The WGA leadership continues to apply pressure on TV networks and studios ahead of resuming contract negotiations next Monday. WGA West executive director David Young has sent a letter to ad buyers warning them they may be wasting their money if there’s a writers’ strike come May 2, sources confirmed to Deadline.

“With the cable networks’ upfronts underway and the broadcast networks’ upfronts beginning in May, I am writing to inform you of a potential labor dispute that could have a significant impact on primetime programming for the 2017-2018 television season,” Young wrote in the letter.

CBS

While the effect of a possible strike on primetime scripted series for the next broadcast season —  which will be presented at the May upfronts and sold to advertisers shortly thereafter — is unclear as the strike would fall during their scheduled hiatuses, there would be an immediate impact on the networks’ late-night shows in the final weeks of the current season. During the 2007-2008 writers strike, all late-night shows went dark at the beginning of the strike, eventually returning on the air seven weeks into the work stoppage without writers — with the exception of CBS’ Late Show and Late Late Show, whose owner, David Letterman’s company, reached an interim agreement with the WGA.

In the event of a strike, Young wrote in his letter, “late night shows, including Tonight Show Starring Jimmy Fallon, The Daily Show, Jimmy Kimmel Live, Saturday Night Live, Full Frontal With Samantha Bee, The Late Show With Stephen Colbert and others will go off the air,” adding that “some scripted series scheduled to air in the summer of 2017 may be affected as writing and producing for the season is ongoing.”

The producers’ rep AMPTP responded to the letter today, parroting its statement from Monday. “Our objective continues to be to reach an agreement with the WGA at the bargaining table. We hope the Guild will engage with us on the issues in that forum when negotiations resume on Monday.”

The first round of talks started March 13 and broke off March 24, with each side blaming the other for walking away from the bargaining table. Leaders of the WGA West and WGA East are urging their members to give them the authority to call a strike if the second round of talks fails to produce a fair contract.

The main issues are more money for film and TV writers and a bailout of the WGA Health Plan, which faces a projected $145 million in deficits over the next four years.