As the third day of the gulf war began Friday morning, the broadcast networks ended their round-the-clock coverage - pending further developments.

ABC, CBS and NBC all resumed regular programming Friday at 10 a.m. MST. But each has promised to cut into entertainment shows with news if events in the Persian Gulf warrant it."It's kind of hard to call," said a spokeswoman for NBC. "We're planning to go with regular programming, but you never know when something will happen.

"About the only thing you can do is tune in and see."

As a matter of fact, only about 90 minutes after the networks resumed their normal lineup of soap operas and game shows Friday morning, they were once again pre-empted. Air raid sirens sounded in Israel, and the news people were back on the air.

About 45 minutes later, it was back to the soaps.

"All of our programming is subject to developments in the Middle East," said Terry Soreco of CBS. "I could tell you what we've got planned for tonight, and as soon as I hang up the phone that all changes.

"For example, we were supposed to air `Knots Landing' (Thursday) night. Then they bombed Israel and `Knots Landing' was off the air.

"We sit here and look at the news and we say, `OK, those plans are all down the drain. Let's make new plans.' I've seen at least five different schedules for (Friday) night's lineup."

All the broadcast networks are planning to carry regular sports programming this weekend, including the NHL All-Star Game on Saturday morning and Sunday's NFL playoff games. But NBC and CBS are quick to hedge that a bit by stating that even the NFL may have to make way for the news.

The Fox lineup, seen locally on KSTU-Ch. 13, is unaffected by the crisis. So are most cable channels, although some like WGN have picked up CNN's coverage.

Locally, KXIV-Ch. 14 is no longer scheduling CNN for its programming but, like the networks, will hook back into the cable channel pending further developments.