COLUMBIA, S.C., SEPT. 11 -- Pope John Paul II preached reconciliation to Jews and non-Catholic Christians today, and while those pleas were well received, the second day of his American journey brought little but disappointment to 250,000 of his flock -- Miamians whose papal Mass celebration was cut short by a violent lightning storm.

His long day of meetings and travel through the American south began in Miami, where, at a meeting with 160 Jewish leaders, he called for strong church efforts to combat anti-Semitism, promised to support a study of Pope Pius XII's role in resisting Nazis during World War II and affirmed Israel's right to exist as a Jewish nation.

He was met with silence when he said that Palestinians also deserve a country of their own. But Jewish leaders said the session, with one last week at the Vatican, held the promise of a "new beginning" for Jewish-Catholic relations in this country. "I think he made a very moving statement," said Rabbi Mordecai Waxman, honorary president of the Synagogue Council of America.

From there the pope traveled to Tamiami Park, where a quarter-million Floridians, many of whom had camped there overnight, greeted him for a Mass that began with great enthusiasm and ended in disarray.

Just as the pope began celebrating Mass, as he uttered "Let us pray," a deafening thunderclap shook the air and lightning streaked from the sky to a sound tower on the Mass site. It soon started to rain. When the lightning continued, the Secret Service, in charge of the pope's safety during his 10-day trip, canceled the rest of the celebration.

"There's a slight chance of lightning," an announcer had said, warning worshipers away from the towers before the Mass, "and we wouldn't want to send any of you home to God today." Everyone laughed and traded jokes about divine symbolism, but later they were sent home.

From the rain of Miami, the pope traveled to the heat of Columbia, S.C., where he preached Christian unity in this center of Bible-Belt Protestantism. He sternly warned Americans against letting their love of freedom lead them morally astray.

"It would be a great tragedy for the entire human family if the United States, which prides itself on its consecration to freedom, were to lose sight of the true meaning of that noble word," the pope said in a homily during an ecumenical service at the University of South Carolina Gamecocks' stadium.

"America: you cannot insist on the right to choose, without insisting on the duty to choose well, the duty to choose the truth. Already there is much breakdown and pain in your own society because fundamental values, essential to the well-being of individuals, families and the entire nation, are being emptied of their real content," the pope told about 50,000 worshipers in the stadium on the outskirts of the South Carolina capital.

"Surely by now we must be convinced that only by recognizing the primacy of moral values can we use the immense possibilities offered by science and material progress to bring about the advancement of the human person in truth, freedom and dignity," he concluded.

The pope also met here with representatives of 27 non-Catholic Christian churches nationwide to continue the ecumenical dialogue pursued by the Roman Catholic church since the Second Vatican Council called in 1964 for Christian unity.

Vatican officials said the pope chose sweltering Columbia for such a gathering from around the United States because South Carolina is the state with the smallest percentage of Catholics. Catholics constitute 2.1 percent of the state's 3.35 million residents.

Baptists are by far the state's dominant denomination with about 1.3 million adherents, and Methodists are the second-largest religious group. Both were well represented among the clerics who met the pope at the residence of James B. Holderman, president of the University of South Carolina. Other leading protestant denominations represented at the meeting were Lutherans, Presbyterians and the Disciples of Christ. Other major U.S. churches represented were the Greek Orthodox, the Orthodox Church of the United States, and the Armenian Apostolic Church of America.

"We greatly appreciate that you have made this visit to our country," said Bishop Philip R. Cousin, secretary of the Council of Bishops of the African Methodist Episcopal Church on behalf of the non-Catholic clerics, "for we believe it is important that you become better acquainted with Christianity in America and with our nation, and that we as Christians and citizens here increase our understanding of you and your ministry."

The 67-year-old Polish pope responded that while many areas of disagreement remain among churches, "it is no small achievement of the ecumenical movement that after centuries of mistrust, we humbly and sincerely recognize in each other's communities the presence and fruitfulness of Christ's gifts at work."

"I have the feeling of coming from a historic event," said the Rev. William Rush, ecumenical officer for the Lutheran Church in America at the end of the meeting. "It is hard to imagine even a few years ago an event like this taking place."

Meanwhile, former president Jimmy Carter and his wife, Rosalynn, met with the pope for five minutes at Columbia's airport before the pontiff flew off to New Orleans. At one point, Carter had canceled the meeting so he could be with his brother, Billy, 50, who was diagnosed yesterday as having inoperable pancreatic cancer.

The pope, adhering to a tight schedule that put him in three cities in a single day, arrived tonight in New Orleans, where he will meet Saturday with black Catholics and Catholic educators. He will spend Sunday in San Antonio and Monday in Phoenix before going on to Los Angeles; Monterey, Calif., San Francisco, and Detroit.

For Miami, the canceled Mass was a bittersweet ending to a visit that was 18 months in the planning and that, at least temporarily, had brought a sense of pride and unity to a city troubled by drug-related crime and a widening police-corruption scandal.

The Mass, believed to be the first to be canceled since the pope began traveling in 1979, was supposed to be the jubilant culmination not only of the pope's 24 hours in Miami but of exhaustive planning by local Catholic and government officials and thousands of volunteers. In the end, as the pope was forced to conclude the liturgy in the privacy of a trailer behind the altar, a quarter-million Floridians slogged home, disconsolate, in the rain.

The temperature had been 85 degrees by 9 a.m. when the storm clouds gathered over the park, at first providing welcome relief during the wait for the pope. The heat and humidity had been oppressive since dawn, and 119 people already had been treated for heatstroke.

When a light rain began to fall, then stopped as the pope's bubble-topped, bullet-proof vehicle made its way through the crowd close to 10 a.m., the weather looked like nothing to rival the Cameroon downpour or the New Zealand wind storm in which Pope John Paul II has preached. But the lightning did him in.

"Let us pray," the pope said.

Crack!

The pope jerked his head, and tens of thousands of people jumped and screamed as a deafening thunderclap sounded and lightning struck Sound Tower 6. Soon he pressed on, and he had barely begun his homily -- referring to Florida as "this beautiful land of the sun" -- when the storm forced him away from the microphone.

" 'Of the sun' often also means of the rain," he ad-libbed when he resumed. But he stopped again and smiled silently on the people as they danced in the rain, chanting " Viva El Papa!" and refusing to acknowledge what was, finally, the end.

The pope's undelivered homily had a special message for Miami's large immigrant community and also a broader lesson on the Vatican definition of morality for all America.

His audience, full of transplanted Cubans, Nicaraguans and Haitians who have made Miami a cultural crossroads, would have heard him say: "I take this occasion to assure you of the church's particular concern for those who leave their native countries in suffering and desperation. The frequent repetition of this experience is one of the saddest phenomena of our century."

His statement on morality, also undelivered, was reminiscent of one he had made during his final homily in Washington, D.C., during his first American journey in 1979. The text for his Miami homily put it this way: "Family life is subjected to powerful pressures as fornication, adultery, divorce and contraception are wrongly regarded as acceptable by many. The unborn are cruelly killed and the lives of the elderly are in serious danger from a mentality that would open the door wide to euthanasia."

That is what the pope intended to say, but he was prevented by what is often, in other circumstances, called an act of God.