As reported by the AP via ABC News:
The Democratic Congressional Campaign Committee on Thursday began reserving advertising time with television stations across the country. Where and when the House Democrats' campaign arm is looking to spend money…
—$1.4 million on Denver broadcast and cable ads from Oct. 21 to Nov. 4 to challenge Rep. Mike Coffman, a Republican.
Different media markets have different cost factors, but in absolute terms, only a few races are seeing more investment from the Democratic Congressional Campaign Committee (DCCC)–races in pricey markets like New York and Philadephia, and a particularly tight freshman protect effort in Phoenix. Once you account for the difference in ad rates for these markets, clearly no practical expense is being spared in the drive to unseat Rep. Mike Coffman. Spending by the DCCC and like entities on the other side is a reliable indicator of where strategists believe their best chances lie.
It's just another confirmation of what our readers already know–CD-6 is the marquee congressional race in Colorado this year.