This fall, the effect of the closing of Northwood High School will be felt keenly in three other high schools in Montgomery County:

At Albert Einstein in Kensington, 151 former Northwood students -- along with other new students in the area -- will boost projected enrollments to 1,793 students, or 95.5 percent of the school's capacity, according to school officials. This year's enrollment was 1,273.

Einstein will add eight portable classrooms, create a third lunch shift, shuffle teachers among classrooms, restrict parking and expand class sizes to the maximums of 28 students for English classes and 32 students for all other classes as recommended by the county school board, Assistant Principal Stuart Marder said.

At John F. Kennedy in Silver Spring, enrollments are expected to rise this fall to 1,649 students, 101 percent of capacity. The school, which had an enrollment this year of 1,578 students, is expected to absorb 145 Northwood transfers, according to registration figures.

Kennedy will add three portable classrooms to the six it has now, said Principal Robert H. Hacker. School officials also plan to install better hallway lights, repair more than 100 broken lockers and spruce up the school building.

At Montgomery Blair in Silver Spring, last year's enrollment of 1,273 students will soar this fall to 2,122 students. The major factors in the increase will be 142 Northwood transfers and 687 new ninth graders. The school did not have a ninth grade this year.

Even with the enrollment jump, however, Blair will reach only 90.5 percent of capacity. As such, it will be the only school that comes close to the board's recommended utilization level of 70 to 90 percent. Blair will need no portable classrooms.

Those who argued earlier this year against closing 29-year-old Northwood said that increased enrollments at the other schools would bring about a decline in the quality of education.

Einstein PTA President William Wisner is quick to disagree. "It's going to be crowded, but students will be better off in terms of the programs that will be available," he said.

Not all students look forward to the change, however. "It's definitely going to be overcrowded," said Demitry Dorfman, an Einstein junior. "Northwood hates Einstein, so there will be a lot of fights."

A 42-member committee of administrators, parents, teachers and students from the four high schools has been working on a consolidation plan since the school board's vote in March to close Northwood. Northwood was originally scheduled to close at the end of the 1983-84 academic year, but the board voted in 1983 to postpone the action.

The administration made reassignment of Northwood's 72 teachers and administrators a top priority, and as of last week, 51 Northwood professional staff members had definite assignments; four had pending assignments; nine were taking leave, resigning or retiring, and eight were waiting for new jobs, said William J. Barrett, a school staffing specialist.

Teachers caught in the turmoil of a school closing can suffer emotional stress that might not show up until as much as six months after changing jobs, said Miriam Cameron, director of the school's professional counseling program.

"There is a tremendous sense of loss of identity," Cameron said. "In the case of Northwood, they were sort of saved at the bell, and then there was a change. I would expect that people from Northwood will need assistance . . . . "

About the only thing the consolidation committee has not worked out, according to committee chairman William F. Brennen, is a contingency plan in the event that the state Board of Education orders Northwood reopened. That is unlikely to happen, though a determined band of Northwood supporters has an appeal pending.

Community activists began battling to save Northwood in 1981, after it was targeted for closing along with 27 other schools. With a resolve unmatched by other communities, they wrote letters, packed public hearings and issued reports to counter administration claims that the facility had outlived its usefulness.

Late last year it appeared that rebounding enrollments might save the school. But in January, Superintendent Wilmer S. Cody recommended shutting Northwood permanently to save the estimated $9 million cost of modernizing its deteriorating buildings. The board concurred in a March 4 vote.

Last month, state hearing examiner Elizabeth L. Nilson upheld the county school board's decision and recommended taking no further action on the appeal. The state board has scheduled a hearing for later this month.

Meanwhile, highly charged opposition among Northwood students has given way to more sober thoughts about picking the right school, the right classes and the right attitude to deal with new -- and in some cases overcrowded -- facilities.

"At first I was planning to go to Kennedy, but . . . I decided to go to Blair because it has a more in-depth honors program," said Nancy Grauzlis. "I wouldn't get busing if I went to Kennedy, so that was a factor, too."

By the time officials finish dismantling it, the aging brick and cinder block building will be reduced to a warehouse for surplus furniture, said Charles F. Francis, Northwood's "closure coordinator."

Francis, who is responsible for giving away books, supplies and teaching materials, said everything has been promised to other schools. All of the school's trophies were offered to the coaches or students who won them, he said.

Athletic jerseys carrying the Northwood Indians logo were sold to varsity and junior varsity players for a dollar each. The feathered headdress worn by the school's mascot is destined for permanent display in the Wheaton library.

Francis even tracked down the parents of a student who died in 1964 to give them the bronze plaque from a small memorial erected by classmates in a Northwood courtyard.