DENVER — Former Senate aide Betsy Markey (D), challenging Rep. Marilyn Musgrave (R) in Colorado’s 4th district, is scheduled to hit the airwaves with her first television ad.

The 30-second biography spot will debut on Tuesday with a 1,000-gross ratings points buy on cable television in Weld County, part of the district’s northern region that is considered a key to Markey’s hopes of ousting Musgrave in a majority Republican area.

The ad was produced by Washington, D.C.-based Envision Communications.