The NRCC believes both longtime centrist congressmen are vulnerable heading into 2014.

McIntyre held on by the skin of his teeth in the 2012 election and is facing a rematch against the same candidate in a heavily Republican district. Peterson has been targeted early on in other years, however, and so far has easily defeated his opponents in the GOP-leaning district.

The ads will run on cable next week. The NRCC has spent $10,000 on cable time in the Wilmington, N.C., market against McIntyre and a combined $22,000 in Minneapolis and Fargo, N.D., to target Peterson, according to the source.

"With ad buys this small, the only people who will see it is the college student on summer vacation who watches TV all day long," the Democratic operative says.

Early ad buys from the party committees often indicate where the committees see opportunities to sway voters.