"War in 48 hours," predicted a former senior State Department official.

"I was going to say war in 47 hours," chided NBC-TV's State Department correspondent Bernard Kalb, who gave every indication that he and the ex-official had played games like that before.

"I said to Cap Weinberger, 'Are they going to invade?' " said Hearst correspondent John Wallach. "He said there are only three days of good weather in the whole season down there and one of them is tomorrow."

Everybody laughed. It was a funny line even if the mood at the Moroccan Embassy last night wasn't particularly funny. The occasion was a buffet dinner for about 300 marking the working visit to the United States by King Hassan II.

He arrived a half-hour or so after the guests and created the usual flurry that accompanies royalty. Inside the huge yellow and white tent that had been erected on the side of the embassy residence, exotic incense perfumed the air. Hassan briefly greeted guests but soon disappeared, leaving them to devour the opulent display of traditional Moroccan couscous, chicken and olives and pigeon pie.

"I've gotten every known estimate," Kalb continued. "We're surrounded by an awful lot of guys in pin stripes who think they're generals. I've heard 24 hours, I've heard 48 hours. I have some guys attacking late in October. I have people waiting for Christmas."

Everybody seemed to have an opinion about when--not if--Great Britain would invade the Falklands. Probably even the king had an opinion. He and Secretary of State Alexander M. Haig Jr. met for nearly an hour behind closed doors during the party along with their ambassadors, Ali Bengelloun and Joseph Reed.

"A global, regional and specific review," said Reed later. That meant the Iran-Iraq conflict as well as the crisis between Argentina and Great Britain.

"I don't want to get into it here," said Organization of American States Secretary General Alejandro Orfila who, like everyone else, was waiting to hear whether the United Nations Security Council had made any progress in last-minute proposals to find a peaceful solution. "The Argentines feel I say too little, the others feel I say too much."

The fatalism about the potential for all-out war overshadowed the purpose of King Hassan's visit, which was to negotiate weapon sales and the use of a Moroccan air base by the United States.

"It's a facility, not a base," said Defense Secretary Caspar Weinberger, one of several top-level administration officials at the party. "I would be very hopeful that we would be able to reach an agreement on it."

On the issue of the equipment, Weinberger said that "we have a modest amount for foreign military sales in the budget but Congress hasn't acted on it yet. Everybody I know of agrees that Morocco needs some help."

Before he disappeared into his meeting with the king, Haig spoke of "very successful meetings so far, but we've got more work to do."

Secretary of Commerce Malcolm Baldrige, who had been among those lunching with President Reagan and the king, said the two had gotten along "famously on everything from international relations to old cavalry stories."

The crowd was deep with high- and low-ranking government officials, former officials and selected socialites, many with stories to tell about "the king and I."

Foreign affairs analyst Joseph Sisco, once Henry Kissinger's shuttle companion, told one about dropping into Morocco to brief Hassan.

"We walked into his conference room, sat down and the left rear leg of my chair crumbled and I fell flat on the floor," said Sisco. "Two weeks later we returned to do another briefing and the king said to me, 'Look, Joe, new table, new chairs.' Tonight I said to him, 'Your majesty, have you broken any furniture lately?' He smiled."