With the upfront TV ad market about to start, it's beginning to look a lot gloomier.

Media buyers and forecasters are reluctant to guess how much money advertisers will spend. But one thing is certain: It isn’t going to be good for the broadcast networks.

Cable television will benefit from broadcasters’ slumping ratings but will probably see only a slight increase.

Now the overall upfront is expected to be flat to down from last year's $24.5 billion across broadcast, cable and syndicated television.

Just a few months ago, the outlook was a lot rosier, with the broadcast networks expected to see some gains and the cable networks seeing major gains.

What's changed?

For one, broadcast ratings have plummeted, leaving the networks with far less inventory to sell.

But more worrisome, advertiser demand has weakened with an economy that seems to worsen by the week, according to media buyers.

“I think demand will be down, partially due to whatever recession we may or may not be in,” says Larry Novenstern, executive vice president and joint managing director of newcast at Optimedia.

“The automotive marketplace is really bad, and other advertisers will be cutting back spending and moving more to cable. Everyone thinks overall spending will be down a bit.”

At best, Merrill Lynch analyst Jessica Reif Cohen expects spending to be up 1 percent, to just under $25 billion. But she thinks it could also sink, falling by as much as 8 percent if it turns into a bear market for ad sellers.

One key indicator for media buyers has been weakening demand in the scatter market, when inventory not sold in the prior upfront is auctioned off. A strong scatter market is typically read as an indicator of a strong upfront, a weak scatter market indicating a weak one.

The scatter market had been robust for months, but that was in large part because the supply of rating points was down, which meant that buyers were forced to book more spots to achieve prior years’ reach and frequency goals. It was less a case of strong advertiser demand.

Now, the supply of rating points is down but so is advertising demand. And with ratings down so much the broadcast networks will have an even tougher time getting higher prices over last year.

Network TV’s primetime rating in 18-49s tumbled 9 percent from the year-earlier period in the just-concluded broadcast season, according to a Magna Global analysis of Nielsen ratings. Only Fox posted an increase. Ad-supported cable was up 9 percent.

Most troublesome for broadcast is that ratings didn’t bounce back once the networks had original episodes back on the air around April following the end of the writers' strike in February.

"Viewers disenchanted with the writers’ strike abandoned broadcast TV and tuned to cable or found other options to fill their time," says Michele Toller, director of national broadcast at Empower MediaMarketing.

The broadcast networks’ 18-49 rating prior to the strike was a 15.4, according to the Cabletelevision Advertising Bureau. It dipped to 13.9 during the strike and to a 13 rating in the period after the strike ended.

Further, there's no reason to bet they will bounce back in the fall, argues Brad Adgate, senior vice president and corporate research director at Horizon Media.

“You can’t give the networks the benefit of the doubt because ratings didn’t come back after the strike,” he says. “I don’t think there will be a spike because there never has been. Why would that start now?”

Further adding to the uncertainty of this upfront is the absence of any sense of urgency that's been typical of past upfronts. That’s partly due to the expected shift in ad dollars to cable TV.

With broadcast, prime inventory is limited, so media buyers traditionally felt a need to rush in and lock it down. Cable has a relatively large supply of inventory, meaning buyers can pick over inventory until they get the rating points they need at the prices they want.

Most buyers say negotiations haven’t begun in earnest and probably won’t for another week or more.

“I don’t think it’s going to be a fast market,” says Toller. “Advertisers and agencies are going to be very methodical and take their time to evaluate and make the best selections for their clients.”