordan, a.k.a. Green Lantern.
The time of Barry Allen's coma is said to be nine months. This is almost the exact distance between Barry's appearance on Arrow (2012) in which he is struck by lightning (December 11, 2013) and when he wakes up in the show/the premiere of the show (October 9, 2014).
When Iris sees the footage of the "tornado" damage on the television at Jitters Java, it is seen on Channel 52. This is a nod to DC Comics' "The New 52," the 2011 relaunch of all of its comics' series following the conclusion of the "Flashpoint" crossover storyline.