The heavens thundered, the sky opened up, rain pounded the pavement of Manhattan. A Kennedy supporter at a New York magazine party last night looked up and said: "God just found out about the vote."

Inside this party at the American Charcuteri on West 52nd Street, talk of Kennedy the dropout wafted from Perrier to Scotch and back. "This way," said Mayor Edward Koch, "instead of having a bloodletting, with viens and arteries, all we did was cut a little capillary."

And from columnist Pete Hamill: "It's all over. Everything else is footnotes."

This particular party pulled in a collection of literary and media sorts: Atlantic Monthly editor Robert Manning, literary agent Sterling Lord, "60 Minutes" correspondent Morely Safer, Norman and Frances Lear, Village Voice writer Nat Hentoff, a motley crew of writers and reporters, but also a party critic. He came in the form of Jerzy Kosinski, who wrote "Being There."

Here's his analysis of the Washington party versus the New York party:

"Washington has a political pyramid. There's a hierarchy of importance and we all know that. New York has no pyramid, but there are a variety of little hills. This party is one of them." Kosinski has been amusing himself during convention week by following delegates around. "The prey among the predators of New York" is how he puts it. Anyway, two nights ago he picked out an interesting group of delegates and watched them on the sly.

"They went to a very expensive restaurant and ate and drank and then afterward, the men discharged the ladies."

So the women went back to their hotels. And what did the men do? "They proved," he said, "that the Democratic Party has a wide spectrum of community standards." Disco and Victory

A short ways uptown, a Carter/Mondale party for black delegates and alternates was rapidly turning into a victory celebration. Disco throbbed on the first floor of the Regine's and soulful music on the second. Between the two, Carter media advisor Jerry Rafshoon was smiling wide.

"Feeling good," he said.

But what about Reagan in the fall?

"Well, it's always been hard," he said. "It's never been easy. Jimmy Carter has always had a hard campaign, and he's always been underestimated. Anyway [he looked around the room here], I'm a little too old for this music." He trotted off.

Deep in the crowd were Rep. Charles Rangel (D-N.Y.), assistant secretary of labor Ernie Green, and Georgia State Sen. Julian Bond. He is a Kennedy supporter. His mood matched the weather.

"I should rather have seen it lost on Wednesday night than like this," he sighed. Jackie at 21

Everybody was calling it "Breakfast with Jackie," but as it turned out, Jackie Kennedy Onassis didn't so much as touch a dainty pecan roll. Ted Kennedy whisked her through a 21 Club breakfast fund-raiser, then whisked her back out, faster than you could count all his kin.

But the glimpse was enough. "Oh, I just love this," said one woman who didn't eat her scrambled eggs. "And I just love what she's wearing."

Which was a brownish silk polka-dot dress that made her look exquistely thin, and radiant, for 9 a.m.

"Well, who is this smiling face this morning?" Jackie said to Eunice Shriver, who didn't look quite as fresh and dewy.

In the 300-plus crowd at $100 a head were Kennedy faithfuls like Ted Sorenson, Arthur Schlesinger and George Stevens. Everybody else was either an organizer, a delegate, or wealthy. Or familey, like Kerry Kennedy, Stephen Smith, and Maria Shriver.

Ted Kennedy spoke briefly, saying to the crowd, "You're all invited to dinner at the White House."

But, said one backer: "I think it's going to take a miracle." Breakfast at Cartier

Barely a block away, Cartier was serving raspberries and champagne among the jewels. It was a breakfast for senators, governors and their wives, but heaviest on wives and daughters who came to gape and fog up the glass cases.

"You can't go wrong here," said one governor's daughter. "Just close your eyes."

Not everyone was as inspired, most particularly a certain 21-year-old son of a certain well-known senator.

"My dad sleazed out of this," said the son, who was standing in the corner. "So my mother took me, and here I am. But I guess raspberries and champagne isn't a bad way to start out." Faux Pas for Lunch

Let's hope the Democratic National Finance Council is a little better with numbers than it is with spelling for basic identification of significant persons.

Yesterday, at a humongous luncheon honoring Cabinet members at the Plaza Hotel, Finance Council Chairman Charles Manatt introduced Ambassador Averell Harriman as "Gov. Armand Hammer." And Dnc Treasurer Peter Kelly, after grandly introducing the Cabinet members to the crowd, was about to slide into some prepared remarks, when Health and Human Services Secretary Patricia Roberts Harris whispered loudly toward the podium, "Landrieu!"

"Oh," said Kelly, "and we could never forget Moon Landrieu!" The HUD secretary took a bow. It was not known whether he noticed his name spelled on the program as "Landriew."

At any rate, he was partaking heartily of a meal that included four flavors of mousse: strawberry, lemon, chocolate and raspberry.

"How do I look?" he said. "Nice and fat? I don't look like I'm wasting away, do I?" Civility at Sardi's

After a Kennedy fund-raiser at the Shubert Theatre Sunday night, a bunch of his supporters headed for Sardi's. They wound up sitting perilously close to Carter adviser Charles Kirbo, who was having dinner with his family.

But no fireworks, said the maitre d'. His report: "Everybody was very civilized." Summer wonderland

The sycamore trees of Gracie Mansion cast but small shade on the sweating congressmen below, and so an outdoor musical trio, feeling wicked, launched into "Button Up Your Overcoat." None of the legislators even noticed.

"They're just not -- should I use the word -- cultured," griped the bass player. And with that, as the congressmen from states beginning with A through M drank wine and carried on, the trio began to play "Let It Snow." Serious Salsa

"If you don't party, you can't conduct business," Edwin Cruz, a member of Hispanic American Democrats, was saying as he cradled his pina colada.

On that theory, there was a great deal of business going on at Victor's Cafe on 52nd Street yesterday. The funny thing was, most anybody else would swear this reception for Hispanic delegates was one deadly serious party.

A salsa band blared Puerto Rican music and waiters served mounds of Cuban food as Hispanics danced into the evening.

In the middle of this scene stood Treasury Secretary G. William Miller.

"Yo hablo espanol muy bien," he said.

Translation: "I speak Spanish very well." But pretty soon, off he went to the rules debate where, presumably he spoke English.