Florida Gov. Charlie Crist (R) announced Thursday morning that he had raised more than $2.4 million during the third quarter for his Senate campaign, a total that more than doubles the nearly $1 million fundraising total of his top Republican competitor, former Florida Speaker Marco Rubio.Combined with his $4.3 million in fundraising during the second quarter, Crist’s campaign said in a release this morning that the governor had more than $6.2 million in cash on hand as of Sept. 30.Crist’s impressive haul from July through September reinforces his status as frontrunner in the race. But after raising just $350,000 in May and June, Rubio’s second-quarter total will continue to be viewed as a signal that his challenge from the right is a viable one in this high-profile primary.