Haim Bitton, director of security in this city near the northern tip of Israel, has been preparing for this day for six months. Right after last summer's parliamentary elections, the mayor told him to begin cleaning up the city's 140 public bomb shelters because they would soon be needed again.

Zeev Peleg, the principal of Danziger High School here, waited awhile longer. But by late November, almost two months before the government in Jerusalem made the inevitable decision to begin withdrawing the Army from southern Lebanon, Peleg had reinstituted regular drills in the school so that the children would know how to reach their shelters and what to do when they gathered there.

"I knew it was coming," Peleg said today in his office, about five miles south of the Lebanese border.

What Bitton, Peleg and others here have been preparing for began in earnest yesterday, when the Israeli Army carried out the first stage of its planned three-stage withdrawal from Lebanon. The first stage posed no immediate threat to Qiryat Shemona, but when the withdrawal is completed this community of 14,000 persons again will be in range of Katyusha rockets, the Soviet-made weapons that, in the hands of Palestinian guerrillas in southern Lebanon, constantly threatened and intermittently pounded this and other northern Israeli towns.

That day may come sooner than expected. Israeli radio reported today that government officials, pleased by the smooth initial pullback, may accelerate the withdrawal plan, now scheduled to be completed by summer or early fall. The report said the second stage, in which Israeli troops are to evacuate their positions in eastern Lebanon, could begin in a few weeks.

Menachem Begin, the former prime minister who launched the 1982 invasion, promised that such a day as is now feared here would never come again.

Qiryat Shemona, in 1974, was the site of a bloody terrorist raid by a Lebanon-based Arab force that left 18 residents, most of them women and children, dead, as well as the three Arab attackers. The repeated rocket attacks in 1981 had put the city once again under siege.

In his ringing defense of the Israeli invasion, Begin turned Qiryat Shemona into a slogan, a rationale for all the death and destruction that descended on southern Lebanon with the invasion.

"Katyushas will never again fall on Qiryat Shemona. Never. Never again," he shouted at rallies in support of the war.

But that was nearly three years ago, before more than 600 Israeli soldiers had died in Lebanon, before the war deeply divided Israel and helped to cripple its national economy. Now there is a new government in Jerusalem with a defense minister who speaks in bluntly different terms.

"We never promised that a single Katyusha would not fall anywhere," Yitzhak Rabin said three days after the Cabinet approved the withdrawal plan, "nor will we make such a promise."

Here at the Katyusha front line, where this morning empty Israeli Army trucks rolled north through town on their way to pick up the last of the heavy equipment removed from the Sidon area yesterday, Rabin's message has sunk in and been accepted, perhaps grimly but with the realization that there is no longer a reasonable alternative.

"I feel very good about it," said Maya Ben Adiva, the receptionist at the North Hotel, which has been hit more than once by rockets. "We prefer this the withdrawal . It's better than 600 soldiers killed."

"It's not so much fear that people feel as uncertainty," said Peleg. "They know they won't suffer like they did in 1981. It won't go back to that."

The first half of 1981 was the worst of times for Qiryat Shemona. The population then was 18,000, but amid the pounding of artillery and rocket barrages from the nearby Palestinian bases, more than half of the people fled south. The high school was frequently empty, the children kept at home by their distraught parents. People spent days at a time in the bomb shelters.

Then, in July of that year, a U.S.-sponsored cease-fire took hold and brought 11 months of quiet to Israel's Upper Galilee region. The invasion the next year was meant to eliminate forever the threat that hung over this and other communities in northern Israel. Now, it appears, it may only have bought some time.

Sitting in Peleg's office this morning, Nelly Zafrani, 17, and Shukey Jacobs, 15, said they and their friends were worried about what the coming months will bring as the Army continues its pullback. They are old enough to remember 1981 and are among the children of this region who easily can distinguish between the sounds of incoming and outgoing rocket and artillery fire -- "Ours and theirs," Zafrani said.

It started after midnight one night that year, she said. A friend of hers was killed, and her house was hit in one of the barrages. Jacobs, who lives in Metulla, a small town on the Lebanese border, said he worried less about rockets -- they usually flew overhead on their way to Qiryat Shemona and other targets to the south -- than he did about infiltrators reaching his home at night.

"It was quite frightening," he said. But both students said they and their friends supported the withdrawal decision. They know, as others here do, Zafrani said, that "we have to get out of Lebanon; we can't go on like this."

The government of Prime Minister Shimon Peres invested much time and energy in persuading this town, the symbol of justification for the war, that there is now no alternative to withdrawal. In the days following the Cabinet's decision, Peres, Rabin, Army Chief of Staff Moshe Levy and the Army's northern commander, Maj. Gen. Ori Orr, all visited here to reassure the residents. Their message appears to have been accepted. When Mayor Prosper Azaran, a member of Israel's right-wing Likud bloc, organized a demonstration to protest the withdrawal decision, only about 50 persons showed up.

Bitton, the security chief, said more than half of the public bomb shelters, which suffered widespread vandalism by youths following the invasion, have been restored to usable condition. Another 60 shelters in schools and other areas where children gather, are also ready, their walls freshly painted, their self-contained electrical and air ventilation systems repaired. In some of the shelters, there are rows of metal bunk beds in case of a long siege. A team of local psychologists is about to begin preparing the population, especially the children, for what may lie ahead.

Bitton estimated that the town has spent about $3 million getting ready for a possible renewed onslaught of rockets. It has asked the national government for $1 million in additional aid, and the Army has promised to build 25 new shelters for the town, he said.

The security director said he did not blame Begin for failing to deliver his promise about Qiryat Shemona.

"We were on holiday for 2 1/2 years," he said. "We have finished the holiday, and now we must prepare. Begin promised, and he tried. We're glad he gave us 2 1/2 years of holiday." Map, Israel. By Dave Cook -- The Washington Post