Dan Hirshhorn at Pa2010 reports the Onorato camp is set to start its TV advertising tonight:

With the clock ticking down to primary day, Democratic gubernatorial front-runner Dan Onorato appears to be the first statewide candidate in Pennsylvania with campaign ads on television.

Onorato’s campaign bought its first TV airtime for Tuesday, according to a person close to the campaign. Though the source didn’t indicate the precise size of the purchase, it was described as a “heavy” ad buy, expected to include prime-time lead-in shows Tuesday evening. Reporters from pa2010.com have yet to personally see any campaign ads, but will be on the lookout throughout the day Tuesday.