The Arlington School Board tomorrow night begins the first of what promises to be dozens of public meetings this year on proposed school closings.

The meeting at 7:30 p.m. at the Education Center is strictly an informational session, focusing on a report from Superintendent Charles E. Nunley outlining several consolidation options and grade realignments to deal with declining enrollments in elementary and secondary schools in Arlington.

The bulk of Nunley's report, gleaned from a similar report prepared by the Jefferson County, Kentucky, Schools (Louisville) in 1978, deals with possible grade realignments for kindergarten through grade 12. Nunley's report, requested by the school board in June, is for discussion and is designed to augment school closing reports prepared by citizens' panels last spring.

No decisions on school closings are expected until April, following extensive public hearings, and no schools are expected to be closed until the fall of 1984. Nunley tentatively is scheduled to present a reorganization plan in October or November.

Nunley said he will make no specific recommendations in his report this week, but will focus on providing the board with information about the most common grade groupings in school districts across the country and "the advantages and disadvantages of each."

Currently, Arlington has three grade groupings: kindergarten through six (elementary schools), grades seven and eight (intermediate schools) and grades nine through 12 (high schools). The major problem with the current system, Nunley's report says, is there are usually too few pupils at the intermediate level to operate those schools economically. The report says a major advantage is that intermediate students, because of the smaller school size, generally receive more individual attention.

Nunley's report lists seven options to the current system. The most common grouping, the report says, is grades 1-5, 6-8 and 9-12. That system, the report says, would have particular advantages for the intermediate level. For instance, the report says, grades 6-8 are more homogeneous than 1-6, and the grouping would allow students to start specialized classes, similar to high school schedules, earlier. The grouping also would allow the system to retain high schools as they are now set up.

One problem is that many teachers might have to seek recertification in specific subjects to teach in a grade 6-8 intermediate school. Although elementary teachers in Virginia are certified to teach kindergarten through seventh grade, they general are certified to teach specific subjects such as a foreign language.

In his report, Nunley projects an enrollment decline of 4 percent a year until 1984, leaving the school system with 5,922 elementary pupils and 5,920 secondary students. This fall, school officials estimate they will have 7,143 elementary students and 7,174 secondary students.

Using the enrollment projections, Nunley has estimated the number of buildings needed to accommodate students under each of the seven group options.

The report assumes the county's three alternative schools -- Drew Elementary, Page Traditional and H-B Woodlawn Secondary School -- would be continued, but could be relocated near or within other schools.

Nunley also was asked to assess the impact of splitting the county high schools into 9 and 10 and 11 and 12.

A panel of high school principals, appointed by Nunley, consulted officials in Alexandria, which once had such a system. The Arlington panel reported that the arrangement was feasible, but that careful planning was required. Special consideration must be given to curriculum development, extracurricular activities, counseling, class sizes, teacher morale and assignments, racial balance and transportation, among other factors, the Arlington principals said.